ECG criteria for accurate localization of left anterolateral and posterolateral accessory pathways

Noninvasive localization of cardiac arrhythmias using electromechanical wave imaging

Cardiac arrhythmias are a major cause of morbidity and mortality worldwide. The 12-lead electrocardiogram (ECG) is the current noninvasive clinical tool used to diagnose and localize cardiac arrhythmias. However, it has limited accuracy and is subject to operator bias. Here, we present electromechanical wave imaging (EWI), a high-frame rate ultrasound technique that can noninvasively map with high accuracy the electromechanical activation of atrial and ventricular arrhythmias in adult patients. This study evaluates the accuracy of EWI for localization of various arrhythmias in all four chambers of the heart before catheter ablation. Fifty-five patients with an accessory pathway (AP) with Wolff-Parkinson-White (WPW) syndrome, premature ventricular complexes (PVCs), atrial tachycardia (AT), or atrial flutter (AFL) underwent transthoracic EWI and 12-lead ECG. Three-dimensional (3D) rendered EWI isochrones and 12-lead ECG predictions by six electrophysiologists were applied to a standardized segmented cardiac model and subsequently compared to the region of successful ablation on 3D electroanatomical maps generated by invasive catheter mapping. There was significant interobserver variability among 12-lead ECG reads by expert electrophysiologists. EWI correctly predicted 96% of arrhythmia locations as compared with 71% for 12-lead ECG analyses [unadjusted for arrhythmia type: odds ratio (OR), 11.8; 95% confidence interval (CI), 2.2 to 63.2; P = 0.004; adjusted for arrhythmia type: OR, 12.1; 95% CI, 2.3 to 63.2; P = 0.003]. This double-blinded clinical study demonstrates that EWI can localize atrial and ventricular arrhythmias including WPW, PVC, AT, and AFL. EWI when used with ECG may allow for improved treatment for patients with arrhythmias.

Delta wave notching time is associated with accessory pathway localization in patients with Wolff-Parkinson-White syndrome

PURPOSE

Our aim was to investigate the relation between delta wave notching time (DwNt) and accessory pathway location in patients with Wolff-Parkinson-White (WPW) syndrome.

METHODS

The retrospective study included 149 WPW patients who underwent ablation therapy. DwNt was defined as the duration between the initial point of QRS and the notching in the delta wave. DwNt was divided by QRS duration to obtain the delta wave index (Dwi).

RESULTS

Patients with left-sided accessory pathway (AP) had significantly higher DwNt (p < 0.001) and Dwi (p = 0.027) values. The R wave voltage in lead I (p = 0.037) and S wave voltage in lead V1 (p = 0.005) values were significantly higher in patients with right-sided AP compared to patients with left-sided AP. When 27 ms was taken as the DwNt cut-off value, higher durations determined the left-sided AP location with a sensitivity of 91% and a negative predictive value of 91.4%. Dwi cutoff values ≥ 0.29 were accepted to indicate a left-sided AP location with a sensitivity of 91.2% and a NPV of 91.4%.

CONCLUSIONS

WPW patients with left-sided AP have longer DwNt values than patients with right-sided AP.