Defibrillator implant can reduce heart failure risk

AN ADVANCED defibrillator implant normally used to treat people with severe heart failure can significantly reduce symptoms in patients with mild cardiac problems, a study has found.

The research, published recently in the New England Journal of Medicine, found heart failure devices called CRT-Ds, which combine simple defibrillator technology with a pacing mechanism, reduced the risk of “heart-failure events” by more than 40 per cent in patients at the early stages of the disease.

The finding, which is the culmination of a four-year trial on 1,820 patients with moderate cardiomyopathy (heart muscle disease), has significant therapeutic implications for the treatment of heart failure – which is estimated to affect around 40,000 people in Ireland and cause some 12,000 hospital admissions each year.

Heart failure, often mistakenly used to describe heart attack or cardiac arrest, occurs when the heart’s ability to pump blood through the body becomes impaired.

Although the term suggests a sudden or abrupt stop, heart failure usually develops slowly, often over years, as the heart function gradually diminishes.

Patients may not become aware of the problem until symptoms appear years after the process has begun.

The condition can, in many instances, be caused by a general impairment of the heart muscle.

Patients with severe forms of the condition – those with symptoms at rest or as a result of minimal exertion – can be fitted with cardiac resynchronisation therapy defibrillators (CRT-Ds).

These implants are used to resynchronise the complex contractions of the heart’s ventricles by sending small electrical impulses through the heart muscle.

The implant also contains a defibrillator to quickly terminate an abnormally fast, life-threatening heart rhythm which can result in sudden cardiac death.

The latest research, conducted by a research team based at the University of Rochester in New York at 110 centres worldwide, indicates the devices may significantly slow the progression of the disease in patients with minimal symptoms who would normally be treated less effectively with drugs, such as beta blockers.

Medical director of the Irish Heart Foundation and consultant cardiologist, Brian Maurer, said the study bears out the theory that by pacing the heart in “the appropriate sequence over time”, the heart muscle can remodel itself and improve overall function.

Dr Maurer said: “We have known for some years that cardiac resynchronisation therapy is very useful in patients with severe symptomatic heart failure.

“The latest research appears, if confirmed, to extend the criteria for treatment to patients who are not severely symptomatic but who have significant cardiac dysfunction even though it is not affecting their day-to-day existence to the same extent,” he said.

The CRT-Ds devices used in the trial were manufactured by Boston Scientific at its Clonmel plant.