Background: Supraventricular tachycardia (SVT) is most commonly caused by atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular tachycardia (AVRT). Electrocardiograms (ECG) have been helpful in identifying SVT but there have been limited studies and algorithms that have been able to accurately predict AVNRT from AVRT. This study aims to compare the accuracy of the presence of the aVL notch versus the presence of pseudo-R' and pseudo-S in diagnosing AVNRT.
Method: This is a cross-sectional study utilizing consecutive patients who underwent electrophysiologic studies (EPS) or radiofrequency ablation (RFA) for supraventricular tachycardia (SVT) from the Philippine Heart Center from January 2006 to December 2011. ECG tracings of 78 patients were analyzed by two electrophysiologists who were blinded to the result of the EPS/ RFA.
Results: Results show that the presence of the aVL notch showed statistically significant sensitivity and specificity of 44.0 and 92.1 %, respectively. If the aVL notch is used in combination with the presence of pseudo- R', there is also statistically significant sensitivity and specificity of 60.0 and 71.1 %, respectively. However if all three ECG criteria are present (aVL notch, pseudo-S and pseudo-R') the sensitivity and specificity were 28.0% and 100.0%.
Conclusion: The presence of the aVL notch can be utilized as a diagnostic criterion to differentiate between AVNRT and AVRT. The sensitivity to diagnose AVNRT can be increased if the aVL notch and pseudo-R' are both present. It is recommended that the findings in this study be validated using a larger population.