ABC | Volume 110, Nº1, January 2018

Original Article Correlation of Electrocardiographic Changes with Cardiac Magnetic Resonance Findings in Patients with Hypertrophic Cardiomyopathy Gabriela Miana de Mattos Paixão, Horácio Eduardo Veronesi, Halsted Alarcão Gomes Pereira da Silva, José Nunes de Alencar Neto, Carolina de Paulo Maldi, Luciano de Figueiredo Aguiar Filho, Ibrahim Masciarelli Francisco Pinto, Francisco Faustino de Albuquerque Carneiro de França, Edileide de Barros Correia Instituto Dante Pazzanese de Cardiologia, São Paulo, SP – Brazil Mailing Address: Gabriela Miana de Mattos Paixão • Rua Maranhão, 1567/302. Postal Code 30150-331, Funcionários, Belo Horizonte, MG – Brazil E-mail: gabimiana@gmail.com, luciamianapaixao@gmail.com Manuscript received January 17, 2017, revised manuscript September 05, 2017, accepted September 12, 2017 DOI: 10.5935/abc.20170189 Abstract Background: Electrocardiogram is the initial test in the investigation of heart disease. Electrocardiographic changes in hypertrophic cardiomyopathy have no set pattern, and correlates poorly with echocardiographic findings. Cardiac magnetic resonance imaging has been gaining momentum for better assessment of hypertrophy, as well as the detection of myocardial fibrosis. Objectives: To correlate the electrocardiographic changes with the location of hypertrophy in hypertrophic cardiomyopathy by cardiac magnetic resonance. Methods: This descriptive cross-sectional study evaluated 68 patients with confirmed diagnosis of hypertrophic cardiomyopathy by cardiac magnetic resonance. The patients’ electrocardiogram was compared with the location of the greatest myocardial hypertrophy by cardiac magnetic resonance. Statistical significance level of 5% and 95% confidence interval were adopted. Results: Of 68 patients, 69% had septal hypertrophy, 21% concentric and 10% apical hypertrophies. Concentric hypertrophy showed the greatest myocardial fibrosis mass (p < 0.001) and the greatest R wave size in D1 (p = 0.0280). The amplitudes of R waves in V5 and V6 (p = 0.0391, p = 0.0148) were higher in apical hypertrophy, with statistical significance. Apical hypertrophy was also associated with higher T wave negativity in D1, V5 and V6 (p < 0.001). Strain pattern was found in 100% of the patients with apical hypertrophy (p < 0.001). Conclusion: The location of myocardial hypertrophy by cardiac magnetic resonance can be correlated with electrocardiographic changes, especially for apical hypertrophy. (Arq Bras Cardiol. 2018; 110(1):52-59) Keywords: Hypertrophic cardiomyopathy / genetic; Electrocardiography; Magnetic Resonance Spectroscopy. Introduction Hypertrophic cardiomyopathy (HCM) is an autosomal dominant disease, characterized by myocardial hypertrophy in the absence of cardiac or systemic diseases. 1 In adults, the diagnosis is defined by a diastolic thickness of any ventricular wall ≥ 15 mm measured on any imaging test. 2 Electrocardiogram (ECG) is the initial test to be performed when investigating heart diseases. In HCM, the ECG has not a defined pattern, and can show signs of left ventricular overload, presence of q waves, changes in the ST segment, abnormal T waves, or be even normal in 6% of the patients. 3 Some specific electrocardiographic findings may suggest the location of hypertrophy, as well as the presence of fibrosis. Giant inverted T waves (> 10 mm) in the precordial or inferolateral leads suggest apical involvement. Deep q waves in the inferolateral leads with positive T waves are associated with the asymmetric distribution of the HCM, and q waves lasting more than 40 ms relate to fibrosis. The ST-segment elevation in the lateral wall can correlate to small apical aneurysms, which are associated with fibrosis. 2 Electrocardiographic patterns similar to that of myocardial infarction in young individuals can precede the echocardiographic evidence of myocardial hypertrophy. 4 The electrocardiographic changes can lead to the suspicion of HCM, and together with the clinical history and other imaging tests can establish the diagnosis. Traditionally, echocardiography is the imaging test of choice to diagnose HCM, because of its wide availability and lower cost. However, the relationship between the electrocardiographic changes and the morphology and severity of myocardial thickness has not been well established when assessed on the echocardiogram. 5,6 Cardiac magnetic resonance imaging has gained importance in the HCM assessment, because of its superiority in measuring the thickness of ventricular walls, mainly in regions difficult 52