QTc interval and survival in 75-year-old men and women from the general population

• Aims: The study concerns the relationship of the corrected QT (QTc) interval to 6.4 years of survival and to measures of cardiac function, such as echocardiographic variables and plasma levels of brain natriuretic peptide (BNP), in 75-year-old people. Methods and results: QTc was measured in a 12-lead electrocardiogram (ECG) in 210 men and 223 women, comprising a randomly selected sample from the general population (70% participation rate). The Sicard 440/740 computer-analysis program, with Hodges' formula for heart rate-based QT correction, was used. The optimal cut-off point for predicting survival according to the receiver operating characteristic curve was found between 429 and 430 ms. Individuals with a QTc interval of ≥430 ms (n = 115) had decreased survival when compared with those with shorter QTc interval (n = 318); the relative risk was 2.4 (95% confidence interval 1.5-3.7). The predictive ability of QTc reflects an association between QTc and the following variables: BNP, left ventricular mass, and left ventricular ejection fraction (but not diastolic filling patterns). Both Hodges' and Bazett's formulae for heart rate correction of the QT interval were useful for predicting survival. The median QTc was 415 ms using Hodges' formula and 430 ms with Bazett's formula. The QRS component of QTc predicted survival better than the rest of the QTc interval and was approximately as useful as the QTc interval itself. Conclusion: The computer-derived QTc obtained from the ordinary 12-lead ECG identifies high-risk individuals among elderly people from the general population.

Nyckelord

BNP

ECG

Echocardiography

Heart rate

QT

Risk stratification

antidepressant agent

antilipemic agent

beta adrenergic receptor blocking agent

brain natriuretic peptide

calcium channel blocking agent

digitalis

dipeptidyl carboxypeptidase inhibitor

diuretic agent

aged

article

confidence interval

controlled study

correlation analysis

data analysis software

diagnostic kit

diastole

electrocardiogram

female

geriatric patient

heart arrhythmia

heart function test

heart left ventricle ejection fraction

heart left ventricle filling

heart left ventricle mass

high risk patient

human

intermethod comparison

major clinical study

male

mathematical model

patient selection

population research

prediction

priority journal

protein blood level

QT interval

receiver operating characteristic

risk assessment

survival time

Chi-Square Distribution

Electrocardiography

Humans

Lipids

Long QT Syndrome

Natriuretic Peptide

Brain

Risk Factors

ROC Curve

Statistics

Nonparametric

Survival Analysis

Sweden

Publikations- och innehållstyp

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