The QT Interval Is Associated With Incident Cardiovascular Events

Abstract

Background Prolonged heart rate-corrected QT interval on the electrocardiogram (ECG) is associated with increased risk of myocardial infarction and cardiovascular disease (CVD)-related death in patients with prevalent coronary heart disease (CHD). Objectives We sought to examine the prognostic association between the baseline QT interval and incident cardiovascular events in individuals without known prior CVD. Methods The corrected baseline 12-lead ECG QT interval duration (QTcorr) was determined by adjustment for age, sex, race/ethnicity, and RR interval duration in 6,273 participants in the Multi-Ethnic Study of Atherosclerosis (MESA). Cox proportional hazards models adjusting for demographic and clinical risk factors were used to examine the association of baseline QTcorr with incident cardiovascular events. Results The mean age at enrollment was 61.7 ± 10 years, and 53.4% of participants were women. Cardiovascular events occurred in 291 participants over a mean follow-up of 8.0 ± 1.7 years. Each 10 ms increase in the baseline QTcorr was associated with incident heart failure (HR, 95% confidence interval (CI): 1.25 [1.14 to 1.37]), CVD events (HR, 95% CI: 1.12 [1.05 to 1.20]), and stroke (HR, 95% CI: 1.19 [1.07 to 1.32]) after adjustment for CVD risk factors and potential confounders. There was no evidence of interaction with sex or ethnicity. Conclusion The QT interval is associated with incident cardiovascular events in middle-aged and older adults without prior cardiovascular disease.

Relationship Between QT Interval and Outcome in Low‐Flow Low‐Gradient Aortic Stenosis With Low Left Ventricular Ejection Fraction

“…Yet, the underlying mechanisms related to the higher mortality observed in patients with prolonged QT interval remain unclear. In this study by Beinart et al that included a cohort of middle‐aged participants free of cardiovascular diseases (CVD) at baseline, the authors suggested that LV abnormalities such as LV hypertrophy, which has been shown to be positively associated with high sympathetic tone and longer QT interval, may explain, at least in part, this association 12. In our study, there was no significant association between LV mass measured by echocardiography and QT c .…”

Electrocardiographic Impact of Myocardial Diffuse Fibrosis and Scar: MESA (Multi-Ethnic Study of Atherosclerosis)

“…Recently, Scott et al (35) reported a strong association between the presence of subendocardial LV scar and prolonged QT in patients with coronary heart disease. In addition, we found that the relationship between LV scar and QT is independent of LV structure indexes, despite the QT interval having a positive association with LV mass (20). The QT interval varies as a function of sympathetic and parasympathetic tone.…”

“…To calculate QTc from the uncorrected QT and heart rate, we followed the recommendations of the American Heart Association, the American College of Cardiology, and the Heart Rhythm Society for the standardization and interpretation of ECG studies (19). In this context, QTc was QT calculated by using a linear regression method to adjust for covariates (age, ethnicity, sex, and RR interval of the present study participants) with model residuals (20,21). We also assessed other traditional heart rate-QTcs using the Framingham formula, the Bazett formula, the Hodge formula, and the Fridericia formula.…”

Electrical Instability of Myocardium in Infarction Patients and Its Prognostic Significance

“…Важным предиктором является сниже-ние SDNN <100 мс, которое свидетельствует о сни-жении ВРС за счет повышения тонуса симпатиче-ской нервной системы, что позволяет прогнозиро-вать такие важные осложнения как ранняя постинфарктная стенокардия и левожелудочковая недостаточность. Существует мнение, что интервал QT также является показателем симпатического тонуса [9]. На основании полученных данных разра-ботана таблица вероятных предикторов прогнозиро-вания в первые два дня заболевания дальнейшего течения госпитального этапа с указанием конкрет-ных осложнений, что очень важно для адекватного лечения каждого пациента.…”