Coupling interval variability differentiates ventricular ectopic complexes arising in the aortic sinus of valsalva and great cardiac vein from other sources: mechanistic and arrhythmic risk implications

Abstract

Objectives: The objective of this study was to determine whether premature ventricular contractions (PVCs) arising from the aortic sinuses of Valsalva (SOV) and great cardiac vein (GCV) have coupling interval (CI) characteristics that differentiate them from other ectopic foci.

Background: PVCs occur at relatively fixed CI from the preceding normal QRS complex in most patients. However, we observed patients with PVCs originating in unusual areas (SOV and GCV) in whom the PVC CI was highly variable. We hypothesized that PVCs from these areas occur seemingly randomly because of the lack of electrotonic effects of the surrounding myocardium.

Methods: Seventy-three consecutive patients referred for PVC ablation were assessed. Twelve consecutive PVC CIs were recorded. The ΔCI (maximum - minimum CI) was measured.

Results: We studied 73 patients (age 50 ± 16 years, 47% male). The PVC origin was right ventricular (RV) in 29 (40%), left ventricular (LV) in 17 (23%), SOV in 21 (29%), and GCV in 6 (8%). There was a significant difference between the mean ΔCI of RV/LV PVCs compared with SOV/GCV PVCs (33 ± 15 ms vs. 116 ± 52 ms, p < 0.0001). A ΔCI of >60 ms demonstrated a sensitivity of 89%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 94%. Cardiac events were more common in the SOV/GCV group versus the RV/LV group (7 of 27 [26%] vs. 2 of 46 [4%], p < 0.02).

Conclusions: ΔCI is more pronounced in PVCs originating from the SOV or GCV. A ΔCI of 60 ms helps discriminate the origin of PVCs before diagnostic electrophysiological study and may be associated with increased frequency of cardiac events.

Keywords: aortic sinus of Valsalva; coupling interval; great cardiac vein; premature ventricular contraction.

Figure 1. Scatter Plot of ΔCI Demonstrating Variable CI in PVCs Originating From the SOV/GCV But Not in PVCs From the RV/LV

The scatter plot demonstrates that PVCs originating from the SOV/GCV predominantly have a ΔCI <60 ms, whereas RV/LV origin PVCs consistently have a ΔCI >60 ms with a ΔCI of <60 ms, demonstrating a sensitivity of 89%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 94%. ΔCI = (maximum – minimum) coupling interval; PVC = premature ventricular complexes; RV/LV = right ventricle/left ventricle; SOV/GCV = sinus of Valsalva/great cardiac vein.

Figure 2. ROC Curve

ROC curve plotting the true positive rate (sensitivity) versus false positive rate (1 – specificity) documenting the ability of ΔCI to differentiate SOV/GCV and RV/ LV origin PVCs with an AUC = 0.946. The ROC curve in combination with Youden’s index supports a ΔCI of <60 ms. A <60-ms cutoff demonstrates a sensitivity of 89%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 94%. AUC = area under the curve; ROC = receiver-operating characteristic; other abbreviations as in Figure 1.

Figure 3. 12-Lead ECGs Demonstrating Examples of PVCs With Variable and Fixed Coupling

An example of (A) variable CI seen in a SOV/GCV source; and (B) stable CI of an RVOT source are shown. ECG = electrocardiogram; RVOT = right ventricular outflow tract; other abbreviations as in Figure 1.

Figure 4. 12-Lead ECGs Demonstrating Examples of PVCs With Variable and Fixed Coupling Related to Unsuccessful Ablation

An example of an ECG of a PVC in a patient that shows (A) stable coupling before ablation; and (B) variable coupling after initial failed ablation attempt. Abbreviations as in Figures 1 and 3.