Atrial Fibrillation – Part 2 – Blood thinners

By Julian Booker, MD

Although we identify only four chambers with a normal human heart, the left atrium has a small finger-like pouch attachment most commonly called the appendage.

Heart left atrial appendage transesophageal echocardiography view (Photo credit: Wikipedia)

Blood flow within the appendage can be slower than the rest of the left atrium. Although many cardiologists would argue, the left atrial appendage does have value. It has been shown to help in the following ways:

1. It acts as a decompression chamber to help the heart deal with unusually elevated pressures within the left atrium
2. It produces atrial natriuretic peptide, which helps the body eliminate excess salt and water.
3. Removal of the appendage has been shown to decrease cardiac output.

Unfortunately, when a patient has atrial fibrillation, there is a major downside. Relatively slow blood flow now becomes stagnant blood. We all know that stagnant blood becomes clotted blood. Blood clots within the heart are dangerous not so much because of any particular harm done to the heart but because the danger that a liberated blood clot poses to the remainder of the body, particularly the brain.

A person with atrial fibrillation is five times more likely to have a stroke than a person without atrial fibrillation. About 15% of stroke patients also have atrial fibrillation. The risk of stroke in the setting of atrial fibrillation is not equal across the board. Certain conditions have been found to increase your risk of stroke in the setting of atrial fibrillation.

1. Increasing age
2. The presence of congestive heart failure or a weak heart
3. High blood pressure
4. Diabetes
5. A prior stroke, transient ischemic attack (sometimes called a TIA or mini stroke) or blood clot
6. A prior history vascular disease, sometimes called hardening of the arteries. Some examples are Peripheral Artery Disease, blockages of your carotid arteries, prior heart attack, atherosclerosis of your aorta.
7. Female gender

If you have one of the above conditions then the risk of blood thinners* should be weighed against the risk of bleeding. If you have none of the above risk factors then no anticoagulation or aspirin may be adequate. If you have only one risk factor then your doctor may give you the option of aspirin or a proper blood thinner. If you have more than one risk factor then blood thinners should be strongly considered. You may only need one risk factor if you older than 75 years or have had a prior stroke or TIA to be strongly considered. For patients with a history of rheumatic mitral stenosis or a prosthetic heart valve, your risk is significantly higher and blood thinners are highly recommended.

Currently there are three blood thinners for higher risk atrial fibrillation. Each has pros and cons that will be discussed here briefly. You will need to have an honest discussion with your health care provider to decide which is right for you.

Warfarin (Coumadin) –

Warning label on a tube of rat poison laid on a dike of the Scheldt river in Steendorp, Belgium. The tube contains bromadiolone, a second-generation (“super-warfarin”) anticoagulant. (Photo credit: Wikipedia)

This medication is Old Faithful.  It started its illustrious career as a lowly rat poison but has reached heights that it never imagined. It is the blood thinner that patients are most curious about. Dosing is once daily, it has been available forever and we understand how to use it. Five decades of use have proven that this vitamin K antagonist reduces the risk of stroke in patients with atrial fibrillation. Unfortunately, warfarin is very finicky and can be difficult to find the correct dose for you. The target range of effect is very narrow which further makes dosing difficult. If you blood is too thick, you are not fully protected from stroke. If your blood is too thin, your risk of bleeding is higher. You will need frequent checks of your INR (a blood test to follow the blood’s thickness) to make sure that you are within range.

When dosed properly, warfarin can be a powerful ally but in the case of warfarin life can get in the way. There is a list of medications as long as my arm that has a direct effect on warfarin’s potency. Most result in increasing its potency and potentially place you in danger from bleeding.  Many foods we eat, especially green leafy vegetables, decrease its effectiveness and place you at risk of developing clots. If you are going to be on warfarin, you must meticulously keep track of what you put in your body.

There are some really good things about warfarin that may make it appealing to you. Because it is a really old drug, it can be very inexpensive. If the costs of lab work are excluded it can be as low as pennies per day. The other really good thing about warfarin is that it is reversible.  The “antidote” is vitamin K, a substance commonly found in green leafy foods. Should you have an issue with bleeding while on warfarin, we can correct you blood levels without issuing plasma.

Dabigatran (Pradaxa)

1127 Pradaxa (dabigatran) cápsula abierta con gránulos (Photo credit: ec-jpr)

– This is an oral direct thrombin inhibitor that is not approved for atrial fibrillation associated with valvular heart disease. It was the first medication not named warfarin that the FDA gave the seal of approval for the anticoagulation of atrial fibrillation. Although dosing is twice daily, many patients find it more convenient than warfarin because there is no need to constantly follow-up with your health care provider for the pesky INR checks. There is also far fewer interaction with medications and food.

Rivaroxaban (Xarelto) and Apixaban (Eliquis) – These medications fall under the category of factor Xa inhibitors. They work at a different place in the clotting cascade than do Pradaxa but for your purposes, you can consider the thrombin inhibitors and Xa inhibitors as one in the same. Dosing is once daily in the case of Xarelto and twice daily for Eliquis.

As you might imagine, there are some downsides to direct thrombin and Xa inhibitors. Compared to warfarin, the medication can be quite expensive. For Pradaxa and Eliquis, dosing must be adjusted if you have kidney dysfunction. Failure to make the proper adjustments could result in too large a dose and bleeding complications. If you have severe kidney dysfunction, all three should probably be avoided. When bleeding does occur, it is not as easy to fix as with warfarin. The intervention for bleeding may be as simple as discontinuing the drug in most cases but can be as significant as short-term dialysis for rare cases.

I see all the law firm commercials on television about the risks of blood thinners. They are enough to frighten anyone. The decision to start anticoagulation because of a diagnosis of atrial fibrillation can be a difficult one. Talk with your doctor; it could save your life.

*These medicines do not actually thin your blood. They alter your clotting potential. Your blood viscosity of your blood remains the same 😉

Related articles

• Atrial Fibrillation – Part 1 – What is it? (myheartnet.wordpress.com)

Atrial Fibrillation – Part 1 – What is it?

By Julian Booker, MD

Atrial fibrillation, sometimes called a-fib, is the commonest cardiac arrhythmia (abnormal heart rhythm). In contrast to the metronome-like heart rhythm that we are used to, atrial fibrillation is characterized by an irregularly irregular heartbeat. If you were to check your pulse, there would be no pattern. The timing of your heartbeat would almost seem random. The heart rate is usually fast but may be slow. You may experience palpitations or you may be asymptomatic.

What is happening in atrial fibrillation?

Before we go into depth about atrial fibrillation, we should probably discuss normal sinus rhythm which is the heart’s normal rhythm. The normal heart beat requires an amazing coordination between several moving parts. The heart can be thought of as two sets of chambers:

1. Ventricles – these are the engines that make your body go. They are incredibly muscular and powerful. The right ventricle pumps blood to the lungs to your blood cells can pick up the oxygen that your body needs. The left ventricle delivers that oxygen rich blood to the remainder of the body.
2. Atria – these chambers that sit atop the heart and serve as reservoirs for blood. Blood collects in the atria and remains there until the ventricles are ready to receive it. The right atrium provides blood to the right ventricle and as you might imagine, the left atrium does the same for the left ventricle.

Your heart has its own pacemaker and specialized electrical wiring that coordinates atrial and ventricular contraction to maximize your hearts effectiveness. The pacemaker for your heart is present in your right atrium so the rhythm of your hearts perpetual dance is choreographed by the atrium.

In atrial fibrillation, there is a short circuit in the electrical system of the atria. Truthfully, short circuit may be too benign a description. During atrial fibrillation, the tissue of the atria is experiencing an electrical storm or seizure.

Atrial fibrillation (Photo credit: Wikipedia)

This results in a complete discoordinaton of atrial contraction. Instead of generating a good hearty (no pun intended) squeeze, the muscle just rapidly twitches. Because the atria set the pace for the heartbeat, an irregular atrial rhythm means an irregular ventricular rhythm.

The lack of squeeze by the atria has two major effects. The ventricles rely on the atria to help them fill to capacity. Without effective filling, there is potentially less blood flow delivered to the body with each heartbeat. This may result in fatigue, shortness of breath, weakness, leg swelling and a host of other symptoms relating to changes in the volume of circulated blood. The second is that blood has a tendency to stagnate within the atrium. Slow moving blood tends to clot and you don’t have to be a heart doctor to realize that blood clots within your heart are probably bad. These blood clots love visiting your brain and are a leading cause of stroke.

How is it diagnosed?

Atrial fibrillation is diagnosed by electrocardiogram (ECG or EKG). There is a characteristic lack of p-waves seen on the ECG. The p-wave is seen during coordinated electrical activity of the atrium. Since we know that atrial fibrillation is a rapid uncoordinated twitching of atrial muscle, the ECG shows something very similar. The most telling consequence is that the QRS, the ECGs representation of the ventricle doing its job, is also irregular.

Who gets atrial fibrillation?

Atrial fibrillation is more common in men than in women. It becomes more common with increasing age. If you have a strong family history of atrial fibrillation you may be at increased risk to develop the condition. A number of cardiopulmonary conditions such as COPD, hypertension, coronary artery disease, mitral valve disease and heart failure also increase your risk. Other seemingly unrelated conditions like heavy alcohol usage and hyperthyroidism have also been shown to cause atrial fibrillation.

In subsequent posts, I will go into more detail on the evaluation and treatment options so check back soon.

The 35-45 Year Old Health Check – (Part 2)- The History

By Murtaza Ahmed MD

Many people have come to think that the bulk of a health check consists of blood tests.  While blood tests are very important and have their role, they are by no means the be all and end all when it comes to deciding if you are healthy.  There are some Physicians out there who have become lazy and simply churn out forms for blood tests without first assessing the patient.  As well as being irresponsible, this can be potentially dangerous as people can go away thinking they have the all clear when really many issues weren’t even addressed.

A common term we use that dates back to the beginning of medicine is ‘the history’.  This is the most important part of any medical consultation and one should always begin with it.  It means taking a story via open and closed questions in order to gather all the necessary information we require.  History taking is a skill, and a well qualified Physician should be able to guide you into giving all the necessary information.  So what should you expect to be asked in a health check and why?

How are things going and do you have any particular concerns?

This will enable you to give a brief picture into how things are for you at the moment as well as allowing you to raise any particular concerns you have that you would like addressed.  This is important as it will guide your Physician as to the general path of the consult as well as make sure there will be time to address particular concerns you have.

Do you suffer from any previous medical issues and are you on any medications?

Also known as the ‘past medical’ and ‘past drug’ history, this information is vital in allowing you to be properly investigated and assessed.  If someone doesn’t ask you this they may be missing crucial information that will result in substandard care.  If you have a regular Physician they may not ask you as they are already aware but if you are visiting someone new then make sure you inform them of all your past medical issues.

Are there any diseases that are prevalent in your family?    

Also known as the ‘family history’, this allows your Physician to decide if any extra screening or investigations are required.  For example if there is a strong history of bowel cancer in your family it may be necessary that you undergo screening at an earlier age that the general population.  Make sure this is not overlooked!

 General review of all the body’s organ systems

This is referred to as a systems review and aims to quickly screen all the major organs to ensure there are no early signs of disease that need further questioning or investigation.  The main systems that should be enquired about are

Cardiovascular – Any chest pains, shortness of breath on exertion, palpitations etc

Respiratory – Any shortness of breath, chronic cough, wheeze etc

Gastrointestinal – Indigestion, bowel motions, abdominal pains

Urinary – Sexual health screen, erectile function, voiding issues

Gynecological – More specific to women – Abnormal bleeding, cervical cancer screening

Skin – Any lumps, bumps or rashes

These are the main systems but there will also be several other questions that you should  be asked.

Are you a smoker?  

Smoking is something that contributes significantly to the development of several diseases and is something that should be regularly addressed.  I always make the point to ask all my patients who smoke if they are thinking of quitting every time I see them.  Even if I know they don’t want to quit I still ask as one day they may surprise me and I want to be there ready to help them.

What is your alcohol intake?

Research has shown that people consistently underestimate their alcohol intake.  A good alcohol history involves being asked exactly how much and what drink you consume each night.  Sometimes just having to think about it and say it out loud is enough to make you realize you may be drinking too much!

What do you eat on a day to day basis?  

It is vital that you let your doctor know what you are eating and not just that you think you have a healthy diet.  I see countless people who think they are on a healthy diet but are actually consuming foods that are detrimental to their health on a regular basis.  A health check is the perfect opportunity to pick up these problems and offer advice as to how to maintain a healthy diet.

Do you partake in any physical activity?

Your physical activity levels will also be ascertained as if you are not doing enough exercise your risk of cardiovascular disease may be higher and so need more attention.  If someone is not exercising I always make a point of asking why.  This isn’t so I can make them feel bad but instead so I can offer a solution if there are any particular limitations I can offer help with.

Are you happy or is there anything bothering you?

A large proportion of the population suffer from some form of mental illness and a scarily significant portion of these remain undiagnosed.  Depression, anxiety and other issues can affect anyone at any point in their life and can be significantly disabling.  Many people will not ask for help as they are scared of being judged or think they can’t be helped.  If you have any symptoms or concerns regarding mental health be sure to raise them with your doctor as there are so many ways in which we can help you and you do not need to suffer in silence.

There are several questions your Physician should ask you before they even lift up a stethoscope or pump up a blood pressure cuff.  This information is of vital importance and you should be forthcoming in all your answers.  I hope now you have a good idea of what you should expect to be asked and you could probably even think about these issues beforehand so you can answer in more detail.  If you feel that some of the information has been missed or not been enquired about during your health check, feel free to mention it or ask that it is explored.  After all it is your health that is being checked!

Once your Physician has taken a good history and listened to all your concerns, it is time to move on to the ‘physical exam and ordering of investigations’

 

The 35-45 Year-Old Health Check – (Part 1) – Why is it so important?

By Murtaza Ahmed MD 

As I mentioned in my previous post, the obesity epidemic, one of the most common presentations of the 35-45 year old  patient is for a ‘general health check’.  There is something about this age that makes people conscious that there may be aspects of their health that require attention.  The fact is that it is actually a really good time to catch this segment of the population.  I always make sure that I fully encourage those who come looking to undergo a health check, and I always take the opportunity to catch those that are passing through with other problems and use the opportunity to assess their general health.

The health check in this age group is actually of great use and importance.  Unlike health checks and screening in older age groups, this health check is primarily geared around primary prevention (prevention of disease actually developing) and early recognition of disease.  The reason this is so crucial is because at this age we can still try to prevent many diseases developing and limit development of secondary complications in newly diagnosed disease.  A while ago it was realized that the real success in medicine and healthcare was prevention of disease and at this point there was a shift away from simply treating problems towards recognizing and modifying risk factors.

This presented a great challenge to us as Physicians as it is hard to convince someone who has no symptoms that they should undergo tests and investigation.  We also met resistance from groups such as drug companies as there is little profit to be made in preventing people from needing drugs.  However those of us who were determined to ensure good health in our patients and the population as a whole recognized the importance of picking up disease early and as a result the ‘35-45 year old health check’ was born.  This check is by no means just for those between these ages, but this is just the average age where it is implemented.

Identifying risk factors at an early age before disease has developed allows us to make attempts to prevent disease development.  If cholesterol is high we can take steps to lower it, thus reducing the risk of developing coronary artery disease and stroke.  If someone is suffering from pre-diabetes we can detect this condition (which has no symptoms) and potentially reverse it before it turns into its permanent and crippling form.  If someone has high blood pressure we can take steps to ensure it is lowered and once again reduce the risk of developing cardiovascular disease and stroke.  If someone has declining renal function we can intervene and investigate early and prevent the development of chronic kidney disease.  I could go on and on, and it is for these very reasons that he ’35-45 year old health check’ is so important and should be encouraged in all those in and around this age bracket.

From the start of my career as a Physician I always realized the importance of empowering the patient.  I believe people should be educated on their own health and treatments so that they can be a part of the decision making rather than just having blind trust in us.  I have always found that if someone understands why they are doing something they are much more likely to be a part of it and adhere to any prevention or treatment plans.

It is for this reason that I am writing this article.  I want you to understand why it is that you should attend the occasional ‘general health check’ and more importantly I want you to understand what it is exactly that you should expect from your Physician.  If you go prepared you can not only ask educated questions and be ‘a part’ of the process, but you can also ensure that you have got everything you require and be reassured that you are doing the best you can for your own health.

Finding a Physician

Many people in their thirties or forties don’t actually have a regular Physician.  They may have not really suffered from any illness that required ongoing management and as such have just dropped in to random doctors when they needed something.  One of the great things about looking to get a health check is that it gives you the opportunity to find a regular Physician.  This is important as you want to see someone you can get to know and who in time will know your history.  This is vital to good patient care and you should not compromise on it.

The important thing to remember when choosing a Physician is not to settle for just anyone.  Just as there are good and bad mechanics and good and bad lawyers, there are good and bad doctors.  If you are lucky enough to have a good family Physician, great, but if not take your time to choose one.  Go by word of mouth, or try a few out.  In time we will develop a network of trusted Physicians here on myheart.net but until then do what you can to ensure you pick someone you trust and can form a comfortable doctor-patient relationship with.

Once you think you have found a Physician you should probe them to see you can trust them with assessing your overall health.  Enquire about the health check and ask what they will be looking for (don’t worry, by the end of this series you will know exactly what to expect).  Don’t be scared to ask or question, remember you are the customer and have have a choice.  If they are receptive to offering a health check and mention the important aspect then you can rest assured and move forward.  If however you do not get what you are looking for, or are told it is unnecessary then move on and find someone who has your best interests in mind.

After you have found your soon to be, if not already, regular Physician, book in for your health check and we can proceed to the first part – ‘the history’.

Stroke – Part 1 – Types of Stroke

By Julian Booker, MD

Stroke falls under the category of cerebrovascular disease meaning disease involving the blood vessels of the central nervous system (brain, spinal cord and visual system). We all know someone that has had a stroke but many of us do not know what a stroke is. I have heard people refer to strokes when stating that a person’s blood pressure was too high or as an alternative name for a heart attack or to describe a simple fainting spell. I will use this post as a venue to describe the main types of strokes. Each subsequent post will go into more detail about the respective stroke subtypes. Before we go further, if you have hypertension it is critical that you get it under control and keep it under control.

TIA

This type of event probably doesn’t deserve its own category but because of how common it is, I will separate it. TIA is short for Transient Ischemic Attack. Many times it is referred to as a mini-stroke. The TIA is characteristic of neurologic dysfunction such as weakness, slurred speech or confusion that gets better on its own. Generally these symptoms are short lived lasting less than 24 hours. More specifically, there is no evidence of any permanent brain injury on specialized brain scans such as MRI.

Ischemic

This type of stroke occurs when there is insufficient blood flow to a portion of your brain. This can happen because an artery gets clogged similarly to what happens in a heart attack. A clot or large particle can be dislodged from elsewhere in the body that travels to the brain and blocks an artery. These clots usually originate from the heart, aorta or carotid artery. It is extremely unusual for strokes to be caused from clots from elsewhere in the body because they would have to travel through your lungs, which serve as a filter. Lastly, ischemic strokes can originate from hypoperfusion or insufficient blood flow not necessarily related to a total or near-total blockage of an artery. Hypoperfusion injury of your brain happens when your blood pressure is so low that not enough blood flows to the brain matter or if the oxygen levels in your blood fall to low. When I say that your blood pressure has to be very low I mean that it is VERY VERY low. If you are awake enough to complain that your blood pressure is too low then your blood pressure is not too low. This type of injury tends to happen following cardiac arrest, drowning or other drastic events.

Hemorrhagic

The last subtype that will be included today are bleeding strokes. These bleeding strokes account for about 20% of the total number strokes annually. These strokes generally fall into one of two categories. The first is intracerebral hemorrhage (ICH) where there is bleeding directly into the brain. As the bleeding extends it damages the brain matter directly. It also increases the pressure within your skull, smashing the sensitive tissue against an unforgiving environment in the bones and dura. When the bleeding does not occur within the brain matter rather within the cerebrospinal fluid then it is classified as a subarachnoid hemorrhage.

Chronic kidney disease – Part 2 – a little more

By Julian Booker, MD

You may recall in an earlier post a discussion of Coronary Heart Disease (CHD) risk equivalency. A CHD risk equivalent is a disease or cluster of diseases that places you at a significantly increased risk for a heart attack. Your risk of heart attack is so high in fact that it may be as high as a person who has already had a previous heart attack. I will include a list of commonly accepted CHD risk equivalents:

1. Symptomatic carotid artery disease. We consider symptoms either a transient ischemic attack (TIA) or stroke felt to be caused by carotid blockages.
2. Asymptomatic carotid stenosis (blockage) of at least 50%
3. Diabetes mellitus. This becomes increasingly true as you become older and/or have had diabetes for longer periods of time.
4. Peripheral artery disease
5. Abdominal aortic aneurysm
6. A Framingham risk score of >20% which suggests that your risk of developing significant cardiovascular disease in the next 10 years is greater than 20%.

Interestingly, chronic kidney disease (CKD) seems to confer a similarly powerful risk of cardiac events. The association between chronic kidney disease and coronary disease is so powerful that some are calling for it to become our next CHD equivalent.

Do not worry. The same treatments that your physician implements to address your CKD serve a dual purpose.  There is significant overlap between the goals of care for both CKD and coronary disease prevention.

Aggressive blood pressure control

The first step will be to check your urine for certain proteins. If you are above a certain threshold, then your doctor will probably be less tolerant of any level of hypertension.  You should not have a blood pressure of higher than 140/90 mmHg and if your urine protein levels are high then we are even more strict with a target of less than 130/80.  How your physician achieves that target blood pressure is generally less important unless your protein levels are high OR if you carry a diagnosis of diabetes. In that case, an angiotensin receptor blocker such as Benicar, Micardis or Avapro is is in order. Alternatively an angiotensin converting enzyme inhibitor such as Mavik or Altace can be used. As always, the nonpharmacologic interventions are appropriate and should be used as a supplement to any prescriptions.

Cardiovascular Risk Modification

Diet and lifestyle management has always been important but is even more important at this juncture.

The American Heart Association recommends at least 30 minutes of moderate intensity exercise at least 5 days per week or 25 minutes of vigorous exercise 3 days per week (or some combination). If you are overweight, you should strongly consider a dietary program to help you lose weight. Too much salt (sodium) is bad for your blood pressure. This is particularly true when your kidney function is diminished. If you are a smoker then smoking cessation is in order. Your blood sugar must be under control consistently. The use of aspirin for primary prevention of cardiac events should at least be discussed with your physician. If you have documented coronary artery disease or a CHD equivalent, then ask your doctor about your LDL (low density lipoprotein) or bad cholesterol. A lower value, less than 100 or preferably less than 70 under the proper circumstances may very well save your life.

Medication Review

Many medications that we routinely take can be harmful to your kidneys and should only be used in moderation or not at all. Some medicines such as ibuprofen or Aleve are not expected by many patients. Some prescription medications can be problematic as well so a good relationship with your primary care physician can be invaluable.

Immunization

If you have at least moderate kidney dysfunction, then your immune system can be considered somewhat compromised. Your physician may encourage you to undergo regular immunizations.

Imaging

Specialized kidney imaging such as ultrasound can help your doctor determine nature of your kidney disease. Sometimes the cause is structural and can be corrected with a procedure.

Related articles

• Chronic kidney disease – Part 1 – The basics (myheartnet.wordpress.com)

Chronic kidney disease – Part 1 – The basics

By Julian Booker, MD

I have spent a great deal of time discussing medical conditions that directly affect your heart or are a consequence of heart disease. Today’s topic is not specifically a heart related condition but is directly related and pertinent nonetheless. The kidneys and the heart have a partnership in managing the cardiovascular system. In business terms the heart is like the chief executive officer (the BOSS,) and the kidneys are like the chief financial officers (really important but not quite as important as the CEO). Kidney doctors may argue the hierarchy but since this is my post I chose the ranking. The heart and kidneys work together to regulate blood pressure and the body’s fluid levels

Chronic kidney disease, or chronic kidney failure is a condition where your kidneys have been damaged and do not perform their primary functions at peak capacity. In addition to the aforementioned duties, the kidney’s most well-known function is to help filter the blood of various toxins and excess byproducts of metabolism.

Like other cardiovascular and related diseases such as hypertension, high cholesterol, heart failure and diabetes the onset can be insidious. Your kidneys may be failing for quite some time without you ever knowing. It is often only after developing profound kidney failure that you develop symptoms. Some symptoms to look for include:

1. Decrease in daily urine production
2. Leg or abdominal swelling
3. Persistent itching
4. Difficult to control blood pressure (hypertension)
5. Shortness of breath or symptoms consistent with heart failure
6. Weakness or fatigue
7. Sharp chest pain that tends to be worse when lying flat compared to sitting forward
8. Persistent loss of appetite

The good thing is that usually this is a progressive condition that can be detected by routine blood work. The blood urea nitrogen (BUN) and serum creatinine are our primary indicators of kidney function. From these values we can calculate a glomerular filtration rate (GFR). The GFR estimates how much blood your kidneys are able to purify in a given minute. GFR is the best metric to watch when following kidney function. Your health care professional will use the GFR to categorize your kidney disease

• Stage I: Your GFR is still normal (>90) but there is evidence in urine tests that there may be a problem
• Stage II: Your GFR is mildly decreased (60-90)
• Stage III: Your GFR is significantly reduced (30-60).  We really need to be aggressive about controlling your risk factors.
• Stage IV: GFR is 15-30. At this point you have severely reduced kidney function. We need to start making preparations for dialysis as it is imminent.
• Stage V: GFR is less than15. You have very severe kidney dysfunction and dialysis will likely be initiated soon.

But why does this belong on a heart blog? First, we are medicine doctors and concern ourselves with the whole person. Second, the heart and kidneys are more related than simply sharing a job. The disease processes that affect one will also affect the other. The two main causes of chronic kidney failure are hypertension and diabetes which are also two of the leading causes of heart disease. Persons with chronic kidney disease have a much higher risk of cardiovascular events including heart attack, stroke, heart failure, peripheral artery disease and death than the general population.

The Obesity Epidemic – Don’t Wait Until It’s Too Late

By Murtaza Ahmed MD

There is no doubt that the third, fourth and fifth decades of life are a crucial and important period of life when it comes to our health and well being.  This is the transition stage from youth to our senior years and what we do during this time plays a huge part in determining how we will spend our future years.  The way we treat our bodies during this crucial period will help determine whether we get to spend our later years enjoying the retirement we worked our whole lives for, traveling and playing with our grandchildren, or instead plagued with disease and their complications and forever struggling to maintain our independence.

The sad fact of matter is that, as doctors, whereas we used to try to prevent people from developing chronic disease in their fifties and sixties, we now find ourselves diagnosing people younger and younger and having to tell them that they may not see their children graduate college, never mind hold their grandchildren.  This has been as a result of growing levels of obesity, physical inactivity, smoking, and not taking responsibility for our own health.  Although it is never too late to make a difference to your health, it is still the fact that the earlier we intervene the greater the benefit and nothing is more true in this instance than the age old saying ‘prevention is better than cure’ (although in this case treatment is probably more fitting as there often is no cure!).

As we pass our mid twenties and begin to approach our thirties, life can start to change rapidly.  We may enter a stable job, get married and start a family.  All of a sudden we go from a more carefree existence to one where we have responsibilities and other people to take care of.  Work or careers can take the front seat and after attending to family commitments and other necessities, what little ‘free’ time we have left is spent trying to expend as little energy as possible.  This period of life can creep up on us and before we know it we find ourselves asking ourselves what happened to us?

Time and time again I am faced with patients in their early forties entering my consulting room asking me what they can do to try to regain control of their deteriorating health and wellbeing.  I am not sure what it is about turning forty, but it definitely seems to be a period of realisation for many people.  Of the people I do see, some will listen and make a change in their lives, whereas others will simply slip back into their old ways unaware that they will find themselves back in my rooms in ten years time, only this time for a diagnosis not a check up.  As I mentioned earlier, there is a great deal we can do for someone who presents in their forties, but if they had realised what was going to happen to them ten or fifteen years earlier, things would have been a lot easier.

It was previously thought that we were fairly healthy and invincible in our adolescence and twenties and only later in life would our body begin to become susceptible and succumb to the changes that lead to chronic disease, but research, medical science and epidemiology has now revealed that the changes that lead to our developing these diseases can begin in our teenage years.  This is a scary notion.  The very things that will kill us or take away our quality of life in our later years are already developing whilst we are at school.  There are many diseases that can affect us, but the main ones that are responsible for afflicting large numbers of the population are obesity, diabetes, coronary artery disease, hypertension (high blood pressure), chronic pulmonary disease (including emphysema), chronic kidney disease, peripheral vascular disease and cerebrovascular disease (cause of stroke).

This looks like a long and scary list, and it is!  Each of these diseases can be developing in us without any symptoms whatsoever, and when we finally realise, it is all too often too late.  This is one of the most scary things about chronic disease.  There can be no symptoms, signs or indications that anything is wrong.  We can float through life feeling fine and remaining blissfully unaware that the way we are choosing to live is harming us from within.

One of the biggest factors that leads to the development of chronic diseases is OBESITY.  This is the biggest health problem we face in modern times.  The population is getting heavier and heavier each year.  Obesity is dangerous because it leads to so many different health problems.  Amongst other things, being overweight increases the risk of developing diabetes, heart disease, stroke, high blood pressure and skeletal problems.  We do not currently understand all the intricate mechanisms by which obesity damages our body, but what we do know is that it definitely does.

The current school generation is suffering from an obesity epidemic in their teens, but for those who were at school prior to a decade ago the situation is somewhat different and needs to be addressed separately.  This generation grew up in an era where the obesity epidemic was in its infancy.  Most people were not overweight and remained this way after they left school and well into their twenties.  Physical activity levels were much higher as computers and TV played less of a role in peoples lives, and although many calorie rich and fast foods were around, availability was much less.  For this generation the problem is that obesity has slowly snuck up on them and incorporated itself in such a way that that it remained unnoticed for years to decades!

To understand why this happened we must explore how it is that people gain weight.  This is actually a very interesting topic and the answer is not what most people think.  If you have read my previous articles (such as Why we gain weight, What’s in my food?) you may already have an idea, and if you haven’t then I suggest you do as the information is very important.

To explain why the general population gains weight over time I will use an example of a patient I saw a few days ago.  I use him as he is a typical representation of what is happening in the population. He is 45 and came to me concerned about his weight.  To begin with I asked him to stand on the scales, and he weighed 94 kg (207 lbs) standing at 5’6” tall.  I asked him why he had come today and he told me that he was looking through his old wedding photos (aged 27) and was shocked by how different his body was then when compared to now!  I asked him how much he weighed then and he told me he was 76 kg (162.8 lbs).  The interesting point is that he had never before in the past 18 years realised how much he was changing.  He was truly amazed that he has put on 18 kg (40 lbs) and never even really noticed.

I asked him what he thought about why he had put on so much weight over the years, and his answer was the same as so many people think.  He felt that he must have just been eating too much every day over the years and that this resulted in a steady weight gain.  Whilst it is true that he probably had been eating too much on a regular basis, this in not in fact the reason he went from 76 kg to 94 kg over 18 years.

If you have read my article on energy balance and why we gain weight you will know that the human body is remarkable at keeping itself constant.  The body loves to stay the same and always tries to do so.  If we overeat by a small amount for a few days the body’s response is to reduce the appetite and under eat for similar period.  The differences are so small that we barely notice them but they are certainly occurring.  Even if your diet consists of junk, you reach a stable weight despite the fact that you are still eating junk and remain there.  The result is that over time we balance our eating to maintain our weight, and if you look at population studies it is quite clear that the weight of the population as a whole remains constant throughout the year.

So by now you are probably thinking if we don’t gain weight throughout the year, how has my patient gone from 76 kg to 94 kg!!!  The answer is that he has done it in very small, but consistent bursts.  When scientists actually sat down and studied people’s weight over years, they realised that people didn’t gain weight steadily, but instead put on the weight over very specific periods of the year.  What people were doing was eating relatively consistently over the year, but then overeating by a significant amount over important occasions such as thanksgiving or christmas before returning back to their normal eating pattern after.  The level of overeating was too overwhelming for the body and as a result it just gained weight and was unable to compensate.  After the period the body was once again able to regain control stay at the new weight until the next period of overeating.

The weight gain was so small (often less than half a kilogram) that the person wouldn’t even notice.  This pattern would be repeated year after year and the person would gain on average 1 kg (2.2 lbs) per year.  This may sound like a small amount but when you add it up year after year it becomes substantial!  If you now look back to my patient you will notice that he only gained on average 1 kg per year, but over time this resulted in a massive 18 kg!!!  Each gain was so small that he never even noticed until one day when he compared the beginning and end result.

So the problem is that people tend to let themselves go when it comes to eating once or twice a year and gain a small amount of weight, but as they don’t realise they make no effort to try to lose it.  This results in a gradual increase in weight over the years.  It is very demoralising when you find yourself 20kg heavier than you should be and losing it can be very difficult and requires time and discipline.  The earlier one realises what is happening the better and easier it is to reduce and control.  I want people to realise that by simply making the effort after each period of eating (usually only twice a year) they can prevent the massive weight gain that accompanies it over time.

The reason understanding this is so important is because one reason people don’t try to control their weight is that they think it will be too hard to permanently change their eating habits.  If however they realise that one or two small weight loss efforts a year can result in a stable weight then they will be a lot more inclined to do so and the result will be a vast improve in their health.

The reason I have placed so much emphasis on obesity is that this is one of the main drivers behind the development of chronic disease and especially diabetes!  The prevalence of diabetes is constantly increasing and the age of diagnosis is becoming younger.  As a doctor I hate nothing more than diagnosing someone, especially those who are young or have young families, with Type II diabetes.  They will often come in feeling fine with no symptoms but leave having been told they will likely develop heart disease, stroke, kidney disease, blindness, neuropathy and many more awful conditions.  When they ask what they can do to stop these things happening I have to tell them that diabetes is generally irreversible (once past a certain threshold) and that all they can do now is damage control.  Time after time I see people who wish they had realised earlier and taken steps to change their life whilst they had the chance.

Obesity is a huge problem and is the most concerning issue that is threatening the health of the developed world (and more increasingly developing nations!).  It leads to a vast array of health problems and markedly increased mortality (death) and, possibly even more concerning, morbidity (as this means more years of your life are spent in poor health).  It is during the years that people think they don’t need to worry about their health that lots of the damage is done and by the time they realise, it is often too late.  Understand why we gain weight and take the steps to rectify it early and you will reap the rewards in the future.

[ Health and wellbeing through the middle years of life is a huge topic with many avenues to explore, and something I intend to expand upon in the coming articles.  As well as discussing potential problems and their causes I will offer solutions and explain exactly how you can screen yourself and what you should ask your doctor for in a check up.  There are many issues such as smoking, salt intake and physical activity that need to be addressed and we will endeavour to do so in due course.  Here at Myheart.net we truly care about the health and wellbeing of the whole population and strive to provide you with all the necessary information to take control of your health.  Thank you for reading ]

What is a stress test?

By Julian Booker, MD

Unless otherwise stated, any stress test referenced on a MyHeart related blog post will refer specifically to cardiac stress tests.  Other heart related stress tests like cardiopulmonary exercise tests can be discussed at a later date.

In generic terms, a stress test is a procedure to indirectly determine whether there are significant blockages in your coronary arteries.

A coronary angiogram that shows the LMCA, LAD and LCX. (Photo credit: Wikipedia)

Your heart arteries will not be visualized in an isolated stress test. The goal of stress test is to identify regions of heart muscle that are starving for adequate blood flow, also called ischemia. Your physician will have several different ways to achieve this goal but all commonly used stress methods can be categorized under to broad categories. The end result of these two broad categories, increased blood flow to your hearts arteries (or sometimes lack thereof), is the key to diagnosis.

Increased Workload

The heart is the powerhouse of your body. With stress tests that increase the heart workload, the heart is forced to pump more blood each minute than at rest. The same way that your body is fueled by food, your heart is fueled by blood (queue the obligatory True Blood reference). Blood supplies nutrients such as oxygen, glucose and fatty acids to the heart. If there is a blockage in one of your heart’s arteries then any portion of your powerhouse supplied by that artery does not have access to adequate energy to perform. This results in electrical and mechanical changes that we can detect. We will discuss some of these methods in future posts.

There are two main ways that we increase your heart’s workload. The first is via exercise. The most popular method of exercise stress in most places is via the treadmill.

English: Stock footage taken at Beaumont Hospital. 14:18, 28 October 2006 (UTC) (Photo credit: Wikipedia)

Many physicians love exercise stress testing either alone or in conjunction with imaging as a stress modality of choice because it serves not only to stress the heart but also provides powerful additional prognostic information. Some places prefer to use a bicycle ergometer but the same principle applies.

For those that are unable to exercise adequately a pharmacologic or medical stress can be used instead. Intravenous infusions can simulate the effect of exercise on your heart. Dobutamine is a catecholamine that works a bit like adrenalin. It increases your heart rate and can be used in lieu of exercise.

These methods of stress are versatile. As mentioned above, when the heart rate increases sufficiency, regions of heart muscle without sufficient blood flow will struggle. The temporary changes have a formal name called ischemia. Ischemia is similar to the process that happens during angina but it takes place under safe, controlled circumstances. Active ischemia can be detected by electrocardiogram (ECG a.k.a. EKG), echocardiography, nuclear perfusion imaging, MRI perfusion imaging and CT perfusion imaging.

Vasodilators

The second broad category of stressing can be considered vasodilator testing. Vasodilators are another type pharmacologic stress agent that work differently than dobutamine.  Stress vasodilators are based around adenosine, another one of the body’s miracle substances. These agents may increase heart rate to a degree but their main action is to dilate the coronary arteries. Normal coronary arteries can drastically increase blood flow when dilated whereas diseased vessels are much less capable.

Nuclear medicine myocardial perfusion scan with Thallium-201 for the rest images (bottom rows) and Tc-Sestamibi for the stress images (top rows). The nuclear medicine myocardial perfusion scan plays a pivotal role in the noninvasive evaluation of coronary artery disease. The study not only identifies patients with coronary artery disease, it also provides overall prognostic information or overall risk of adverse cardiac events for the patient. (Photo credit: Wikipedia)

Perfusion imaging uses these differences in blood flow with vasodilation to its advantage. Blood flow in the heart muscle is then evaluated either by direct quantification or by comparison to surrounding muscle. When perfusion imaging is used in conjunction with vasodilator pharmacologic agents, your doctor will be able to identify muscle that is supplied by a severely diseased coronary artery.

Considerations before taking your stress test

You should discuss with your health care provider what medicines should be withheld prior to your stress test. Some agents like beta-blockers and certain calcium channel blockers may prevent your heart rate from increasing adequately and can make workload-type stress tests difficult. If you are having a vasodilator stress test you should withhold caffeine for several hours before hand. If you have active asthma or COPD then these medications may incite breathing difficulties. If you think you are having a heart attack or are having active chest pain, stress testing in any form is probably not the best idea.

Echocardiography – Part 2 – Transesophageal echo

By Julian Booker, MD

Transesophageal echocardiography, or TEE, is a special echo technique that your physician may request. During a TEE, the transducer is not placed on the chest but is swallowed by the patient. The probe is about the width of an average index finger but is very long.

Deutsch: TEE-Sonde (Photo credit: Wikipedia)

The probe is flexible and the tip can be manipulated using controls on the handle. The tip of the probe can move forward, backwards and to each side to obtain the best image of the heart as possible. The special conductive gel is still required so the probe will need to be coated with a thin layer. The conductive gel also serves as a lubricant to ease the passage of the probe into the esophagus.

TEE is a very safe procedure with a very low risk of complications. The risks involved are potentially be severe but are extremely rare. The procedure can be uncomfortable so it is best performed with some form of anesthesia as well as local sedation. Untoward reactions to the sedation is possible but exceedingly rare.  The risk that is most concerning is an esophageal perforation also known as a hole in the food pipe. This complication which has been reported in 1 in 5,000-10,000 patients sometimes requires surgery to fix. I have never personally had a case and I do not believe that any of my colleagues have had cases either. If your physician is experienced and careful, your risks are probably even lower than the quoted number. What you may experience is a bit of a sore throat for a few hours after the

numbing medicine wears off. The TEE probe can be irritating to your throat as it twists back and forth. Fortunately, even the sore throat is relatively uncommon.

TEE uses the same principles of sound and Doppler that the transthoracic echocardiogram (TTE) as described in the earlier post. But why would your physician order a TEE instead of a TTE? Have you ever tried to listen to a conversation in another room of your house? It is difficult to hear great distances and through walls. Now that you we understand that echocardiography is based around sound, you can imagine that it is far more difficult to listen though skin, fat, muscle, lung tissue and just to take a picture of the heart. The heart’s valves and atria (the reservoir chambers) are located very far from the optimal imaging windows for the standard echo.

TEE is most commonly used to better evaluate the heart valves particularly when trying to decide whether surgery to fix is appropriate. Other common uses include assessing the aorta size or to get a better determination of the heart’s anatomy if the TTE pictures are inconclusive. One of the commonest indications for TEE is to look for blood clots which can cause strokes. Patients with abnormal heart rhythms such as atrial fibrillation or atrial flutter may require this procedure before being brought back to a normal rhythm. If you do have a blood clot, the jolt of being returning to normal rhythm can dislodge any clots that are present.

Related articles

• Echocardiography – Part 1 – What is an echocardiogram (myheartnet.wordpress.com)