[Prognostic value of QTc interval dispersion changes during exercise testing in hypertensive men]
Insights
QTc dispersion increases during exercise in patients with left ventricular hypertrophy. However, this increase does not predict future cardiovascular events, unlike left ventricular mass index.
Area of Science:
- Cardiology
- Electrophysiology
- Exercise Physiology
Context:
- Left ventricular hypertrophy (LVH) is associated with increased cardiovascular risk.
- The prognostic value of QTc dispersion during exercise testing (ET) in LVH patients is not well-established.
Purpose:
- To investigate the changes in QTc interval dispersion (QTcd) during ET in patients with hypertensive LVH.
- To determine the prognostic significance of QTcd during ET for adverse cardiovascular events over a five-year follow-up.
Summary:
- QTc dispersion significantly increased during ET in the LVH group.
- A correlation was observed between ST segment depression and QTcd.
- Neither QTc interval nor QTcd during ET predicted adverse cardiovascular events; however, left ventricular mass index (LVMI) showed prognostic value.
Impact:
- This study suggests that while QTcd changes during ET in LVH patients, it lacks predictive power for cardiovascular events.
- LVMI emerges as a significant prognostic marker in this population.
- Further research with larger cohorts is needed to confirm these findings.
Introduction:
The prognostic significance of QTc dispersion changes during exercise testing (ET) in patients with left ventricular hypertrophy is not clear.
Objective:
The aim was to study the dynamics of QTc interval dispersion (QTcd) in patients (pts) with left ventricular hypertrophy (LVH) during the exercise testing and its prognostic significance.
Method:
In the study we included 55 men (aged 53 years) with hypertensive left ventricular hypertrophy and a negative ET (LVH group), 20 men (aged 58 years) with a positive ET and 20 healthy men (aged 55 years). There was no statistically significant difference in the left ventricular mass index (LVMI) between LVH group and ILVH group (160.9+/-14.9 g/m2 and 152.8+/-22.7 g/m2). The first ECG was done before the ET and the second one was done during the first minute of recovery, with calculation of QTc dispersion. The patients were followed during five years for new cardiovascular events.
Results:
During the ET, the QTcd significantly increased in LVH group (56.8+/-18.0 - 76.7+/-22.6 ms; p<0.001). A statistically significant correlation was found between the amount of ST segment depression at the end of ETand QTc dispersion at the beginning and at the end of ET (r=0.673 and r=0.698; p<0.01). The QTc dispersion was increased in 35 (63.6%) patients and decreased in 20 (36.4%) patients during the ET. Three patients (5.4%) in the first group had adverse cardiovascular events during the five-year follow-up. A multiple stepwise regression model was formed by including age, LVMI, QTc interval, QTc dispersion and change of QTc dispersion during the ET. There was no prognostic significance of QTc interval and QTc dispersion during five-year follow-up in regard to adverse cardiovascular events, but prognostic value was found for LVMI (coefficient beta=0.480; p<0.001).
Conclusion:
The increase of QTc interval dispersion is common in men with positive ET for myocardial ischemia and there is a correlation between QTc dispersion and amount of ST segment depression. The increase of QTc interval dispersion during negative ET in patients with left ventricular hypertrophy has no significant predictive value for adverse cardiovascular events, as shown in our five-year follow-up study, but it requires confirmation by investigation of larger groups of patients.
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