P5644Cardiac MRI for a better identification of structural heart disease in patients with ventricular arrhythmia

Abstract

Background:Ventricular arrhythmia (VA) is a quite prevalent diagnoses in the general population and the majority of patients have non-repetitive ectopic beats. However in Europe and North America, 50-100/100000 sudden unexpected cardiac deaths occur every year, and about half of these are attributable to VA. Prognostic stratification is the main issue in this setting and the presence of structural heart disease is one of the most important determinants of poor prognosis. Echocardiography is the most commonly used tool to determine the presence or the absence of structural heart disease. Aim of this study is to evaluate whether in patients with VA and normal echocardiography, cardiac MRI may identify patients with structural heart disease whose risk has been underestimated by transthoracic echocardiography. Material and Methods:From a registry of patients undergoing to cardiac MRI for VA we identified 756 consecutive patients who had an echocardiography performed in our Institute before MRI without abnormal findings. For every patient traditional risk factors and the presence of cardiovascular symptoms (chest pain, syncope, pre-lypotimia, dyspnea, palpitations) were evaluated. Ventricular ectopic beats (VEBs) was graded as follow:>1000 VEBs/24h;>10000 VEBs/24h; non-sustained ventricular tachycardia (NSVT); sustained ventricular tachycardia (SVT) and history of resuscitated cardiac arrest. End-point of the study was the presence of structural heart disease at cardiac MRI. Results:We enrolled 756 patients (mean age 42616 years; male n=481; 64%) with VA and normal 3rd level transthoracic echocardiogram who underwent cardiac MRI. Among them, 185 patients (24.5%) were found to have structural heart disease at cardiac MRI. More specifically, 69 (37.3%) patients had a diagnosis of previous myocarditis, 40 (21.6%) of arrhythmogenic right ventricular cardiomyopathy, 36 (19.5%) of dilated cardiomyopathy, 16 (8.6%) of previous myocardial infarction, 8 (4.8%) of congenital heart disease, 8 (3.7%) of hypertrophic cardiomyopathy, 5 (2.7%) of left-dominant arrhythmogenic cardiomyopathy and 3 (1.6%) of left ventricular non-compaction cardiomyopathy. In the entire cohort, 501 (66.3%) reported cardiovascular symptoms; more specifically 78 subjects (10.3%) had syncope and 102 (13.5%) had chest pain. For what concern ventricular arrhythmia, 433 patients (57.3%) had more than 1000 VEBs/24h, 199 (26.3%) had more than 10000 VEBs/24h, 173 (22.9%) had NSVT, 58 (7.7%) had SVT and 11 (1.5%) had resuscitated cardiac arrest. Among clinical variable only previous TVS (OR 2.01 95%CI 1.15-3.52) and reported chest pain (OR 2.7 95%CI 1.78-4.26) are associated with cardiac MRI positive for structural heart disease. Conclusion:Among patient with ventricular arrhythmia and normal transthoracic echocardiogram almost 25% had cardiac MRI positive for structural heart disease. Of note, among clinical variable previous chest pain and SVT were associated to positive cardiac MRI.