Negativity of the electromechanical window: relation to frequent premature ventricular complexes

OBJECTIVE

The electromechanical window (EMW) was investigated as a new predictor of arrhythmia in the presence of long QT. However, the use of EMW to predict idiopathic frequent ventricular premature complexes (PVCs) in those with normal QT intervals has not been clarified.

PATIENTS AND METHODS

This single-center study included consecutive patients who presented to the Cardiology Clinic with palpitations and were found to have idiopathic PVC on 24-hour Holter monitoring. Those with a PVC/24-hour frequency of < 1% were defined as group 1, 1-10% as group 2, and > 10% as group 3. The EMW was defined as the time difference (in ms) between the aortic valve closure and the end of the QT interval, measured from an ECG on the concurrent echocardiogram.

RESULTS

A total of 148 patients were included in the study, 64% (n = 94) of which were female. The patients' mean age was 50.11 ± 14.7. The groups were similar in terms of the patients' age, BMI, and comorbidities. There was a statistically significant difference between the three groups in terms of the EMW measurements (group 1: 3.78 ± 19.6, group 2: -7 ± 30.9, group 3: -34.83 ± 55.2 ms: p < 0.001). In the multivariate regression analysis, the EMW (OR 0.971, p = 0.007) and every 10-ms decrease in the EMW (OR 1.254, p = 0.011) were thus determined to be independent predictors of PVC > 10%. An EMW value of ≤ -15 ms was associated with the frequency of 24-h PVC > 10%, with a sensitivity of 70% and a specificity of 70% (AUC 0.716, 95% CI: 0.636-0.787 p < 0.001).

CONCLUSIONS

The results showed that a negative increase in the EMW may be associated with frequent idiopathic PVCs.

The relationship between T-wave peak-to end interval and ST segment recovery on intracoronary ECG during primary PCI

OBJECTIVE

T-wave peak to end interval (TPE) is a measure of repolarization dispersion, which has been reported as a major arrhythmogenic factor post acute myocardial infarction. The aim of our study was to investigate the changes in TPE in this patient population with regard to peri-procedural intracoronary ECG findings.

PATIENTS AND METHODS

Forty-four patients (34 male and mean age of 54.9 ± 10.9 years) with acute STEMI were included. Intracoronary ECG was performed during primary PCI. TPE indices were calculated before and after the procedure. Measurement of the intracoronary ST-segment was carried out before and just after coronary blood flow was established in the infarct related artery. Intracoronary ST-segment resolution (IC-STR) was defined as ≥ 1 mm compared to baseline.

RESULTS

There was no difference with respect to baseline characteristics when patients with IC-STR were compared with patients without IC-STR. TPE values decreased significantly after primary PCI in patients with IC-STR (80.9 ± 22.8 ms vs. 65.8 ± 14.4 ms; p < 0.001) whereas they did not change significantly after PCI in patients without IC-STR (79.2 ± 20.9 ms vs. 68.5 ± 16.3 ms; p = 0.18).

CONCLUSIONS

TPE measured from surface ECG recordings is significantly reduced in STEMI patients with successful reperfusion after primary PCI, as determined by IC-ECG recordings.