High-frame-rate speckle-tracking echocardiography successfully mapped left ventricular activation, detecting significant septal-to-lateral dyssynchrony during BiV off (36±2ms vs 81±21ms, p<0.01).
Observational (n=45)
Can high-frame-rate speckle-tracking echocardiography accurately map left ventricular mechanical activation sequences in healthy volunteers and patients with LBBB?
High-frame-rate speckle-tracking echocardiography is a promising non-invasive tool for mapping left ventricular mechanical activation and assessing dyssynchrony in patients with LBBB.
p-value: p=<0.01
Abstract Objective Electrical activation mapping is essential for identifying ablation targets in the treatment of cardiac arrhythmias. This study investigates high-frame-rate (HFR) speckle-tracking echocardiography (STE) as a non-invasive alternative to conventional electrophysiologic studies for constructing mechanical activation maps and defining left ventricular (LV) activation onset. Methods 20 healthy volunteers (HV) and 25 patients with a biventricular pacemaker (BiV) underwent HFR ultrasound scanning. Patients were scanned during BiV on and off, hence reintroducing native activation - left bundle branch block (LBBB) pattern. 5 patients were additionally scanned after changing the LV lead pacing pole. A custom-made 2D-HFR-STE algorithm tracked the cardiac wall in the 3 conventional apical echocardiographic views. Strain rate (SR) curves were computed for each wall segment in a 16-segment LV model to measure the time between electrical and mechanical activation (i.e. time between QRS onset and first positive-to-negative zero-crossing in the SR curve). The timings were displayed in a bull’s-eye plot, representing each subject’s activation map. Results For most HV, activation started from mid-anteroseptum, at 23±5ms, spreading basal-inferolaterally at 50±8ms. During BiV off, the average septal activation was 36±2ms; the average lateral was 81±21ms (p0.01). During BiV on, the respective times were 53±6ms and 52±6ms (p=0.3). Altering the LV lead pacing pole changed the lateral wall activation onset accordingly. Conclusions HFR-STE was able to map normal activation, measure the known septal-to-lateral LBBB dyssynchrony and identify the paced segment in 92% of the cases. HFR-STE could be a promising tool in constructing LV activation maps.
Papangelopoulou et al. (Wed,) conducted a observational in Left bundle branch block (n=45). High-frame-rate speckle-tracking echocardiography (HFR-STE) vs. BiV on vs BiV off was evaluated on Time between electrical and mechanical activation (QRS onset to first zero-crossing in SR curve) (p=<0.01). High-frame-rate speckle-tracking echocardiography successfully mapped left ventricular activation, detecting significant septal-to-lateral dyssynchrony during BiV off (36±2ms vs 81±21ms, p<0.01).