Abstract 2137: Speckle Tracking Radial Strain Reveals Left Ventricular Dyssynchrony in Patients with Permanent Right Ventricular Pacing
Introduction: Atrioventricular node ablation and subsequent permanent RV pacing is an established treatment option in patients with atrial fibrillation. However, permanent RV pacing may have detrimental effects on LV function, related to the induction of LV dyssynchrony.
Objective: To evaluate the effects of RV pacing on LV function and LV dyssynchrony, as assessed with speckle tracking radial strain.
Methods: A total of 52 patients (28 men, age 61 ± 12 years), treated with AV node ablation and permanent RV pacing, were studied. At baseline and after a minimum of 1 year RV pacing, functional class was assessed and an echocardiogram was obtained. Radial strain was calculated on LV short axis images with novel software that tracks frame-to-frame movement of ‘speckles’ within the myocardium. Peak radial strain was assessed for 6 standard segments, and LV dyssynchrony was defined as a time difference ≥130 ms between peak radial strain of the septal and posterolateral segments.
Results: At baseline, LV dyssynchrony was absent in all patients. In contrast, after a mean of 3.8 ± 1.9 years of permanent RV pacing, radial strain curves revealed LV dyssynchrony in 25 of the 52 patients (48%). Mean difference between the septal and posterolateral regions was 34 ± 31 ms in patients without LV dyssynchrony, and 201 ± 62 ms in patients with LV dyssynchrony (p<0.05). In the patients with LV dyssynchrony, LV ejection fraction had decreased significantly, and LV volumes had increased significantly (Table 1⇓). In addition, NYHA functional class deteriorated in patients with LV dyssynchrony (from 1.8 ± 0.6 to 2.3 ± 0.7, p<0.05), whereas it improved in patients without LV dyssynchrony (from 1.7 ± 0.6 to 1.4 ± 0.6, p<0.05).
Conclusions: Speckle tracking radial strain reveals that 48% of the patients develop LV dyssynchrony after permanent RV pacing. LV dyssynchrony was associated with a decrease in LV systolic function and functional class. These patients may benefit from biventricular pacing.