Abstract 3244: Echocardiographically-guided Optimization of LVOT VTI Improves Parameters of Dyssynchrony Following Cardiac Resynchronization Therapy in Heart Failure
Cardiac resynchronization therapy (CRT) is a recognised treatment option for a select group of patients with heart failure, i.e. those with New York Heart Association (NYHA) class III-IV symptoms, left ventricular ejection fraction ≤35% and either a QRS ≥150ms or a QRS 120 –149ms with echocardiographic evidence of mechanical dyssynchrony. Despite these selection criteria to identify those patients most likely to benefit from device implantation ~30% do not obtain significant clinical benefit from therapy. AV and VV optimization of cardiac output, as assessed by LVOT VTI may improve parameters of mechanical dyssynchrony on echocardiography, which may translate to clinical improvement and response to therapy in this group of patients.
Methods: We studied the acute effect of echocardiographic optimization on LVOT VTI in a group of 16 patients (age 71.5±8.4, 69% male) with symptomatic heart failure (NYHA class 3.5±0.5; NT-proBNP 2570.4±421.2 ng/L [Normal range <222 ng/L]) who had not obtained significant clinical response following CRT. Echocardiographic parameters of dyssynchrony were recorded pre- and immediately post-optimization. Tissue Doppler of the basal, septal, lateral and anterior walls were also recorded with time from QRS onset to maximal systolic velocity calculated. Results are expressed as mean ± standard deviation.
Results: AV and VV optimization resulted in significant improvement in LVOT VTI from 76.3±12.1 cm/s pre-optimization to 114.3±13.4 cm/s immediately post-optimization (p<0.005). Interventricular dyssynchrony improved significantly: aortic pre-ejection time reduced from 140.8±17.6 ms to 126.5±26.4 ms (p=0.05) and interventricular mechanical delay reduced from 46.6±10.2 ms to 12.0±6.8 ms (p<0.005). Intraventricular dyssynchrony also improved significantly: septal to posterior wall delay reduced from 159.7±88.1 ms to 94.6±84.3 ms (p<0.05). Tissue doppler of the septal and lateral walls showed significant reduction in opposing wall delay from 96.0±56.5 ms to 55.3±42.7 ms (p=0.03).
Conclusion: Optimization of LVOT VTI by echocardiography in CRT non-responders results in significant immediate improvement in the parameters of both inter- and intraventricular dyssynchrony.