SUNDAY MAGAZINE

Safe heart

HEALTHWATCH

Dr. T.S. KLER

SAVING LIVES: ICD performs the task of the doctor.

SAVING LIVES: ICD performs the task of the doctor.  

ICD performs the task of the doctor.

A HALE and hearty person suddenly loses consciousness and is rushed to the hospital, with his blood pressure and pulse not recordable. An electric shock is given over his chest. This timely shock provides the patient a new life.

Many may not be as fortunate. On regaining consciousness, the patient undergoes a few cardiac investigations and the diagnosis is ventricular fibrillation and the treatment defibrillation.

Ventricular fibrillation is a very rapid and chaotic rhythm originating from the lower chambers of the heart called ventricles. Unless treated promptly, it leads to sudden death. Though the patient's heart can be revived, if there's delay of more than five minutes, he may not regain consciousness. Defibrillation is a technique to bring this rhythm back to normal by applying an electrical shock over the chest with a machine called defibrillator. Everyone may not be as lucky as the patient mentioned above and may not get aid on time.

Medical Science has made this technique possible through a portable emergency room of the size of a matchbox called an Implantable Cardioverter Defibrillator (ICD), which fits into the human body with a software performing the task of the doctor.

Automatic Implantable Cardioverter Defibrillator or ICD is a device the size of a matchbox. It is implanted under the skin below the collarbone. It is connected to a thin wire called lead that is introduced into the heart through a vein. Implanted under local anaesthesia, the procedure takes about 45 minutes.

Once implanted, it keeps a strict watch over the heart rate and rhythm and gives automatic internal shocks to correct chaotic rhythms in the case of both ventricular tachycardia and ventricular fibrillation — which are life threatening arrhythmias. The life span of an ICD is seven to eight years after which a battery change is required with the lead remaining unchanged.

Sudden cardiac death is defined as death occurring within one hour of onset of symptoms. The most common cause of sudden cardiac death is ventricular fibrillation. Patients who survive such an event are called sudden cardiac death (SCD) survivors and are ideal candidates for ICD implantation.

Safe heart

It is considered the most effective method to prevent sudden death in these patients as they are at higher risk of a repeat attack of SCD, which is 35-40 per cent a year.

Many patients undergo syncope, which is a brief episode of sudden unconsciousness followed by spontaneous recovery. Normally, such patients are known to have heart disease, which is the cause for unconsciousness. They are recommended to undergo an electrophysiological study. This specific test determines whether ventricular tachycardia was an underlying reason for unconsciousness. Patients with VT should have an ICD implant.

Another large group at high risk of SCD comprises patients who have had a heart attack and who have poor pumping function (LV Dysfunction) as a result. They also benefit by ICD implant.

The effectiveness of ICD therapy in preventing SCD is unmatchable. This technique continues to save thousands of lives each year in developed countries such as the U.S. Many large multi-centre trials have proven the efficacy of ICDs.

The primary obstacle to the growth of this therapy in India is its cost — ranging from Rs. 4,00,000 to Rs. 8,00,000 depending on the model and the features available. Due to its cost, this therapy is currently accessible only to the affluent in India, whereas the number of patients who require this therapy is increasing rapidly. According to available data, only 200 patients in India receive ICD implants every year, whereas in developed countries the number is in thousands.

With the decreasing cost of the device; increasing affordability of the Indian middle class and medical insurance, this therapy is likely to become the first line therapy for people who are at risk of Sudden Cardiac Death.

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