Cardiac Resynchronization Therapy Improves Left Ventricular Function in PICM

Left ventricular (LV) function and functional capacity are improved with cardiac resynchronization therapy (CRT) among patients with pacemaker-induced cardiomyopathy (PICM). These findings were published in the International Journal of Cardiology.

Patients with a pacemaker were enrolled in a registry between 2017 and 2021 at the Pacemaker and ICD Center in Germany. Patients with PICM without poorly treated cardiac comorbidities had cardiac medication optimized over 3 months. Those with persistent LV ejection fraction (LVEF) of less than 40% and a New York Heart Association (NYHA) functional class of II or worse after optimization were offered CRT upgrade (N=55). The outcomes of this study were changes to LV systolic volume (LVESV), LVEF, and NYHA functional class at 6 months. Response to CRT was defined as LVESV decrease of 15% or more from baseline.

Of note, 81 patients were not eligible for CRT upgrade due to coronary heart disease requiring intervention (39.5%) and the need for optimization of antihypertensive medication (54.3%). An additional 9 eligible patients did not receive CRT upgrade due to improved LVEF and 2 eligible patients did not consent to surgery.

The included patients had a mean age of 75±11.3 years, 80% were men, the average LVEF was 31.5%±5.4%, 67.3% had NYHA functional class III, and 25.4% had comorbid atrial fibrillation.

During the CRT upgrade, 98.2% of patients had successful LV lead implantation, 87.3% received CRT pacemaker, and most leads were placed laterally (38.1%) or posterolaterally (32.7%).

The only CRT complication was 1 infection event, in which a patient developed a pocket hematoma on day 6 after upgrade which became infected. Ultimately, the entire aggregate and electrodes were removed.

At 6 months after CRT upgrade, LVESV improved to 75.9 ml from 101.6 ml at baseline (P <.001), LVEF improved to 46.1% (P <.001), and the proportion of patients with NYHA functional class III decreased to 24% whereas the proportions with class II increased from 37% to 64% and class I from 0% to 12% (P <.001).

The overall response rate was 83.6% and no mortality events occurred.

The major limitation of this study is the small sample size, despite 4 years of enrollment.

“…in typical patients at an outpatient clinic CRT upgrade performed by an implanter with sufficient experience improves left ventricular function and functional capacity and is associated with an acceptable complication rate,” the study authors wrote. “With careful indication, CRT upgrade for PICM is therefore recommended in these patients.”