Pacing-induced cardiomyopathy in patients with right ventricular stimulation for >15 years.

Aims: The prevalence of pacing-induced cardiomyopathy (PiCMP) has been reported to be 9% 1 year after implantation. As long-term data are sparse, the aim of our study was to evaluate the prevalence of PiCMP in a cohort of patients with at least 15 years of right ventricular (RV) pacing.

Methods And Results: Inclusion criteria were RV stimulation for at least 15 years due to atrioventricular block III° and absence of structural heart disease at the time of initial implantation. All patients were examined by echocardiography and spiroergometry. Pacing-induced cardiomyopathy was pre-defined as left ventricular (LV) ejection fraction (LVEF) ≤45%, dyskinesia during RV pacing and absence of other known causes of cardiomyopathy. Twenty-six patients from our outpatient department met the inclusion criteria. Pacing-induced cardiomyopathy was diagnosed in four patients (15.4%). Echocardiography showed significant LV remodelling in PiCMP patients [LVEF 41.0 ± 4.5%, LV end-diastolic diameter (LVEDD) 54.0 ± 2.7 mm] compared with patients with preserved LVEF (LVEF 61.2 ± 5.8%, P = 0.002, LVEDD 45.6 ± 4.0 mm, P= 0.004). There were no significant differences regarding age, gender, duration of RV pacing, heart rate, interventricular mechanical delay, QRS duration or prevalence of sinus rhythm, and arterial hypertension between both groups. The longest intraventricular delay was significantly shorter in patients with preserved LVEF (65.5 ± 43.0 ms) compared with PiCMP patients (112.5 ± 15.0 ms, P= 0.043). Exercise capacity and quality of life did not differ significantly between both groups.

Conclusion: Considering the very long duration of RV stimulation in our study population (24.6 ± 6.6 years), the prevalence of PiCMP was remarkably low. Pacing-induced cardiomyopathy was associated with more pronounced intraventricular dyssynchrony.