Cardiac Magnetic Resonance as a diagnostic tool in arrhythmias. (24th May 2021) - Caldeira Da Rocha, R
Abstract: Funding Acknowledgements: Type of funding sources: None. Introduction: Etiology of cardiac arrhythmias is often difficult to determine.As the gold standard to anatomical and functional cardiac evaluation, Cardiac Magnetic Resonance(CMR)can be a fundamental technique for accurate assessment of myocardial arrhythmic substrates or for arrhythmias management. Purpose: The aim of this study is to determine diagnostic and arrhythmic risk stratification impact of CMR performed in patients with suspected or confirmed arrhythmias. Methods: We performed a six-years prospective study of patients with suspected or confirmed arrhythmias which evaluation with other techniques did not provide a definitive diagnosis.These patients underwent CMR for diagnostic and risk stratification assessment.We applied a protocol to evaluate both ventricles' morphology and functional and late gadolinium enhancement (LGE) presence. Results: A total of 93 patients were included, of which 66% were male, with a mean age of 45 ± 17 years old. The indications for patients with suspected or confirmed arrhythmias performing CMR evaluation were the following: 33% (n = 31) of the patients had very frequent premature ventricular complexes, 23% (n = 21) had sustained ventricular tachycardia (VT), 5%(n = 5) non-sustained VT, 17%(n = 16) suspected structural heart disease with high arrhythmic potential, 10%(n = 9) unexplained recurrent syncope, 9 %(n = 8) supraventricular tachycardia and 3% (n = 3) aborted sudden cardiac death. Depressed ejection fraction (EF)(<50%) was present in 10% (n = 9) for LV(mean EF 38 ± 9%) and 15%(n = 14) for RV (mean EF 42 ± 7%). Dilation of LV was found in 25% of patients (n = 23, mean LV volume: 115 ± 7ml/m²), with RV dilation being present in only 1 patient, who had right ventricle arrhythmogenic dysplasia (RVAD) (RV volume: 152ml/m²). In total, 16%had interventricular septum hypertrophy (mean 15 ± 4mm/m2).We found slight anterior leaflet prolapse of mitral valve in 10% (n = 9) of the cases and mild mitral regurgitation in 15% (n = 14). Left atrium dilation was observed in 17% (n = 16) of patients (mean area of 18 ± 2cm2/m2), as right atrium was dilated in only two. In 20% of the patients, CMR contributed to establish a previously unknown diagnosis: 6% (n = 5) have hypertrophic cardiomyopathy, 4%(n = 4)a myocarditis sequelae and 2%(n = 2)had RVAD. LV non-compaction, a silent myocardial infarction scar and non-ischemic dilated cardiomyopathy were diagnosed in 3%of the cases each. In 15%(n = 14)we found nonspecific variations, which deserve follow-up. On the remaining patients, CMR was considered normal. Conclusion: As a high reproducible, accurate and versatile technique, CMR allowed an increase on diagnosis in 20% of the patients with suspected or confirmed arrhythmias. Consequently, it contributed to the risk stratification of our study population with suspected high arrhythmic potential when the first-line complementary exams were inconclusive.