Dilated cardiomyopathy after pacemaker implantation in complete heart block

The aim of this study was to evaluate the clinical features of patients with congenital complete heart block (CCHB) who developed dilated cardiomyopathy (DCM) after pacemaker implantation (PMI) and to determine factors predicting DCM development.

A total of 15 patients were reviewed retrospectively. They were classified into two groups, one consisted of four patients who were diagnosed as having CCHB in utero or at birth and who developed DCM after PMI (DCM group) and the other consisted of 11 patients who did not (non-DCM group).

Maternal autoantibodies were found in two of the DCM group and in five of the non-DCM group. Perfusion defects in myocardial imaging were detected in all DCM patients and in five non-DCM patients. DCM developed 2 to 43 months after PMI and three DCM patients died of heart failure 7 to 48 months after PMI. In pathological studies, endocardial or interstitial fibrosis was present in all DCM patients and in one of two in the non-DCM group. No significant differences between the two groups were found in age at PMI, atrial or ventricular rate, end-diastolic dimension and ejection fraction of the left ventricle before PMI, and width of QRS after PMI.

Although it was suspected that the patients with CCHB had myocardial involvement before PMI, there was no significant factor predicting the risk of DCM after PMI. In addition to cardiac rhythm abnormalities, careful attention should be paid to cardiac function in CCHB patients after PMI.