electrical activation mapping guided tailor made approach for cardiac resynchronization therapy

Conditions: Heart Failure

Summary: background cardiac resynchronization therapy (crt) is proven to improve survival and heart function of patient with certain electrical conduction abnormality and heart failure. however, in patient with certain electrical conduction abnormality, a good response is observed in less than 40% in patient receiving crt. conventionally the surgical approach of crt is to implant one pacing lead in the right heart and one in the left heart to resynchronize the contraction and the pacing lead in the left heart is usually placed in the posterior or lateral portion of the left heart. however, this single approach may not be optimal, especially for those patients with conduction abnormality known to have poor response to crt. purpose of the clinical investigation the purpose of the electrical activation guided crt study is to study the effectiveness of a tailored made approach to crt procedure by using a noninvasive globally mapping system studying the electrical conduction under different approaches to delivery crt. the pacing approach that optimally corrects conduction abnormality will be determined before the actual implantation procedure. conduct of the investigation this study will include 93 patients with conduction abnormality that known to have a poor response to crt from prince of wales hospital, hong kong.subjects will be followed up at 3 months and 6 months visit.

the purpose is to prospectively study the feasibility to optimize configuration of crt delivery for acute correction of electrical dyssynchrony using a noninvasive mapping of global electrical activation. study hypothesis: tailor-made configuration of crt delivery is feasible and able to improve responder rate compare to single method of crt delivery in candidates with known poor response to crt. primary outcome measure: responder rate of greater than 10% of lv end systolic volume reduction in patients undergoing tailor-made approach of crt delivery at 6 months. the responder rate is to compare with pre-defined level of 40% for single method of crt delivery namely biventricular pacing with lv lead in coronary sinus. sample size: the total required sample size is 93 patients with device implanted.

Eligibility criteria:
inclusion criteria: * adult (aged 18 or above) of both sexes * ischemic or non-ischemic cause of heart failure * qrs duration \> 120 ms, non -lbbb type of conduction disturbance * nyha class iii or above * sinus rhythm * informed consent by the patient * already received stable dose of guideline directed medical therapy for at least 3 months exclusion criteria: * lbbb\* patients * pregnant women * participation in another study * patient with contraindication to left ventricle catheterization by a retrograde aortic approach (eg mechanical aortic valve, severe aortic stenosis and aortic dissection) \*the definitions of lbbb (qrs duration ≥130 ms; qs or rs in lead v1; broad r waves in leads i, avl, v5, or v6; and absent q waves in leads i, v5, and v6).

Keywords: cardiac resynchronizaton therapy electrical activation mapping noninvasive electrical dyssynchrony