CardioInsight 3 - LBBB (CardioInsight3)

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, being nonresponder is observed in up to 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 no response to CRT. Purpose of the clinical investigation The purpose of the Activation Pattern and Acute Hemodynamics of His and Left Bundle Pacing is to study the acute effect on the heart function and conduction abnormality of His and left bundle pacing in conventional CRT candidate. During CRT implantation, Hisbundle lead and Left bundle pacing lead will be placed and the acute effect on heart function will be studied by a wire placed in the left ventricle of the heart and the activation pattern will be studied by a noninvasive global mapping system. The pacing approach that optimally corrects conduction abnormality and improvement on the heart function acutely will be determined

To study the feasibility to optimize configuration of CRT delivery for acute correction of electrical dyssynchrony using a noninvasive mapping of global electrical activation

Correction of activation abnormality as evaluated by global noninvasive mapping system (ECGi) seen as an increase in acute dp/dt > 5% from baseline with left bundle pacing comparing to biventricular pacing.

Procedure duration of the optimal CRT delivery method as determined by the best improvement in electrical desynchrony indices.

Implantation success rate of the optimal CRT delivery method as determined by the best improvement in electrical desynchrony indices.

Cine images (PA, LAO 300, RAO 300) and Chest X ray (PA view) obtained during course of study for assessment of disease

Echocardiogram parameters: left ventricular systolic and diastolic volume at baseline, 3 months and 6 months

Comparison of NYHA class at baseline, 3 months and 6 months to assess changes in quality of life of subject.

Peri-operative and 6 months follow-up complications rate: Thromboembolic event Dislodgement and migration of pacing leads Phrenic nerve stimulation Others

Electrical parameters including lead impedance of pacing leads at addition of new lead and 6 months follow-up.

Comparison of 6 minute hall walk test result at baseline, 3 months and 6 months to assess changes in quality of life of subject.

Comparison of HF Patient Global Assessment Questionnaire outcome at baseline, 3 months and 6 months to assess changes in quality of life of subject.

Inclusion Criteria: Adult (aged 18 or above) of both sexes Candidate for CRT therapy according to international guidelines.7 Informed consent by the patient Already received stable dose of guideline directed medical therapy for at least 3 months Exclusion Criteria: Pregnant Participating in another study