CardioExchange Archive

Pamela Peterson and Frederick Masoudi discuss findings from their research group’s registry study, published in JAMA, suggesting that primary-prevention patients without a pacing indication derive no more clinical benefit from dual-chamber ICDs than from single-chamber devices in the year after implantation. CardioExchange’s Nihar Desai conducted the interview.

THE STUDY

The researchers retrospectively analyzed data from about 32,000 patients in the National Cardiovascular Data Registry who had received an implantable cardioverter-defibrillator (ICD) for primary prevention but did not have a pacing indication: 38% had a single-chamber device, and 62% had a dual-chamber device. One year after implantation, the two groups did not differ significantly in their rates of death, all-cause hospitalization, or hospitalization for heart failure. Complications were significantly more common with dual-chamber than with single-chamber devices. (For CardioExchange’s complete news coverage of the study, click here.)

THE AUTHORS RESPOND

Desai: Why were you interested comparing outcomes with single- versus dual-chamber devices?

Peterson and Masoudi: Several observations prompted our study. First, up to two thirds of patients with left ventricular systolic dysfunction who receive an ICD for primary prevention and do not have a pacing indication receive dual-chamber devices. Second, marked geographic variation exists in the use of dual-chamber ICDs, unrelated to patient characteristics. Third, little evidence supports the use of dual-chamber ICDs for primary prevention, and current practice guidelines are not explicit about which type of device should be used.

Desai: What implications do your findings have for providers and payors and, perhaps, for the possibility of developing a performance metric?

Peterson and Masoudi: Dual-chamber ICDs, despite their greater complexity and cost, did not improve mortality or hospitalization rates and, in fact, were associated with higher rates of complications than single-chamber devices. Those findings do not support the routine use of dual-chamber devices for primary prevention in patients who have no pacing indication. Admittedly, we don’t yet know whether dual-chamber devices limit the need for device revision and for ICD therapies. Without that evidence yet in hand, it is difficult to justify the widespread use of dual-chamber devices in patients without clear indications for pacing. Given the substantial variation in their use and the lack of evidence of benefit, this appears to be an excellent opportunity for a performance metric.

Desai: How do you envision national registries and clinical trials complementing each other to answer clinically relevant questions?

Peterson and Masoudi: Clinical trials elucidate the efficacy of a therapy in ideal populations. Registries complement clinical trials by providing information about real-world practice patterns. In particular, registries reveal who is receiving specific therapies for what indications — and what the patients’ outcomes are. In addition, some clinical questions will never be addressed by a clinical trial, and registries may be the only source of data to answer them.

Share your observations about dual-chamber ICD use in clinical practice. Does this new study change your perceptions?