Evaluation of left ventricular longitudinal function and synchrony after dual chamber pacemaker implantation.

BACKGROUND AND OBJECTIVE: To evaluate left ventricular (LV) longitudinal function and dyssynchrony mechanisms after dual chamber pacemaker implantation. MATERIALS AND METHODS: The speckle tracking imaging technique was used for quantification of global longitudinal function of the left ventricle and for dyssynchrony evaluation before pacemaker implantation and after 3-month follow-up. The study group consisted of 98 patients with conventional indications for dual chamber pacemaker implantation. RESULTS: Speckle tracking echocardiographic methods and image postprocessing revealed impairment of global longitudinal strain and significant LV dyssynchrony derived from 12 basal and mid-septum segments usually untraceable with conventional echocardiographic methods. Despite good physical performance and ejection fraction, global longitudinal strain significantly decreased in all patients from -15.08±0.46 to -13.56±0.5 (P<0.05) as well as mitral annulus movement decreased from 11.57±2.41 to 8.46±1.74cm/s (P<0.001) and from 12.55±2.75 to 10.78±2.82mm (P<0.001). It was expected that patients with dual chamber pacemaker will develop inter- and intraventricular dyssynchrony, but our study showed that pacing lead position did not prevent from LV dysynchronisation and only changed the mechanism. CONCLUSIONS: Global longitudinal strain and LV dyssynchrony assessment enables us to detect early signs of LV dysfunction. Mechanisms of dyssynchrony development will be useful for pacemaker programing choices in order to prevent further dyssynchronisation.

Predictors of positive response to cardiac resynchronization therapy.

BACKGROUND: Approximately 30% of patients treated with cardiac resynchronization therapy (CRT) do not achieve favourable response. The purpose of the present study was to identify echocardiographic and clinical predictors of a positive response to CRT. METHODS: The study included 82 consecutive heart failure (HF) patients in New York Heart Association (NYHA) functional class III or IV with left bundle branch block (LBBB), QRS duration ≥ 120 ms and left ventricular ejection fraction (LVEF) ≤ 35%. Statistical analysis was performed using IBM SPSS statistical software (SPSS v.21.0 for Mac OS X). A p value < 0.05 was considered statistically significant. RESULTS: Echocardiographic response was established in 81.6% and clinical response was achieved in 82.9% of patients. Significant univariate predictors of favourable echocardiographic response after 12 months were smaller left ventricular end-diastolic diameter (LVEDD) (odds ratio [OR] 0.89; 95% confidence interval [CI] 0.82 - 0.97, p = 0.01), and smaller left ventricular end-systolic diameter (LVESD) (OR 0.91; 95% CI 0.85 - 0.98, p = 0.01). Lower uric acid concentration was associated with better echocardiographic response (OR 0.99; 95% CI 0.99 - 1.0, p = 0.01). Non-ischemic HF etiology (OR 4.89; 95% CI 1.39 - 17.15, p = 0.01) independently predicted positive clinical response. Multiple stepwise regression analysis demonstrated that LVEDD lower than 75 mm (OR 5.60; 95% confidence interval [CI] 1.36 - 18.61, p = 0.01) was the strongest independent predictor of favourable echocardiographic response. CONCLUSIONS: Smaller left ventricular end-diastolic and end-systolic diameters and lower serum uric acid concentration were associated with better response to CRT. Left ventricular end-diastolic diameter and non-ischemic heart failure etiology were the strongest independent predictors of positive response to CRT.