Topic: Sudden Cardiac Death

Speaker: Padma Shri Dr Mohsin Wali, Senior Consultant, General Medicine, Sir Gangaram Hospital, New Delhi

4th February, 2023, Saturday; 9.30-10.30am

• Cardiac arrest is occurring more frequently now than what has been seen in the past.
• Sudden cardiac death (SCD) occurs without warning without the person feeling any signs that something is about to happen. It is an unexpected death due to cardiac causes that occurs in a short period of time, generally within 1 hour of onset of symptoms, in a person with known/unknown cardiac disease.
• Patients at risk of SCD may have prodromes of chest pain, fatigue, palpitations and other nonspecific complaints, which are ignored.
• SCA is not synonymous with acute heart attack. SCA does not give time, only 10 mins or less, while acute heart attack gives time for revascularization.
• Nearly two-thirds of cardiac arrests occur as the first clinically manifested event or in the clinical setting of known disease in the absence of strong risk predictors.
• Less than 25% of the victims have high risk markers based on arrhythmic or hemodynamic parameters.
• General patterns of increased risk during the morning hours, on Mondays, and during the winter months have been described.
• SCA is not a random event. Most victims do have heart disease or other health problems often without being aware of it.
• SCD kills ~800,000 persons each year.
• Around 75% of people who die of SCA show signs of a previous heart attack and 80% have signs of CAD. Almost 92% of those who experience SCA do not survive.
• SCA kills more than 1000 people a day or one person every 90 seconds.
• In the young, it may be caused by a genetic disease.
• The incidence of SCD increases markedly with age regardless of sex or race. Sudden deaths are however more common in the younger age group.
• CHD is the most common substrate underlying SCD.
• Genetic conditions also predispose to the risk of SCD. These include genetically based primary arrhythmia disorders such as Brugada syndrome, congenital long QT interval syndrome, short QT syndrome or catecholaminergic polymorphic VT/VF, inherited structural disorders with arrhythmic SCD risk such as hypertrophic cardiomyopathy, RV dysplasia/cardiomyopathy and genetic predisposition to induced arrhythmias and SCD precipitated by drugs and electrolyte imbalance.
• Risk factors of SCD include genetic factors, CHD risk factors, arrhythmias, nutritional, psychosocial and biomarkers.
• 22 people will have died from SCD during this talk, some of them children.
• Public awareness is of utmost importance. Public should be aware of the benefits of exercise, at the same time also be aware of too much exercise, including unsupervised exercise, especially after Covid.
• Prevention of SCD requires a global approach.
• In the young, the usual causes are myocarditis, hypertrophic cardiomyopathy, long QT syndrome, Brugada syndrome, anomalous coronary artery. In the older age group, the usual causes are coronary atherosclerosis, dilated cardiomyopathy, valvular heart disease, infiltrative heart disease.
• Risk factors are different in males vs females. In the males, CAD is seen in 80% and dilated cardiomyopathy in 10%. Among females, CAD is 45%, dilated cardiomyopathy in 19% and VHD in 13%.
• The annual incidence of SCA in India is 0.55 per 1000 population. It accounts for >50% of CV deaths in India. The peak age of SCA occurrence is now between 25 and 75 years. The survival rate of SCA is less than one percent (Fortis Hospital, statistics).
• A study conducted in South India found that SCD contributed to 10% of overall mortality. On average, SCD cases were 5-8 years younger compared to the western population.
• Some risk factors are common to both CHD and SCD. These include nonmodifiable risk factors (age, family history of CHD, male gender, genetic factors) and modifiable risk factors such as smoking, hyperlipidemia, obesity, sedentary lifestyle, hypertension, diabetes and renal dysfunction).
• An LVEF of less than 30% - due to any cause – is the single most powerful independent indicator for SCD.
• PVCs and nonsustained VT during both the exercise and recovery phases of a stress test are predictive of increased risk. Arrhythmias in the recovery phase appear to predict a higher risk than arrhythmias in the recovery phase. A frequency cut off of 10 PVCs/hour as a threshold level for increased risk is cited by most studies.
• ECG markers include elevated resting heart rate, prolonged QRS duration, anormal heart rate recovery, prolonged QT interval and early repolarization syndrome.
• Increased consumption of n-3 PUFAs is associated with SCD to greater extent than nonfatal MI.
• Heavy alcohol consumption (>5 drinks per day) is associated with increased risk of SCD.
• High magnesium diet is associated with low risk of SCD.
• Psychosocial factors such as depression, low socioeconomic status, anxiety, social isolation, psychological stress have been linked to increase in CV mortality. Post covid these factors have become important.
• Some biomarkers act as risk factors. These include inflammatory markers (CRP, fibrinogen, IL-6), metabolic markers (aldosterone, renin, cystatin C, vitamin D and PTH) and neurohormonal markers (BNP/NT-proBNP).
• Prevention of sudden death in the young adult should focus on evaluation for causes known to be associated with sudden unexplained death e.g., primary arrhythmia in those <35 years, with an emphasis on atherosclerotic coronary disease in those ≥35 years of age.
• Everyone must know the correct technique of doing CPR.
• Portable defibrillators must be kept at public places.
• In Singapore, 1000 SCDs occur every year and postmortems show that 80% are CAD.
• In India, many people are unaware of preexisting heart disease. 
• In India, there are more cases of wide QRS complex, cardiomyopathies, post-scarring, arrhythmias.
• Autopsies are not usually done in India. But they should be made compulsory in people who die unexpectedly.
• People with triple vessel disease and previous myocardial scarring may have sudden CV event.
• The incidence of arrhythmia is higher after Covid than what it used to be.
• Holter monitoring must be encouraged. Its importance must be explained to the patient. It must be repeated when its next due.
• When athletes suffer a blunt trauma to the myocardium, the impact may be severe enough to provoke cardiac arrhythmia. This is called cardiac concussion or commotio cordis and is an important cause of SCD. It hits at a specific part of the cardiac cycle (just before the T wave peak).
• Heart attack, PE/DVT, arrhythmias have increased post-Covid.
• Watch out for unexplained tachycardia, breathlessness, headache (pointing to hypertension). These may be early warning signs which are ignored.
• Careful history taking and exploration of cardiorespiratory symptoms is important.
• If there is bradycardia and the patient is not on any beta blocker then explore the history. 
• Investigations can miss a finding which a patient’s history can tell us.
• Many patients need calibration of antihypertensive medication with change in season.
• Valvular heart disease, rheumatic heart disease, rheumatic carditis, myocarditis are still prevalent in India. 
• Obesity in the young is also a risk factor. History of snoring could be a sign of arrhythmia. A history of ectopics is also a risk factor.

Participants

Member National Medical Associations

Dr Yeh Woei Chong, Singapore, Chair of Council CMAAO

Dr Wasiq Qazi, Pakistan, President CMAAO

Dr Marthanda Pillai, India, Member World Medical Council, Advisor CMAAO

Dr Angelique Coetzee, South Africa

Dr Akhtar Hussain, South Africa

Prof Ashraf Nizami, Pakistan

Invitees

Dr Russell D’Souza, Australia UNESCO Chair in Bioethics

Dr Monica Vasudev, USA

Prof Arun Jamkar

Dr Apurba Krishna

Dr Kanan Sanghvi

Dr EC Ng

Dr Michael Liu

Dr Manisha Kukreja 

Dr Ramachandra Malajure

Dr TM Agrawal

Dr AC Sreeram

Dr Dinesh Reddy Sagam

Dr Kiran Garg

Dr Anjali Agarwal

Dr Bimla Kapoor

Dr Surya Raju

Dr S Sharma, Editor IJCP Group

Moderator

Mr Saurabh Aggarwal