Permanent Pacemaker Timing Dilemma in Recovered Lymphocytic Myocarditis.

BACKGROUND

The timing of permanent pacemaker implantation in myocarditis-related complete heart block remains challenging because no established criteria exist for reversibility of the conduction system.

CASE SUMMARY: A previously healthy 50-year-old Asian woman presented with lymphocytic myocarditis complicated by cardiogenic shock and complete atrioventricular block (CAVB). Despite successful hemodynamic stabilization with Impella CP support and complete recovery from left ventricular dysfunction, CAVB persisted. A permanent pacemaker was implanted on day 28. Afterward, cardiac enzymes and left ventricular function remained normal, and follow-up cardiac magnetic resonance showed no myocardial edema or late gadolinium enhancement. However, CAVB remained.

DISCUSSION: This case demonstrates dissociation between cardiac recovery of systolic function and conduction system recovery in myocarditis. Despite complete normalization of all conventional indicators, conduction impairment persisted, highlighting the complexity of permanent pacemaker timing decisions.

TAKE-HOME MESSAGES: Cardiac functional recovery does not always correlate with conduction system recovery in myocarditis. Comprehensive evaluation is essential for permanent pacemaker timing decisions.