Electrocardiographic QRS voltage amplitude improvement by intramyocardial radiofrequency ablation in patients with hypertrophic obstructive cardiomyopathy and one year follow up

Abstract

Objectives: This study aimed to determine whether the serial changes of the electrocardiogram is associated with regression of left ventricular hypertrophy (LVH) after Liwen procedure.

Background: Clinical application of the echocardiography-guided percutaneous intramyocardial septal radiofrequency ablation (PIMSRA, Liwen procedure) is an innovative approach to treat hypertrophic obstructive cardiomyopathy (HOCM).

Methods: We enrolled 30 consecutive patients with HOCM who had undergone Liwen procedure in our Hypertrophic Cardiomyopathy Center, from June 2016 to January 2018. Electrocardiography (ECG) and echocardiogram were performed before and after Liwen procedure, and at each follow-up (1-week, 1, 3, 6 months and 1 year). The Sokolow-Lyon index (SLi), Q wave, R wave, S wave amplitude of 12-lead ECG and interventricular septal (IVS) thickness, left ventricular mass index (LVMI) by echocardiograms were measured in each patient. The sum of the ECG QRS amplitude on each lead was calculated. The reduction of SLi and QRS amplitude were used as improvement index.

Results: The ECG leads with most improvement rate of the QRS wave amplitude of all cases were V1 and V2, both at 90%. The QRS wave amplitude in V1 leads and SLi were positively correlated with IVS thickness and LVMI at baseline and 1 year after Liwen procedure, respectively. The reduction of IVS thickness, LVMI and QRS wave amplitude in leads V1 and V2 were significant at one month after ablation and the follow-up period. SLi was significantly decreased at 3 months during the observation period. Similarly, the improvement of ECG QRS wave amplitude after the Liwen procedure tracked the gradual thinning of the IVS and the changes of SLi reflected the regression of LVH.

Conclusion: The QRS wave amplitude reductions in lead V1 and SLi may be good indicators for evaluating the postoperative interventricular septal remodeling of the Liwen procedure.

Keywords: ECG QRS wave amplitude; Hypertrophic obstructive cardiomyopathy; Interventricular septal thickness; Liwen procedure; Percutaneous intramyocardial septal radiofrequency ablation.