Prevalence of potential candidates for biventricular pacing among patientswith known coronary artery disease: A Prospective Registry from a Single Center

A Prospective Registry from a Single Center. New forms of ventricular pacin g are increasingly studied as an option in the management of patients with heart failure. Coronary artery disease (CAD) is the most frequent cause of heart failure, and patients with complete left or right bundle branch block (LBBB and RBBB) and a reduced left ventricular ejection fraction (LVEF) ar e the best candidates for this new therapy. However, the prevalence of this clinical presentation is uncertain. During a 1-year period, 433 patients w ith documented CAD (mean age 64 +/- 10 years, 79% men) who were referred fo r myocardial perfusion imaging were prospectively studied. All patients und erwent a 2-day stress-rest gated Tc-99m-Tetrofosmin SPECT study with evalua tion of resting LV enddiastolic (LVEDV) and endsystolic (LVESV) volumes and LVEF. The resting ECG was examined in all patients for the presence of com plete LBBB or RBBB. Of the 433 patients with CAD 36 patients (8.3%) had LBB B (n = 14) or RBBB (n = 22) and a QRS width >120 ms. These 36 patients were in general older and more ly had diabetes and atrial fibrillation. Patient s with LBBB or RBBB had a significantly lower LVEF (41 +/- 16% vs 48 +/- 14 %, P < 0.01) and significantly higher LV volumes compared to patients witho ut LBBB or RBBB (177 +/- 79 mL vs 131 +/- 53 mL, P < 0.001 for LVEDV and 11 6 +/- 76 mL vs 73 +/- 49 mL, P < 0.001 for LVESV). In total, 112/433 (26%) had an LVEF <less than or equal to> 40%; 16 had also a LBBB or RBBB (3.7% o f the whole population, 14% of the patients with a LVEF less than or equal to 40%). Within the group of patients with a LVEF greater than or equal to 40%, patients with BBB had comparable LVEF (26 +/- 9% vs 30 +/- 8%, P = NS) but significantly higher LVEDV and LVESV (230 +/- 70 mL vs 190 +/- 64 mL, P < 0.05 for LVEDV and 170 +/- 65 mL vs 135 +/- 56 mL, P < 0.05 for LVESV). in this prospective registry 3.7% of all patients with known CAD had LBBB or RBBB in combination with a LVEF less than or equal to 40%. This represen ted 14% of all patients with a LVEF greater than or equal to 40%. These lim ited numbers should be kept in mind when considering biventricular pacing a s a new therapeutic options in patients with heart failure.