Clinical study on pacing-induced cardiomyopathy resulting from long-time right ventricular apical pacing in pacemaker-dependent patients

AIM:To evaluate the prevalence of pacing-induced cardiomyopathy (PiCMP) resulting from long-time right ventricular apical pacing (RVAP) in pacemaker-dependent patients. METHODS: Clinical data of patients with prolonged pacing from the apex of the right ventricle were analyzed retrospectively. Inclusion criteria were right ventricular apex stimulation for at least 2 years, pacemaker dependency and absence of structural heart disease at the time of initial implantation. PiCMP was pre-defined as left ventricular ejection fraction (LVEF)≤45%, dyskinesia during RV pacing and absence of other known causes of cardiomyopathy. All patients were examined by echocardiography and their plasma brain natriuretic peptide (BNP) levels were detected. All patients underwent 6-min walking test (6MWT) to assess the exercise capacity and quality of life was assessed using the Minnesota Living with Heart Failure Questionnaire (MLHFQ). RESULTS: Fifty-five patients from our Outpatient Department met the inclusion criteria. PiCMP was diagnosed in eight patients (14.5%). Echocardiography showed significant LV remodeling in PiCMP patients ［LVEF (41.2±4.4)%, LV end-diastolic diameter (LVEDD) (55.3±3.2) mm］ compared with that in patients with preserved LVEF ［LVEF (62.3±6.5)%, P<0.05, LVEDD (45.2±4.1) mm, P<0.05］. No significant differences were found in age, gender, duration of RV pacing, heart rate, interventricular mechanical delay, QRS duration and arterial hypertension between groups. Exercise capacity, quality of life and plasma BNP level of PiCMP patients were lower than those of patients with preserved LVEF. CONCLUSION: The prevalence of PiCMP is remarkably low, but PiCMP could severely affect the quality of life. PiCMP is associated with pronounced LV remodeling resulting from RVAP.