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His bundle electrograms were obtained in 313 patients with chronic bundle branch block who were followed for a mean period of almost 3 years. The infranodal conduction time (H-Q interval) was less than 55 ms in 97 patients (Group I), 55 to 69 ms in 99 patients (Group II), and greater than or equal to 70 ms in 117 patients (Group III). There was a higher incidence of organic heart disease in patients in Group III, but the groups were otherwise comparable. On follow-up study, mortality and the incidence of sudden death were similar among the groups, but patients in Group III had a greater incidence of progression to high degree atrioventricular block (HDB) than did those in Groups I and II (14 of 117 [12%] versus 4 of 97 [4%] and 2 of 99 [2%], p less than 0.01, respectively). High degree block was found in 4 of 17 (24%) patients with an H-Q interval (H-Q) greater than or equal to 100 ms. Sixty-two patients underwent permanent prophylactic pacemaker insertion at the discretion of the referring physician and were compared with 231 patients who did not. Paced patients had a higher incidence of transient neurologic symptoms and prolonged H-Q, but the groups were otherwise comparable. On follow-up study, mortality and the incidence of sudden death were similar among the groups, but symptom relief was significantly more common among patients with pacemakers. In conclusion, in our population (1) H-Q greater than or equal to 70 ms was an independent risk factor for progression to HDB, (2) H-Q greater than or equal to 100 ms identified a subgroup at particularly high risk, and (3) prophylactic pacemakers relieved neurologic symptoms but did not prolong life.

To assess changes in left ventricular function during antihypertensive treatment using pindolol, a beta-adrenocepter blocking drug with potent intrinsic sympathomimetic activity, serial echocardiographic measurements were obtained in 70 hypertensive patients before and during 15 weeks of treatment with pindolol. For analysis, the patients were separated into three groups on the basis of their baseline left ventricular fractional shortening (Group I, 35 patients with normal fractional shortening of 28 percent or more; Group II, 16 patients with abnormal fractional shortening of 21 to 27 percent; and Group III, 19 patients with markedly abnormal fractional shortening of 20 percent or less). More than half of the patients in Group I and Group II had decreases in mean blood pressure of 10 percent or more in response to pindolol, but only one fourth of Group III patients had similar responses (p less than 0.05). Patients with normal pretreatment fractional shortening had a mild decrease in fractional shortening during pindolol treatment, whereas patients with either abnormal or markedly abnormal fractional shortening had an increase in fractional shortening. This increase in fractional shortening suggests the possibility that the partial agonist or intrinsic sympathomimetic activity of pindolol may play a role in preserving left ventricular function in patients with borderline or impaired function.

Late pacemaker pocket infections in the absence of predisposing factors such as multiple pacemaker related procedures, skin erosion, chest wall trauma or generalized sepsis have been rarely reported. In the past year, we have seen three late pocket infections (18, 32 and 47 months post-implantation) due to Staphylococcus epidermidis (S. epidermidis). All three patients with late S. epidermidis infections presented with painless swelling over the pulse generator site and had been well until shortly before admission. The patients denied febrile illnesses or chest trauma in the preceding year and no skin erosion was evident. All had been seen regularly in clinic and bimonthly transtelephonic recordings had shown normal pacemaker function. Local drainage, antibiotics and removal of the pacing system was successful in all three patients. We conclude that late pacemaker pocket infections due to S. epidermidis may become an important clinical problem in this era of long-lasting pulse generators. In light of the insidious nature of S. epidermidis infections, regular inspection of the pocket area by both patient and physician is mandatory.