Evaluation of the Tp-Te Interval, QTc and P-Wave Dispersion in Patients With Coronary Artery Ectasia
Ronan Conlon1, Richard Tanner1, Santhosh David1
1Letterkenny University Hospital, Letterkenny, Co. Donegal, Ireland.
Insights
Coronary artery ectasia (CAE) is linked to increased risks of arrhythmias, as indicated by prolonged electrocardiographic markers like Tp-Te and QTc dispersions. This study suggests CAE may have a pro-arrhythmogenic nature.
Area of Science:
- Cardiology
- Electrocardiography
- Cardiac Electrophysiology
Background:
- Coronary artery ectasia (CAE) involves diffuse dilatation of coronary arteries, with increasing prevalence.
- Electrocardiographic markers such as Tp-Te interval, P-wave, and QTc dispersions are emerging indicators of arrhythmia risk.
- Limited data exists on the arrhythmogenic potential of CAE.
Purpose of the Study:
- To investigate the association between coronary artery ectasia (CAE) and specific electrocardiographic parameters.
- To evaluate Tp-Te interval, Tp-Te/QT ratio, QTc dispersion, and P-wave dispersion in patients with CAE.
- To explore the potential pro-arrhythmogenic nature of CAE.
Main Methods:
- A retrospective comparative study included 20 patients with isolated CAE and 20 matched controls.
- Patients presented with chest pain and underwent coronary angiography.
- Electrocardiogram (ECG) parameters including Tp-Te interval, Tp-Te/QT ratio, QTc dispersion, and P-wave dispersion were measured and analyzed.
Main Results:
- Patients with CAE exhibited significantly prolonged mean Tp-Te intervals (95.5 ± 9.01 ms) and Tp-Te/QT ratios (0.22 ± 0.02) compared to controls.
- Significantly increased QTc dispersion (31.2 ± 3.71 ms) and P-wave dispersion (31.9 ± 5.46 ms) were observed in the CAE group.
- No significant difference in ventricular activation time (VAT) was found between the groups.
Conclusions:
- Electrocardiograms of patients with CAE show significant increases in Tp-Te, Tp-Te/QT ratio, QTc intervals, and P-wave dispersions.
- These findings suggest that coronary artery ectasia may possess a pro-arrhythmogenic characteristic.
- Further research is warranted to elucidate the arrhythmogenic mechanisms in CAE.
Background:
Coronary artery ectasia (CAE) is defined as a diffuse dilatation of the diameter of the ectatic segment of the coronary artery, 1.5 times greater than that of the adjacent segment. The Tp-Te interval, P-wave and QTc dispersions are relatively new electrocardiographic markers associated with an increased risk of developing arrhythmias. Despite CAE increasing in prevalence in recent years, there is a sparsity of data available about its arrhythmogenic effect. The aim of the study was to evaluate QTc, P-wave dispersion and Tp-Te and Tp-Te/QT ratio in patients with CAE.
Methods:
A retrospective comparative study was designed for consecutive age- and sex-matched patients. Twenty patients with isolated CAE (group 1) and 20 control subjects (group 2), with normal coronary arteries, were included. All patients presented with chest pain and coronary angiogram was indicated. Outcome measures included Tp-Te interval, Tp-Te/QT ratio, QTc dispersion and P-wave dispersion. Measurement of electrocardiogram (ECG) parameters was conducted using standardized digital online software. Descriptive and inferential statistics were performed.
Results:
Mean Tp-Te (95.5 ± 9.01 ms) and Tp-Te/QT ratio (0.22 ± 0.02) were significantly prolonged in CAE group (Tp-Te: 84 ± 5.62 ms, P = 0.00009; Tp-Te/QT ratio: 0.20 ± 0.01, P = 0.00004). In addition, QTc (31.2 ± 3.71 ms) and P-wave dispersion (31.9 ± 5.46 ms) were significantly increased in comparison to the control group (QTc: 27.6 ± 2.82 ms, P = 0.00532 and 20 ± 3.77 ms, P = 0.00003 respectively). However, there was no difference in ventricular activation time (VAT) between groups.
Conclusions:
CAE ECGs were found to be associated with increased Tp-Te, Tp-Te/QT ratio, QTc intervals and P-wave dispersions. This may suggest that CAE existence has a pro-arrhythmogenic nature.
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However, the point estimate is most likely not the exact value of the population parameter, but close to it. After calculating point estimates, we construct interval estimates, called confidence intervals or prediction intervals. This prediction interval comprises a range of values unlike the point estimate and is a better predictor of the observed sample value, y.