ABC | Volume 110, Nº1, January 2018

Original Article Paixão et al Correlation of ECG with RM in hypertrophic cardiomyopathy Arq Bras Cardiol. 2018; 110(1):52-59 to visualize on echocardiography, in addition to providing ventricular morphology and function assessment. Detection of delayed contrast-enhancement has prognostic value. 2 This study was aimed at correlating electrocardiographic variables with the location of myocardial hypertrophy assessed on cardiac magnetic resonance imaging. Methods This is a descriptive cross-sectional study that assessed patients diagnosed with HCM and followed up at the Cardiomyopathy Sector of the Instituto Dante Pazzanese de Cardiologia (IDPC), who underwent cardiac magnetic resonance imaging from January 2012 to September 2015. The patients’ inclusion criteria were: age over 18 years and diagnosis of HCM confirmed on interpretable ECG and magnetic resonance imaging performed at the Imaging Sector of the IDPC. The exclusion criteria were: age < 18 years; ejection fraction lower than 50% on cardiac magnetic resonance imaging; resistant arterial hypertension; presence of coronary artery disease, characterized by a coronary lesion greater than 50% on angiography; presence of Chagas disease; previous diagnosis of amyloidosis; endomyocardial fibrosis; Fabry disease; presence of definitive pacemaker; and septal myectomy or alcoholization prior to cardiac magnetic resonance imaging. The HCM database of the Cardiomyopathy Sector of the IDPC was analyzed, and the medical records of 112 patients meeting this study inclusion criteria, which were stored at the Sector of Medical File and Statistics (SAME) of the IDPC, were assessed. After reviewing the medical files, 44 patients were excluded from the study. The ECGs previously performed for the outpatient clinic visit at the Cardiomyopathy Sector were reviewed by the chief of the Tele-Electrocardiography Sector of the IDPC, in accordance with the 2016 Brazilian Guidelines on ECG Analysis and Report. 7 The ECG report comprised the following variables: rhythm, heart’s QRS axis, ventricular and atrial overloads, intraventricular blocks, presence of strain, R wave size (millimeters) in leads DI, V1, V5 and V6, and T wave size (millimeters) in leads D1, V5 and V6. Cardiac magnetic resonance imaging was assessed by the Radiology Team of the IDPC regarding the location of myocardial hypertrophy, based on the segmentation proposed by the American Heart Association, 8 and the presence of delayed enhancement, as well as quantification of the fibrosis mass in grams. The 17 segments were grouped into five regions: anterior, inferior, lateral, septal and apical. (Figure 1) Patients with hypertrophy > 15 mm in at least three of those regions were considered to have concentric hypertrophy. (Figure 2) Statistical analysis The electrocardiographic variables previously described were compared with the region of hypertrophy, the presence of delayed enhancement and the amount of fibrosis identified on cardiac magnetic resonance imaging. Normality of the data was assessed by use of Kolmogorov‑Smirnov test, and nonparametric tests were used to compare between the groups. The summary measures median and 25th and 75th percentiles were calculated for the continuous variables, and nonparametric Kruskal-Wallis test was used to check the statistical significance between the groups, followed by two-by-two comparisons (Dunn’s multiple comparison test). For attribute variables, the results were presented as percentages and frequency. Fisher-Freeman-Halton exact test was used to assess the statistical significance between the groups. Statistical significance level of 5% and 95% confidence interval were adopted. The findings were recorded in an electronic spreadsheet of Microsoft Office Excel , version 2013e, and the Statistical Package for the Social Sciences (SPSS), version 21.0 for Windows®, was used for analysis. Figure 1 – Left ventricular segmentation proposed by the American Heart Association. LEFT VENTRICULAR SEGMENTATION REGIONS 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 ANTERIOR INFERIOR APICAL SEPTAL LATERAL 53