CONGRESS ABSTRACT

BACKGROUND: Bidirectional ventricular tachycardia is a rare form of ventricular tachycardia that shows dual QRS morphologies alternating beat-to-beat. First reported as a complication of digoxin treatment, then in other conditions including myocarditis, sarcoidosis, catecholaminergic tachycardia, and Andersen-Tawil syndrome, rare are the cases in acute myocardial ischemia. We present a case of 69 years old men, dyslipidemic, with an acute coronary syndrome in 2020, treated with PTCA and stent on left anterior descending artery, coronary angiography showed residual subcritical stenosis of left main. At electrocardiogram presence of left bunble brabch block (LBBB). After one year a stress myocardial scintigraphy was performed, stopped at 90% of maximal heart rate, without symptoms; during recovery phase after 22 seconds a wide QRS (170ms) tachycardia with morphology LBBB began (Figure 1), without symptoms, spontaneously interrupted after 50 s. After one minute another wide QRS tachycardia started, bidirectional (Figure 2), with interruption after 40 s. The patient did not present troponin elevation, not alteration in blood tests. No other arrhythmias were recorded, only bradycardia without pauses, shorts episodes of atrial fibrillation. Echocardiography confirmed left ventricular ejection fraction 40%. The results of myocardial scintigraphy was only fixed basal septal ipoperfusion, confirmed by the presence of late enhancement on cardiac MRI. Coronary angiography showed distal left main stenosis involving interventricolar anterior artery origin, treated with PTCA + stent. In the following months, given reduction in NYHA class, brady-tachy atrial arrhythmic disease, left ventricular ejection fraction 35% and poor chances of drug therapy, ICD CRT was implanted. At 2-year follow-up no more ventricular arrhythmias were recorded. CONCLUSIONS. Point of interest of this case is appearance of two complex different ventricular arrhythmias in the recovery phase of the stress test with paucisymptomatic patient and no arrhythmias during exercise test. The origin mechanism probably involves triggered activity from after-depolarizations, abnormal automaticity, and reentry. The fixed hypoperfusion area on myocardial scintigraphy and septal scar on cardiac MRI can be involved in the genesis of the bidirectional ventricular tachycardia; complete resolution of the arrhythmias after coronary revascularization, support ischemic hypothesis for the origin of arrhythmias.