Dr Siddhant N Yadav › ICD
ICD implantation in Andheri East
A defibrillator inside the chest, for people at risk of a dangerous fast rhythm — it watches continuously and treats within seconds.
What an ICD is
An implantable cardioverter defibrillator looks similar to a pacemaker and is placed the same way, under the skin below the collarbone. It does everything a pacemaker does, and one thing more: if the heart goes into a dangerously fast rhythm — ventricular tachycardia or ventricular fibrillation — it treats it immediately, either with rapid pacing the patient does not feel, or with an internal shock.
These rhythms are the mechanism behind most sudden cardiac deaths. They give no warning and there is no time to reach a hospital. An ICD is the only treatment that is present at the moment it happens.
Who it is for
Secondary prevention
For people who have already survived a cardiac arrest, or had a sustained dangerous rhythm. Here the risk is proven, and an ICD is standard.
Primary prevention
For people who have not yet had such an event but whose risk is high — most often a weak heart muscle, with an ejection fraction of 35% or less, after a heart attack or from cardiomyopathy. Also considered in certain inherited conditions such as hypertrophic cardiomyopathy, long QT syndrome, Brugada syndrome and ARVC.
Deciding this well requires accurate measurement, not estimation. Ejection fraction from a good echocardiogram, and often cardiac MRI, which measures function precisely and shows scar in the muscle. Scar is where dangerous rhythms start, and seeing it changes risk assessment in a way that echo alone cannot.
How an ICD differs from a pacemaker
- A pacemaker treats a heart that is too slow. An ICD also treats a heart that is dangerously fast.
- An ICD contains a pacemaker within it, so it covers both.
- An ICD is physically slightly larger, and battery life is shorter.
- A CRT-D adds a third lead to resynchronise a heart whose walls contract out of step — used in selected patients with heart failure.
Living with an ICD
Most people never receive a shock. Those who do describe it as a sudden hard thump in the chest — brief, startling, and over in an instant. It means the device did exactly what it was implanted to do.
After a shock, contact the clinic. A single shock with quick recovery needs a non-urgent check; repeated shocks need immediate attention. The device stores a recording of every event, so what happened can be read directly at follow-up.
There are driving restrictions after an implant and after any shock. These vary and must be discussed individually — please ask rather than assume.
This page is general information about a treatment or test. It is not medical advice for your situation, and it cannot replace an examination and a conversation with a doctor who knows your history.
Common questions
Does the shock hurt?
People who have felt one describe a sudden strong thump in the chest lasting a fraction of a second. It is startling rather than prolonged. Many episodes are treated by rapid pacing instead, which is not felt at all.
Will I definitely get shocked at some point?
No. A large proportion of patients never receive a therapy. The device is insurance against an event that may never come — but which would otherwise be unsurvivable.
Can the ICD be switched off later?
Yes. The shock function can be deactivated, which is sometimes appropriate in end-of-life care. It is a considered decision made together with you and your family.
What should I do if I get a shock?
One shock and you feel well: contact the clinic the same day for a device check. More than one shock, or you feel unwell after it: treat it as an emergency and get to hospital.
Why do I need an MRI before deciding on an ICD?
Because the decision hinges on how weak the heart muscle is and how much scar it contains. Cardiac MRI measures both accurately. Scar tissue is where dangerous rhythms originate, so seeing it directly refines who genuinely benefits.
Book an appointment
Nanak Heart Clinic, Raja Cottage, Sahar Road, Koldongri, opposite ICICI Bank, Andheri East, Mumbai 400069. Monday to Saturday, 7–9 pm.