P454 ARRHYTHMIC RISK AND REPOLARIZATION ALTERATIONS ON THE ECG UNCOVERED BY AN ISOPRENALINE TEST

Abstract

Abstract A 62–year–old man came to our attention for a syncopal episode that occurred during a competitive race, without prodromes, lasting a few seconds, with total, spontaneous regression and without issues. On ECG sinus bradycardia, HR 46/min and QRS fragmented in V1. During monitoring were documented many polymorphic premature ventricular complex (PVC) and polymorphic nonsustained ventricular tachycardia (NSVT). Coronary angiography showed normal coronary arteries. The Isoprenaline test was performed (intravenous infusion of Isoprenaline 0.2 mg in 100 ml of physiological solution at variable speed until obtaining a HR increase of at least 20% compared to baseline). As HR increased, a clear epsilon wave in V1 became evident. Also documented numerous polymorphic PVC and polymorphic NSVT. Cardiac magnetic resonance (MRI) was performed with documentation of findings suggestive of primary cardiomyopathy with biventricular phenotypic expression with a clear left prevalence. All these elements placed the patient at high arrhythmic risk. An implantable cardiac defibrillator was then performed. The isoprenaline–induced increase in heart rate made the epsilon wave manifest, which is an expression of an extremely delayed depolarization caused by the fibroadipose replacement of portions of the myocardium (as documented by cardiac MRI). It was also possible to exclude a J–wave syndrome in which the alterations are of repolarization and are due to the epi–endocardial electrical gradient which increases and becomes more evident at lower heart rates. The test with isoprenaline has therefore allowed us to distinguish depolarization disorders from repolarization disorders and to direct us towards the former.