Malfunctions in implanted heart defibrillators (ICD) and pacemakers were directly responsible for 61 deaths out of about 3 million implants between 1990 and 2002, showed a US Food and Drug Administration (FDA) study released on Friday.

The study noted an increase in the ICD malfunction rate during the period, while a decline for the pacemakers.

From 1990 to 2002, the annual ICD malfunction replacement rate was 20.7 per 1,000 implants, compared with 4.6 replacements per 1000 implants for pacemakers, the FDA said in a statement.

It is noticed that the ICD malfunction replacement rate trended down during the first half of the 1990s but increased during the latter half.

More than 50 percent of the ICD malfunctions occurred during the last three years of the study.

The increase in malfunctions of heart defibrillators may be a result of "increased complexity of these devices, manufacturing challenges posed by device complexity, or increased reporting by physicians", said the FDA.

The FDA said the study highlights the need for careful monitoring of device performance, and that it has begun to improve pre and post-market regulation of heart defibrillators and pacemakers.

The US health watchdog agency said it is now considering if it is necessary to demand additional information from manufacturers, and is planning for more effective communications with physicians and patients when problems arise.

Source: Xinhua