Implantable Cardioverter Defibrillator (ICD) device meant to prevent sudden cardiac arrest (SCA) in high risk patients globally has now evolved into being used as a MRI compatible device in India. Every year approximately 400 devices are implanted in India to prevent SCA. This device is also implanted as primary prevention of SCA.
A small device that's placed in the chest below the collar bone, ICD automatically monitors your heart rhythm and delivers therapy as required to prevent SCA. "The device uses electrical pulses or shocks to control life-threatening, irregular heartbeats, especially those that could cause SCA. The advantage of MRI compatible ICD is that patient can undergo MRI scan in any part of the body safely, " explains Dr AM Karthigesan, consultant cardiac electrophysiologist at Apollo Hospital, Chennai.
SCA is among the most common causes of death throughout the world. It is estimated that more than 3 million people die yearly from SCA, with a survival rate of less than 1 per cent. In fact, SCA claims one life every two minutes, taking more lives each year than breast cancer, lung cancer, or AIDS. About two-thirds of the time, sudden cardiac death among the younger population is due to a heart abnormality.
SCA can happen in people who appear healthy and have no known heart disease or other risk factors. It sometimes occurs without any warning making time the prime determinant of survival in patients experiencing SCA. Frequently, the warning signs and symptoms of a heart condition in youth go undetected or are misdiagnosed. Most people who have SCA die from it—often within minutes.
Rapid treatment of SCA with a defibrillator can be lifesaving. A defibrillator is a device that sends an electric shock to the heart to try to restore its normal rhythm. Automated external defibrillators (AEDs) can also be used by bystanders to save the lives of people who are having SCA. Having an implanted medical device, such as a pacemaker or implantable cardioverter defibrillator can do the needful. These devices help control abnormal heart rhythms.
Many times people are not able to understand the difference between heart attack and SCA. Heart attack is caused by blood clot formation in the coronary arteries which not necessarily lead to sudden death. SCA happens when the heart beats very fast and erratic and then stops in few minutes. Most common causes for SCA are myocardial infarction, severe left ventricular dysfunction (LVD) and genetic conditions. Left ventricular dysfunction (LVD) with subsequent congestive heart failure (CHF) constitutes the final common pathway for a host of cardiac disorders.
Most of the ICD recipients are severe LV dysfunction patients either due to previous heart attack or cardiomyopathy. Many of LV dysfunction patients had undergone coronary revascularization procedures like CABG surgery or Angioplasty. "Coronary artery disease (CAD) is very common in India and patients should be educated about importance of monitoring LV function after coronary event or subsequent to coronary revascularization. Those who continue to maintain low ejection fraction (<35 per cent) should be advised to undergo primary prevention ICD implantation. Unexplained syncope (loss of consciousness) with underlying LV dysfunction is one of the warning symptoms of SCA," concludes Dr Karthigesan.