Sinus Bradycardia and Multiple Episodes of Sinus Arrest With Lasting Period of More Than 14 Seconds Following Administration of Metoprolol: A Case Report

Abstract An aged male patient with coronary heart disease which had been treated with coronary artery bypass grafts (CABG) and administration of metoprolol, presented paroxysmal vertigo in the previous three weeks. The 24 hours synchronic 12-lead dynamic electrocardiography (DCG) revealed many episodes of sinus arrest which mostly were followed by A-V junctional or ventricular escape rhythm, the longest sinus pause lasting more than 14.5 seconds with no symptom. After withdrawal of metoprolol, the DCG revealed much less episodes of sinus arrest than on-admission, but still some A-V junctional and ventricular escape beats. Sick sinus syndromes was then diagnosed, and a synchronous dual-chamber pacemaker (DDDR) was implanted two weeks after admission.