Abstract
A number of trials have demonstrated the effect of cardiac resynchronization therapy (CRT) on functional improvement and reversed left ventricle remodeling. Meeting contemporary guidelines approximately 30- 40% of patients do not respond to CRT (non-responders). To quantify the predictive ability of basal QRS width and basal echocardiographic parameters of left ventricle contraction dyssynchrony in our group of CRT patients. To compare effectiveness of these parameters assessment in patients with ischemic (iCMP) and non-ischemic cardiomyopathy (niCMP) and with sinus rhythm (SR) and atrial fibrillation (AF). 194 patients after successful introduction of CRT device were evaluated. Evaluation of NYHA function class, QRS width and echocardiographic parameters including parameters of left ventricle contraction dyssynchrony (SPWMD: septal-to-posterior wall motion delay, Ts-sep-lat: time interval between maximum of systolic movement of septum and lateral wall using tissue Doppler imaging, IVMD: interventricular mechanical delay) performed before implantation and 3 months after implantation of CRT device. Responder (improved in NYHA class after CRT) rate was 61%. SR patients showed higher benefit compared to AF patients (responder rate 63% vs. 52%, p<0.05). Narrowing of QRS width after CRT was observed only in responders. SPWMD and Ts-sep-lat decreased after CRT in all subgroups. SPWMD dyssynchrony (SPMWD > or = 130 ms) reduction after CRT was more expressed in niCMP population. Ts-sep-lat dyssynchrony (Ts-sep-lat > or = 65 ms) reduction after CRT was more expressed in SR patients. IVMD (IVMD > or = 60 ms) remained unchanged in average, but significant decrease was observed in responders and significant increase in non-responders. QRS width, SPWMD and Ts-sep-lat showed moderate sensitivity but poor specificity to predict CRT benefit. QRS width > or = 150 ms in niCMP patients showed higher sensitivity to predict CRT effect compared to iCMP patients (91%, 65% respectively). IVMD showed poor sensitivity but good specificity to predict CRT benefit. IVMD in SR patients (compared to AF patients) showed higher specificity to predict CRT effect (90%, 63% respectively). None of tested left ventricle contraction dyssynchrony parameters showed good sensitivity and specificity to predict CRT benefit. QRS width as a predictor factor was more beneficial in non-ischemic patients and IVMD in sinus rhythm patients.
Highlights
Biventricular pacing as a modality of cardiac resynchronization therapy is already a common non-pharmacologic treatment of drug-resistant heart failure in patients with left ventricle contraction dysfunction and left ventricle contraction dyssynchrony
We found no differences between ischemic cardiomyopathy (iCMP) and non-ischemic CMP (niCMP)
In our group of patients, basal SPWMD did not differ between responders and non-responders (p = 0.17) in concordance with THE PROSPECT Study, but we proved no difference between patients with vs. without left ventricle ejection fraction (LVEF), LVEDD or LVESD reduction after cardiac resynchronization therapy (CRT) (p = 0.7, p = 0.13 and p = 0.08 respectively)
Summary
Biventricular pacing as a modality of cardiac resynchronization therapy is already a common non-pharmacologic treatment of drug-resistant heart failure in patients with left ventricle contraction dysfunction and left ventricle contraction dyssynchrony (thereinafter dyssynchrony). Following the classical indication criteria does not lead to positive response to CRT in 30–40% of patients[10]. The reason of such a high number of so called “non-responders” is multifactorial – including labile relationship between electrical (QRS width) and mechanical dyssynchrony[11], influence of other factors such as myocardial ischemia and presence of fibrous tissue, final lead position, concomitant diseases and arrhythmias etc. A number of trials have demonstrated the effect of cardiac resynchronization therapy (CRT) on functional improvement and reversed left ventricle remodeling. Meeting contemporary guidelines approximately 3040% of patients do not respond to CRT (non-responders)
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