| Abstract: | His bundle recordings were obtained in 189 patients with chronic bundle branch block, and the patients were followed for a mean of approximately 20 months. Forty patients underwent prophylactic pacemaker insertion (group II) and 149 did not (group I). There was no significant difference between the two groups at the time of entry into the study with regard to mean age, serum cholesterol or the incidence of smoking, diabetes, hypertension, coronary artery disease or congestive heart failure. The patients in group II had a significantly higher incidence of transient neurologic symptoms (30 of 40,75 per cent, versus 79 of 149, 53 per cent, p < 0.05) and longer mean infranodal conduction time (79 ± 25 versus 61 ± 20 msec, p < 0.001). Eleven patients died before symptom relief could be assessed. More paced patients (group II) had relief of neurologic symptoms compared with the unpaced group (18 of 25, 72 per cent, versus 36 of 73, 49 per cent), but the difference was not quite statistically significant (0.1 <p > 0.05). There was no significant difference between the two groups in the total mortality or the incidence of sudden death. Nineteen of 21 sudden deaths occurred in patients with coronary artery disease and/or congestive heart failure.In conclusion, (1) prophylactic pacemaker insertion in a subset of largely symptomatic patients with chronic bundle branch block and long H-Q time did not protect against sudden death; the incidence of this complication appears to be related to the type and severity of underlying heart disease; (2) presenting neurologic symptoms may be an inadequate guide to assess the need for permanent pacing in bundle branch block. |
