ABC | Volume 110, Nº6, June 2018

Original Article Is There any Relationship Between Myocardial Repolarization Parameters and the Frequency of Ventricular Premature Contractions? Kayihan Karaman, 1 Metin Karayakali, 1 Arif Arisoy, 1 Ilker Akar, 2 Mustafa Ozturk, 3 Ahmet Yanik, 4 Samet Yilmaz, 1 Atac Celik 1 Gaziosmanpasa University Faculty of Medicine, Department of Cardiology, 1 Tokat - Turkey Gaziosmanpasa University Faculty of Medicine, Department of Cardiovascular Surgery, 2 Tokat - Turkey Erzurum Territorial Training and Research Hospital, Cardiology Clinic, 3 Erzurum - Turkey Samsun Training and Research Hospital, Cardiology Clinic, 4 Samsun - Turkey Mailing Address: Kayihan Karaman • Gaziosmanpasa University School of Medicine Training and Research Hospital, 60100, Tokat - Turkey E-mail: drkkaraman55@gmail.com , kay55han@hotmail.com Manuscript received June 19, 2017, revised manuscript October 18, 2017, accepted October 18, 2017 DOI: 10.5935/abc.20180079 Abstract Background: Ventricular premature contractions (VPCs) may trigger lethal ventricular arrhythmias in patients with structural heart disease. However, this role of VPCs in healthy people remains controversial once that not enough clinical trials are available. Recently, some myocardial repolarization markers, such as Tp-e interval, Tp-e/QT, and Tp-e/QTc ratios, have been reported to be useful for predicting lethal ventricular arrhythmias in various clinical disorders without structural heart disease. Objective: In this study, we aimed to investigate the relation between VPC frequent and myocardial repolarization markers in individuals without structural heart disease. Methods: Thisstudyincluded100patientswhohadcomplaintsofdizzinessandpalpitations.Twelve‑leadelectrocardiography and 24-hour ambulatory Holter recordings were obtained from all patients. VPC burden was calculated as the total number of VPCs divided by the number of all QRS complexes in the total recording time. P-values < 0.05 were considered significant. Results: Tp-e interval and Tp-e/QTc ratio were significantly higher in patients with higher VPC burden than in patients with lower VPC burden, and a positive correlation was found between these markers and VPC burden. Tp-e ( β = 1.318, p = 0.043) and Tp-e/QTc ( β = -405.136, p = 0.024) in the lead V5 were identified as independent predictors of increased VPC burden. Conclusions: Tp-e interval and Tp-e/QTc ratio increased in patients with high VPC number. Our study showed that VPCs may have a negative effect on myocardial repolarization. This interaction may lead to an increased risk of malignant arrhythmias. (Arq Bras Cardiol. 2018; 110(6):534-541) Keywords: Ventricular Premature Complexes; Arrhythmias, Cardiac; Electrocardiography / methods; Cardiovascular Diseases; Obesity; Ventricular Dysfunction, Left. Introduction Ventricular premature contractions (VPCs) are commonly seen in the electrocardiography (ECG) of patients with hypertension, obesity, and structural heart disease. Some studies reported VPCs to occur in about 4% of the general population. 1,2 As some patients may be asymptomatic, many patients suffer from VPC-related symptoms, such as palpitation, dizziness, dyspnea, and chest pain. In addition to these symptoms, frequent VPCs may causemore serious disorders. Recent studies on adults with frequent VPCs (>20,000/24 h) have reported left ventricular dilation and/or dysfunction, 3,4 diastolic dysfunction, 5 and malignant ventricular arrhythmias in patients with structural heart disease. 6 However, whether frequent VPCs are associated with malignant arrhythmias in individuals without structural heart disease remains uncertain. T wave is commonly used in assessing myocardial repolarization. Increased transmural dispersion of myocardial repolarization in a normal heart is associated with their tendency toward cardiac arrhythmias. Recently, some myocardial repolarization markers, such as QT interval (QT), corrected QT (QTc), QT dispersion (QTd), Tp-e interval (Tp-e), and Tp-e/QT ratio have been found to be useful in predicting life-threatening cardiac arrhythmias in several clinical disorders without structural heart disease. Some studies showed that increased Tp-e, Tp-e/QT, and Tp-e/QTc were related to the elevated risk of occurrence of malignant ventricular arrhythmias. 7,8 In this study, we investigated the relation between VPC burden and myocardial repolarization by using some ECG markers in individuals without structural heart disease. 534