Periodic repolarization dynamics may predict ICD outcomes
FROM THE ESC CONGRESS 2019
Their interest in periodic repolarization dynamics arises from increasing evidence that sympathetic mechanisms play a key role in malignant tachyarrhythmias (J Clin Invest. 2005;115:2305-15). They described periodic repolarization dynamics as a “marker of electric instability,” and noted that previous studies have shown a link between increased periodic repolarization dynamics and sudden cardiac death and adequate ICD interventions.
The study noted that more than 100,000 ICDs are implanted in the EU each year at a cost of €2 billion (U.S. $2.2 billion, Europace. 2017;19[suppl 2] ii1-90), but that a 2016 study showed that prophylactic ICD treatment may only benefit select patient subgroups (N Engl J Med. 2016;375:1221-30). While the EU-CERT-ICD supports primary prophylactic ICD therapy as the standard of care for patients with ischemic or nonischemic cardiomyopathy and reduced left ventricular ejection fraction, the invasive nature of ICD implantation carries with it risk of complications.
In an invited commentary, Sana M. Al-Khatib, MD, of Duke University, Durham, N.C., provided some context in interpreting the substudy results, noting, among other considerations, the study’s observational nature, exclusion of almost 40% of potentially eligible patients, and its omission of data for sudden cardiac death (Lancet. 2019 Sep 2. doi: 10.1016/S0140-6736[19]31956-7).
“Periodic repolarization dynamics are not yet ready for prime time,” Dr. Al-Khatib said. The group’s findings need to be validated by other studies, and a reproducible approach to measuring periodic repolarization dynamics should be established, he said. “Until such results are available, periodic repolarization dynamics are unlikely to gain traction as a test that can be consistently used to select patients for primary prevention of sudden cardiac death with ICDs.”
Dr. Bauer and Dr. Al-Khatib had no relevant financial relationships to disclose.
SOURCE: Bauer A et al. Lancet. 2019 Sep 2. doi: 10.1016/S0140-6736(19)31996-8.
