Chronology of cardiac dysfunction after permanent pacemaker implantation: an observational 2 year prospective study in North India

The purpose of this study is to evaluate cardiac functions using transthoracic echocardiography, change in lead parameters and electrocardiogram (ECG) morphology in patients undergoing permanent pacemaker implantation over a follow-up period of 6 months. This is a prospective study in patients undergoing permanent pacemaker implantation in a tertiary care hospital. Patients undergoing permanent pacemaker implantation were enrolled for up to one year and Echocardiographic parameters (by 2 blind operators) and ECG parameters were recorded at admission (within 24 h), before discharge (within 7 days of pacemaker implantation), after 1 month (± 7 days) and after 6 months (± 7 days) of follow-up. A total of 96 patients (60.4% males and 39.6% female, mean age 66.65 years) were implanted with permanent pacemaker. The mean QRS duration was 133.18 ms and increased significantly to 146.03 ms by 6 months despite septal lead placement in majority (92%) of patients. The mean baseline ejection fraction of 51.47 decreased significantly to 47.83 by 6 months. Diastolic parameters like left atrial volume index, early to late diastolic transmitral flow velocity (E/A) and early diastolic mitral annular tissue velocity (E/e′) showed a significant increase (> 5%) from baseline by the end of first week. By the end of first month, systolic dysfunction of RV sets in with significant (> 5%) change from baseline in parameters like Right ventricle myocardial performance index, transannular plane systolic excursion and right ventricle systolic excursion velocity (RVS′). We have observed that pacemaker recipients with baseline reduced left ventricle (LV) systolic functions perform significantly worse compared to those with baseline normal cardiac functions and had a higher rate of deterioration of LV function. RV dysfunction is the first abnormality that occurs, by 1 week followed by LV dysfunction which starts by 1 month and the diastolic dysfunctions precede the systolic dysfunction. QRS duration also showed a gradual increase despite septal lead placement in majority (92%) and lead parameters showed no significant change over 6 months.