Nearly half of patients with ICDs receive first appropriate therapy within 7 years
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Key takeaways:
- Almost half of patients with first-time implantable cardioverter defibrillators had appropriate therapy within 7 years.
- The findings suggest the devices benefit the patients they are indicated for.
Among patients who received an implantable cardioverter defibrillator, nearly half received appropriate therapy within 7 years, indicating the benefit of the technology in guideline-indicated patients, researchers reported.
For an analysis presented at Heart Rhythm 2023, the researchers assessed time to first shock, antitachycardia pacing or any therapy in 225,444 real-world contemporary patients (mean age, 63 years; 72% men) who received a single- or dual-chamber ICD and were included in the CareLink database of Medtronic device recipients from 2013 to 2022.
“We wanted to see in a contemporary cohort exactly how often defibrillators were treating patients for ventricular arrhythmias,” Anne B. Curtis, MD, SUNY Distinguished Professor in the department of medicine, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, told Healio. “Most of them were put in for primary prevention on the thought that the patient may have an arrhythmia, so we wanted to see today how often is that actually happening.”
At 7 years, 45% of first-time ICD recipients had received appropriate therapy (39% received antitachycardia pacing and 32% received an appropriate shock), according to the researchers.
In patients with a primary prevention indication, 43% received appropriate therapy within 7 years (37% received antitachycardia pacing and 30% received an appropriate shock), whereas in patients with a secondary prevention indication, 56% received appropriate therapy within 7 years (49% received antitachycardia pacing and 39% received an appropriate shock), Curtis and colleagues found.
“To find out that 45% of these patients actually had an arrhythmia over a 7-year period is pretty high,” Curtis, who is past president of the Heart Rhythm Society, told Healio.
The most common detection zone was ventricular tachycardia (62.6%), followed by ventricular fibrillation (27.9%) and fast ventricular tachycardia (9.5%), according to the researchers.
Because the CareLink database cannot distinguish between appropriate and inappropriate shocks, the researchers used data from the PainFree SmartShock Technology (PF-SST) trial to impute appropriate therapy rates using statistical modeling. Based on that analysis, the estimated rate of episodes classified as inappropriate therapy was 7% (compared with 5.8% from PF-SST), and the estimated rate of inappropriate therapy at 1 year was 2.5% (compared with 2% from PF-SST), according to the researchers. The area under the curve for the model was 0.7.
“This tells us that it’s a good thing these patients have their devices in,” Curtis told Healio. “The electrophysiology community can do a better job of communicating these facts: Patients do wind up using these devices pretty often. We need to continue to utilize this therapy in patients who meet our current guidelines.”