Nonresponse to Cardiac Resynchronization Therapy High, Poorly Managed

Cardiac Resynchronization Therapy Pacemaker vs Medical Therapy
Cardiac Resynchronization Therapy Pacemaker vs Medical Therapy
The incidence of patients who are not responsive to cardiac resynchronization therapy was found to be high.

The incidence of patients who are not responsive to cardiac resynchronization therapy (CRT) was found to be high, according to a study published in the Journal of the American College of Cardiology.

Researchers evaluated participants who received CRT devices between January 2013 and November 2015 at 69 centers worldwide (n=1524). The total number of patients evaluated after study withdrawal, death, or missed 6-month follow-up was 1327. Eligible patients were enrolled ≤30 days following the successful implant with any market-approved Abbott CRT pacemaker or CRT defibrillator device with quadripolar LV leads.

Study sites recorded baseline patient demographics, clinical characteristics, comorbidities, guideline-directed medical regimens and antiarrhythmic drugs, and system implantation details. All patients were followed either remotely via telephone, or in-office every 3 months for 1 year. CRT response status was assessed once at the in-office 6-month follow-up visit. Response to CRT was determined using the clinical composite score (CCS) and by site-specific definition, based on each site’s standard clinical care assessments and functional tests for CRT response.

The incidence of site-defined black of response to CRT was 20%, based on clinical events and clinical functioning assessments, and 31%, based on objective CCS score. Site-defined nonresponders received treatment more often than responders (55.9% vs 38.3%, respectively; P <.001), primarily consisting of medication changes (36.1%) and heart failure education (36.6%). At the 6-month follow-up, 44.1% of patients classified as nonresponders by site-specific definition (n=105 of 238) received no additional treatment.

This study was limited by the use of a registry protocol that did not mandate baseline data collection, and by the fact that lead positions varied across sites. In addition, CCS scoring was limited in that a single hospitalization event for heart failure could qualify a patients as nonresponsive, and in that observations related to temporal profiles, frequency, and duration of heart failure hospitalizations were not captured in this scoring system.

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“In a diverse international, contemporary cohort, patients treated with CRT were sicker/more challenging with a large contingent that remained non-responders, who were mostly passively managed and remained at risk,” the researchers concluded. “Non-responders require rigorous attention to accurate diagnosis (which may be facilitated by an objective assessment such as CCS), follow-up intensification and integration with cross-disciplinary care, and exploration of effective interventions. This is an unmet need among high-risk heart failure patients.”

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.


Varma N, Boehmer J, Bhargava K, et al. Evaluation, management, and outcomes of patients poorly responsive to cardiac resynchronization device therapy. J Am Coll Cardiol. 2019;74(21):2588-2603.