On 29/10/21, the Indian Film industry lost another of its young and bright stars to an unexpected cardiac arrest. Puneeth Raj Kumar was only 46 years old, was a healthy fitness enthusiast and had just finished at the gym and then started complaining of intense fatigue. Unfortunately his heart then went into a very fast but ineffective rhythm called ventricular fibrillation. As no blood was being circulated by the heart, all the organs started suffocating including his brain and by the time he reached hospital it was too late and he was pronounced dead. He leaves behind a young wife and two daughters. Very much in keeping with the kind of human being he was, he had asked for his eyes to be donated in the event of his death and his brave family made sure that his wishes were respected. This is a devastating story and all we can do is wish for strength for his family to bear such a huge loss.
I wanted to do a video on sudden cardiac arrest and sudden death. I can understand that some may not want to watch this due to its content, it does have some messages that may be helpful. I dedicate this video to Puneeth and those that have been left bereft.
Sudden cardiac arrest refers to the sudden cessation of cardiac activity leading to no blood being circulated around the body. This is usually due to the heart going into an abnormal heart rhythm which results in the heart not beating at all or the heart beating so fast that it is completely ineffective. The latter is the most common heart rhythm disturbance and referred to as ventricular fibrillation. If cardiac activity is not restored in some way then inevitably this leads to death which is then termed sudden cardiac death.
Sudden cardiac death is not uncommon. It is estimated that 15% of total mortality in the western world can be attributed to sudden cardiac death. The risk of experiencing sudden cardiac arrest can be increased by a number of factors but the most important 2 are:
- Increasing age
- Underlying cardiac disease (which may be congenital or acquired).
In general sudden cardiac arrest is seen 2-3x more commonly in men compared to women. If there is a history of clinically recognised heart disease (congenital heart disease, angina, previous heart attacks, cardiomyopathy and heart failure) then there is 6-10 fold increased risk of SCD. In addition if patients don’t have known heart disease but have major risk factors for heart disease then the risk is increased by 2-4x. SCA is the mechanism of death in 60% of patients with known coronary heart disease and it is the initial clinical manifestation in approximately 15% of patients.
What are the causes of sudden cardiac arrest?
Broadly speaking the causes of sudden cardiac arrest can be divided into 4 groups.
- Ischemic heart disease (70%) – This is where for some reason the blood supply to the heart is interrupted. The most common reason is plaque in the heart arteries but other ways by which the blood supply may be interrupted due to a blood clot going down the coronary arteries, or spasm of the arteries or even dissection of the arteries.
- Non-ischemic heart disease (10%) This is where the heart itself. for some reason is weakened or damaged either due to a congenital problem, inherited cardiomyopathy (hypertrophic cardiomyopathy), valvular disease, myocarditis or aortic dissection
- No structural heart disease (10-12% of patients under age 45)- This is where the heart itself looks ok and the arteries are not diseased. In these cases the cause is some form of electrical problem. This includes long QT syndrome, Brugada syndrome, heart block, and familial sudden death.
- Non-cardiac causes – this includes pulmonary embolism, intracranial haemorrhage, drowning, central airways obstruction or even drug or toxin induced.
In general, in patients above the age of 35, the likeliest causes will be coronary artery disease whereas in patients under the age of 35, it is more likely due to either a congenital cause or one of the other non ischemic causes i have discussed.
Whilst there may be a substrate, there have to be some triggers which make the event happen at that particular time. Common triggers include ischemia, electrolyte disturbances (low potassium/low magnesium), medications (which may have proarrhythmic effect), stress, fever, dehydration, intercurrent illness, extreme exertion and sleep disturbances.
Patients may get warning symptoms beforehand but they are generally mild and non-specific and therefore not uncommonly patients don’t seek medical attention. In one particular study, up to 51% of patients had some form of warning within 4 weeks of the event and upto 80% may have a warning within an hour of the event. These warnings include chest pain, breathlessness, palpitation, lightheadedness or blackouts. Usually chest pain and breathlessness are the commonest symptoms.
Active smokers are at more than double risk of sudden cardiac arrest compared to non-smokers. Fortunately the risk declines rapidly once one stops smoking.
The risk of SCA is transiently increased during and upto 30 minutes of very strenuous exercise but the actual risk is very low (1 per 1.5 million episodes of exercise). This risk is greater during unaccustomed exercise compared to accustomed exercise. The only thing to take note of is that strenuous exercise in someone with unrecognised heart disease such as cardiomyopathy is higher.
Family history of sudden cardiac arrest:
A family history especially at a young age will almost double the risk. In addition if there are other risk factors such as smoking etc then the risk can go up 2-5 fold. I certainly feel that everyone should be curious about their family history and those that do have a family history of SCA should be investigated aggressively.
Patients with chronic inflammation as measured by CRP also seem to be at increased risk.
Heavy alcohol consumption (>6 drinks a day) is a risk factor
Excessive stress can definitely be a risk factor and we see the risk of SCA go up in stressful situations like war or earthquakes
The single most important thing in sudden cardiac arrest is resuscitation and electrical shock treatment. This is why I think one of the most important things that everyone can learn is the ability to carry out CPR and deliver defibrillation. Most places now have a defibrillator and it is vital that all employers and schools teach how to deliver safe and effective defibrillation.
In patients with an elevated risk of sudden cardiac arrest such as patients with heart disease, screening is generally recommended. In the general population, it is not offered because it is generally not cost-effective in terms of identifying patients at high risk of sudden cardiac arrest. However if it was me, I’d at least have an ECG, echocardiogram and a stress test or cardiac CT.
Many people ask me why despite all the tests some people can still suffer a cardiac arrest and there are several reasons as to why:
- As doctors we tend to be a little limited by what we know. This means that we sometimes disregard the fact that there is so much we don’t know. Although we have lots of tests to study the heart, most of them rely on the visual appearance of the heart. A heart may look normal but may still be composed of abnormal muscle which we may have inherited and unless we do a biopsy, we would not know that it was abnormal.
- Unfortunately most of what we know about sudden cardiac arrest has come from studying survivors. The study of the dead is usually poorly done. I was speaking to a histopathologist and he was telling me that most post-mortems are just done to exclude the possibility of foul play and often there is no really detailed assessment of the heart. This is partly due to lack of time, funding and expertise. Unless we start investing in the study of the dead, we will not make strides in understanding sudden cardiac death. We also need to be doing many more post-mortems to improve our learning.
This brings me to the end of a somewhat depressing video. In my 30 years in medicine, I have come to realise one thing and that is that something bad can happen to anyone anytime. No one is immune. Whilst this awareness may enslave us and fill us with fear, we can also use this awareness to liberate us into living a more fulfilling life. No one has any control over how long they will live however we do have some control over how we choose to live. When we live in harmony with others, live a life of giving and compassion, simplicity and moderation and spend time with our loved ones, we experience joy and truthfully as long as we strive to achieve this, nothing else matters.
I wish you all good health and a lot of joy.
Here is a link to the video: