Sinus arrest following right coronary artery stent implantation

Sinus arrhythmias may occur during acute myocardial infarction involving the right coronary artery (RCA) [1,2]. They are usually transient sinus bradycardia and do not frequently cause hemodynamic instability [3]. We report a rare case of sinus arrest caused by sinus node (SN) artery occlusion following RCA stenting.A 56-year-old woman with a significant history of RCA stenosis with prior bare metal stenting, hypertension, diabetes, dyslipidemia, smoking, and paroxysmal atrial fibrillation presented to the emergency department with anginal chest pain. Initial work up showed significant elevation of cardiac troponin T with T-wave inversion in the inferior leads. She subsequently underwent cardiac catheterization. Coronary angiography revealed a 90% stenosis of the midportion of RCA with patent stent at distal portion of RCA (Figure 1, 2) and only mild disease in left anterior descending coronary and left circumflex coronary arteries. An everolimus-eluting stent, 2.5 mm × 23 mm, was placed in the stenosis of midportion of RCA. Immediately after these interventions, thrombus developed and occluded SN artery. It originated from the proximal one third portion of RCA. Electrocardiographic monitoring showed junctional escape rhythm without P waves at a heart rate of 30 beats/min, suggesting sinus arrest (Figure 3). To prevent severe bradycardia and hypotension, transvenous temporary pacemaker was placed. The patient remained asymptomatic and without hypotension. The clot in the SN artery was identified and thrombectomy was performed. Within five minutes after intervention, Thrombolysis In Myocardial Infarction (TIMI) flow 3 was observed in the SN artery within 5 minutes and the transvenous temporary pacer was removed. Electrocardiogram revealed persistent junctional escape rhythm for 5 days after revascularization, with restoration of sinus rhythm on the sixth day. Heart rate showed a gradual improvement and the patient maintained a stable heart rate at 60 beats per minute