QT interval variations and mortality risk: Is there any relationship?

Abstract

Abnormal prolongation and shortening of the electrocardiographic QT interval duration, which occur in the hereditary forms of long and short QT syndromes, are associated with an increased risk of ventricular arrhythmias and sudden cardiac death. Even within the normal range, these altered durations are associated with an increased mortality risk in the general population. While extreme prolongation or reduction of the QT interval predisposes patients to malignant ventricular arrhythmias and sudden cardiac death, the precise dose-response relationship between the QT interval and cardiovascular disease mortality is still unknown. This paper describes the need for more standardized methods for measuring and reporting the QT interval and the need for more precise assessments of the risk associated with QT interval variation.

Holter monitoring parameters in assessment of cardiovascular risk in patients with hypertension and obesity

“…The most unfavorable values of the circadian index were determined in patients with hypertension and obesity of the 1st degree: 1,09 (1,0;1,17), which was significantly lower than in patients with normal body weight (1,19 (1,12;1,27), p = 0,03), overweight (1,16 (1,1;1,23), p = 0,04) and morbid obesity (1,15 (1,09;1,21), p = 0.03). It was found that all patients with obesity of the І degree had values of the heart rate below 1,2.…”

“…The extension of the QT interval is currently considered one of the proven predictors of sudden cardiac death [1,13]. The existence of a relationship between the extension of the QT interval and the frequency of fatal ventricular arrhythmias, in particular polymorphic ventricular tachycardia of the type "pirouettes" has been proven by a number of studies.…”

The Assessment of Ventricular Arrhythmia Indicators Based on Electrocardiography in Patients With Differentiated Thyroid Cancer Followed Up With Levothyroxine Suppression

“…Prolongation and shortening of QT interval have been associated with ventricular arrhythmias and sudden cardiac death. 9 The Tp-e interval indicates the distance between the peak and end points of the T wave, and the amplification of this has also been found to be associated with malignant ventricular arrhythmias. 10 The Tp-e/QT and Tp-e/ QTc ratios are considered as the electrocardiographic index of arrhythmogenesis and as predictors of ventricular arrhythmias.…”

Correlation of Prolonged Corrected QT Interval With Ventricular Arrhythmias and In-Hospital Mortality Among ST-Elevation Myocardial Infarction Patients: A Mystique or Lucidity?

“…QT interval is the time slice of ventricular excitation and recovery represented from the initiation of the QRS complex to the termination of T wave on the ECG. Furthermore, the variations in heart rate cause significant alterations in the length of the QT interval and as a result, it is adjusted using the Bazett formula (QT/√RR interval) and referred to as corrected QT (QTc) interval [6][7][8]. The standard QTc interval of below 450 milliseconds (ms) in males and 460 ms in females represents normal ventricular conduction [8].…”

“…Furthermore, the variations in heart rate cause significant alterations in the length of the QT interval and as a result, it is adjusted using the Bazett formula (QT/√RR interval) and referred to as corrected QT (QTc) interval [6][7][8]. The standard QTc interval of below 450 milliseconds (ms) in males and 460 ms in females represents normal ventricular conduction [8]. On the contrary, the prolonged QTc represents the extended period of liability to progress to life-threatening arrhythmias.…”