Pacemaker associated reduction of left ventricle systolic function

In recent years, data have been accumulated on the negative effect of right ventricular (RV) stimulation, leading to left ventricular (LV) asynchrony, proarrhythmias and progressive heart failure (HF). On the other hand, biventricular pacing has been shown to affect ventricular asynchrony, reduce HF manifestations, and improve prognosis in patients with LV dysfunction and wide QRS complex. The induced asynchrony from apical right ventricular pacing is unequivocally associated with changes in myocardial perfusion, LV dysfunction, and poorer prognosis for patients over time. This has led researchers for decades to look for an alternative position for electrode placement. The incidence of pacemaker-induced cardiomyopathy (PICM) ranges from 5.9 to 39% in patients with RV pacing, depending on the given definition and the limit for the degree of pacing. Upgrading to biventricular pacing has been shown to reverse the cardiomyopathy. Recently, there has been evidence of a positive effect of His bundle pacing (HBP) in the treatment of PICM even in patients with no improvement after biventricular pacing. The question about the pathogenetic mechanisms of PICM is currently unanswered. The connection between electrical asynchrony and the negative effect on cardiac pump function is clear. There is also evidence of an established relationship between asynchrony and coronary blood flow. The predisposing individual characteristics of the patient in which these negative effects are manifested are not clear. This is an issue that requires further studies.