CardioInsight 2 - Non-responder (CardioInsight2)

Electrical Activation Mapping Guided Tailor Made Approach for Cardiac Resynchronization Therapy for Non-responder

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 Electrical Activation Guided CRT for Nonresponders Study is to study the effectiveness of an addition of Hisbundle pacing approach to CRT nonresponder by direct His-bundle pacing to improve the responder rate of nonresponder of conventional CRT and 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 addition of new lead procedure. Conduct of the Investigation This study will include 18 patients already implanted with device delivering conventional CRT that known to have no response to the conventional CRT after 6 months of the CRT therapy from Prince of Wales Hospital, Hong Kong. You will be followed in the device clinic as per usual care after your participation in the study is completed.

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

The responder rate of greater than 10% of LV end systolic volume reduction measured by echocardiogram.

The acute electrical desynchrony indices (the standard deviation of activation times throughout the epicardium) of different methods of CRT delivery. Lower indicate larger improvement.

Monitor the difference in hemodynamic responses of different methods of CRT delivery. The hemodynamic response will be maximal dp/dt as measured by pressure wire introduced into the left ventricle during the procedure.

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) of patients will be obtained for evaluation of changes in disease

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

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

Change in quality of life assessed by Minnesota's living with heart failure (MLWHF) questionnaire at baseline, 3 months and 6 months.

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 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