| Background and ObjectivesHeart Failure (HF) is one of the important factors which influencing national health. Cardiac Resynchronization Therapy (CRT) can improve the symptoms and mortality of HF patients with cardiac dyssynchrony. However, non-responder proportion with CRT therapy is about 30%. It has been a hot topic to investigate predictors of CRT response. The present study showed outcomes of the CRT recipients in our center, clarifying the correlation between Velocity Vector Imaging (ⅤⅥ) and CRT responder. And investigate the relationship between ECG and CRT response at the same time.MethodsPart One:Investigate the CRT recipients in our center between 2001 and 2014 respectively. According to left ventricular ejection fraction (LVEF) and reverse remodeling, CRT recipients were divided into three groups:non-responder, responder and super-responder groups. The clinical and device parameters were analyzed. The HF symptoms and prognosis were also compared among groups.Part Two:This part consisted of 48 patients with medically refractory, moderate to severe HF. Before CRT implantation, all patients received VVI to analyze left ventricular long axis dyssynchrony including time to peak of systolic velocity (Ts max-min), standard deviation of the time to peak of systolic velocity (Ts-SD). During follow up, the patients were examined cardiac echocardiograph. Responder was defined as 15% decrease in left ventricular end-systolic volume (LVESV) at 6-month follow-up. ROC curve was drew and the area under the curve (AUC) was calculated the predictive value of each index.Part Three:This part analyzed ECG of 92 CRT patients who were followed up in our center. The definition of responder is LVESV reduction≥15% within 6 months after CRT. QRS width and axis variation were analyzed. After CRT therapy, the ventricular activation was changed as leftâ†'right, posteriorâ†'anterior and axis changed in a clockwise direction (frontal plane). The change in more than two directions was defined as prominent axis change. The aim of the study was to investigate the role of ECG in predicting CRT response.ResultsPart One:Ninty-two patients were followed up. The number of non-responder, responder and super-responder groups were 28 (30.9%),64 (69.1%) and 27 (29.4%) respectively. No obvious differences were observed at age, gender, medical therapy among groups. The number of atrial fibrillation patients were much higher in non-responder group than in responder, super-responder group (P=0.004). After CRT therapy, LVEF (Left Ventricular Ejection Fraction), LVEDD (Left Ventricular End Diastolic Diameter),6MWD (6-Minute Walking Distance), LVESV and NYHA grade were improved greatly than before CRT in responder and super-responder groups (P<0.01). However, the above parameters deteriorated in non-responder group except NYHA grade.Part Two:Thirty patients were defined as responder. When using Ts max-min to predict response, the AUC of ROC curves was 0.76 ± 0.07. The sensitivity and specifity was 70.8% and 77.8% respectively when Ts max-min≥124.0 ms. When using Ts-SD to predict response, the AUC of ROC curves was 0.82 ± 0.07. The sensitivity and specifity was 79.2% and 71.2% respectively when Ts-SD≥ 40.5.Part Three:Sixty-four patients were defined as responder. The proportion of female, LBBB was much higher in responder group than in non-responder group (28.1% and 89.1% versus 14.3% and 71.4%, P<0.05). In multivariate regression analysis, QRS width>140ms and prominent axis change were found to be independent predictors of CRT responders. An increase of 1 unit in axis was associated with roughly a fivefold increase in CRT response (OR 5.12,95% CI 1.67 to 15.51, p= 0.004). AF was associated with decrease in CRT response (OR 0.25,95% CI0.08 to 0.80, p= 0.02).Conclusions1. CRT reduce symptoms, morbidity and mortality among heart failure patients with cardiac dyssynchrony2. The proportion of HF patients with CRT receiving guideline indicated medical therapy is reasonable3. Atrial fibrillation may lead to inappropriate shock, insufficient pacing after CRT4. Ts-SD may play a role in predicting CRT response5. QRS width> 140ms and prominent axis change anticipate higher ability of CRT response... |
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