Objectiye To evaluate the accuracy and practicability of detecting viable myocardium by CARTO voltage mapping in swine model of acute myocardial infarction(MI). Methods MI was induced in 13 anesthetized swines via occluding the distal of left anterior descending coronary arteries by angioplasty balloon for 60-90 minutes. The viable myocardium detection by CARTO voltage mapping was made after reconstruction of the left ventricle using CARTO and the results were compared with TTC staining. The standard of CARTO voltage to detect viable myocardium was 0. 5 - 1.5 mV while viable myocardium showed pink color by TTC staining. Results Eleven out of 13 swines survived the operation and 2 swines died of ventricular fibrillation at 45 and 65 minutes post ischemia. Left ventricle was divided into 16 segments and 176 segments from 11 swines were analyzed. Viable myocardium detected by CARTO voltage mapping was identical as identified by TTC staining(Kappa =0. 816,P ＜0. 001). Taken the TTC result as standard, the sensitivity, specificity and accuracy rate of CARTO voltage mapping are 71.8%, 96.5% and 90.9%respectively. Conclusion CARTO voltage mapping could be used as a reliable tool to detect viable myocardium in this model.

Objective To observe the efficacy of cardiac resynchronization therapy for patients with refractory congestive heart failure. Methods Thirty-one patients with refractory congestive heart failure received cardiac resynchronization therapy. Before operation, all patients received standard drug therapy (28 cases) or integrated with CRRT (3 cases). Coronary sinus and its branches were shown by direct angiography with hollow angiographic catheter(11 cases)and by balloon angiographic catheter (20 cases). Left ventricle and right ventricle electrodes were implanted to 3 patients with atrial fibrillation, 4 patients with paroxysmal ventricular tachycardia or ventricular fibrillation received CRT-D implantation. electrocardiogram, 24 hours Holter, echocardiography and physical clinical examinations were made at baseline, 6, 12,18 and 24 months post resynchronization therapy. Results Pacemakers were successfully implanted in all 31 patients. One patient implanted with CRT-D died of multiple organ failure on third day after operation, 1 patient suffered sudden cardiac death 5 months after therapy and 2 patients were lost to fellow up 6 and 12 months after operation, respectively. Results from the remaining 27 patients showed that QRS duration was significantly decreased ( 153±8.4 at baseline vs. 132±9.8 at 24 months follow up) and cardiac function significantly improved (LVEF 0.29±0.10 at baseline vs. 0.41±0.11 at 24 months follow up, P<0.05 vs. baseline) during follow up compared to baseline. Malignant ventricular arrhythmia occurred in 3 patients with CRT-D and successfully terminated and converted to sinus rhythm. Conclusions Cardiac resynchronization therapy could improve cardiac function for patients with refractory congestive heart failure. CRT-D can effectively terminate the malignant ventricular arrhythmia.