J Korean Med Sci.  2023 Jun;38(24):e186. 10.3346/jkms.2023.38.e186.

Predictive Value of Electromechanical Window for Risk of Fatal Ventricular Arrhythmia

• Rhee TM
• Ahn HJ
• Kim S
• Lee SR
• Choi EK
• Oh S

• KMID: 2543975
• DOI: http://doi.org/10.3346/jkms.2023.38.e186

Abstract

Background
As an indicator of electro-mechanical coupling, electromechanical window (EMW) can be used to predict fatal ventricular arrhythmias. We investigated the additive effect of EMW on the prediction of fatal ventricular arrhythmias in high-risk patients.
Methods
We included patients who had implantable cardioverter-defibrillator (ICD) implanted for primary or secondary prevention. The event group was defined as those who received an appropriate ICD therapy. We acquired echocardiograms at ICD implantation and follow-up. The EMW was calculated as the difference between the interval from QRS onset to aortic valve closure and QT interval from the electrocardiogram embedded in the continuous wave doppler image. We evaluated the predictive value of EMW for predicting fatal ventricular arrhythmia.
Results
Of 245 patients (67.2 ± 12.8 years, 63.7% men), the event group was 20.0%. EMW at baseline (EMW-Baseline) and follow-up (EMW-FU) was significantly different between event and control groups. After adjustment, both EMW-Baseline (odds ratio [OR]_adjust 1.02 [1.01– 1.03], P = 0.004) and EMW-FU (OR_adjust 1.06 [1.04–1.07], P < 0.001) remained as significant predictors for fatal arrhythmic events. Adding EMW-Baseline significantly improved the discriminating ability of the multivariable model including clinical variables (area under the curve [AUC] 0.77 [0.70–0.84] vs. AUC 0.72 [0.64–0.80], P = 0.004), while a univariable model using EMW-FU alone showed the best performance among models (AUC 0.87 [0.81– 0.94], P = 0.060 against model with clinical variables; P = 0.030 against model with clinical variables and EMW-Baseline).
Conclusion
The EMW could effectively predict severe ventricular arrhythmia in ICD implanted patients. This finding supports the importance of incorporating the electro-mechanical coupling index into the clinical practice for predicting future fatal arrhythmia events.

Keyword

Electromechanical Window; Ventricular Arrhythmia; Sudden Cardiac Death; Echocardiography; Implantable Cardioverter-Defibrillator

Figure

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  Fig. 1 Representative cases with measurements of EMW. Representative figures of measuring EMW in (A) case with fatal arrhythmic event and (B) case without fatal arrhythmic event are presented.QAoC = time interval between the onset of QRS complex and aortic valve closure, EMW = electromechanical window, ms = millisecond.

• 

  Fig. 2 Violin plot of EMW at baseline and follow-up according to the occurrence of fatal arrhythmic event. Violin plots presenting distribution of (A) EMW at baseline, and (B) EMW at follow-up according to the occurrence of fatal arrhythmic event are shown.EMW = electromechanical window, ms = millisecond.

• 

  Fig. 3 Scatter plot presenting correlation between QTc and EMW according to the occurrence of fatal arrhythmic event. Scatter plots of QTc and EMW (A) at baseline and (B) at follow-up are presented.EMW = electromechanical window, QTc = corrected QT interval, ms = millisecond.

• 

  Fig. 4 Comparison of models including EMW versus clinical variables for predicting fatal arrhythmic event. ROC curves of predictive models for fatal arrhythmic event are shown.EMW = electromechanical window, FU = follow-up, AUC = area under the curve, ROC = receiver operation characteristic, CI = confidence interval.aIncluded secondary prevention, hypertrophic cardiomyopathy, primary electrical disorder, use of class III AED at baseline, left ventricular ejection fraction, and atrial fibrillation/atrial flutter at baseline.

• 

  Fig. 5 Best cutoff value of EMW. The adjusted probability with 95% CI of event and the density plot of EMW-FU are presented. The best cutoff value of EMW-FU was calculated from the multivariable logistic regression model using the method by Liu et al.CI = confidence interval, EMW = electromechanical window, FU = follow-up, ms = millisecond.

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