A 52 y/o male presented to the ED with worsening chest pain, palpitations and lightheadedness for one week. His past medical history is significant for hyperlipidemia and type 2 diabetes mellitus. His physical examination was unremarkable. His initial electrocardiogram showed ventricular tachycardia at 218 beats/min (fig.1). He spontaneously converted to normal sinus rhythm and was started on amiodarone drip. He continued to have 5-6 beat of ventricular tachycardia. His subsequent EKG depicted a sinus rhythm with ST elevation in leads II, III, aVF, and ST depression in v1, v2, and v3 (fig.2). His troponin level was 0.348 ng/mL. He went into sustained ventricular tachycardia again and was given 150 mg amiodarone bolus. He continued to have episodes of ventricular tachycardia lasting from 30 seconds to 1 minute. When the ventricular tachycardia persisted, he was administered 100 mg of intravenous lidocaine, which helped. A repeat dose of 100 mg lidocaine was given. He was taken for cardiac catheterization emergently, which showed an 85% stenosis of the obtuse marginal branch of the left circumflex artery. The lesion was stented with no intra-operative complications. His echocardiogram showed an LVEF of 60% with no wall motion abnormalitis, LVH and stage 1 diastolic dysfunction. The amiodarone drip was discontinued. It was felt that the likely cause of sustained ventricular tachycardia was ischemia. He was started on aspirin, ticagrelor, atorvastatin, lisinopril and metoprolol. He had no further episodes of ventricular tachycardia during his hospital stay.
Discussion:
The incidence of sustained ventricular arrythmias is about 10.2% during an acute ST elevation MI. The frequency of ventricular arrhythmias increases with the duration of ischemia. They are caused by local electrolyte abnormalities during ischemia and activation of the sympathetic nervous system and elevation of cathecholamines. Ischemic ventricular arrhythmias require prompt and adequate revascularization therapy with initiation of secondary preventive therapies, such as statin, dual antiplatelet therapy, angiotension-converting enzyme inhibitors, and beta blockers.
Conclusions:
When ventricular arrhythmias present as initial symptoms of acute coronary syndrome, a rapid identification of the underlying cause is required as immediate reperfusion therapy prevents morbidity and mortality, since anti-arrhythmic agents have a limited role in management.