No major differences were identified in systolic function between pacing sites. Some systolic parameters were better preserved with outflow tract pacing and diastolic function deteriorated subtly over time in both groups. Right ventricular pacing adversely affects left ventricular function.

Objectives: While carotid sinus syndrome (CSS) is traditionally defined by the association of carotid sinus hypersensitivity (CSH) with syncope, uncertainty remains over the role, if any, of complex pacing in patients with CSH and unexplained or recurrent falls. We sought to clarify the role of dual chamber pacing in this patient group in the first placebo-controlled study in CSH. Design: Randomised, double-blind, crossover, placebocontrolled trial. Setting: Specialist falls and syncope facility. Patients: Consecutive subjects aged over 55 years with CSH as the sole attributable cause of three or more unexplained falls in the 6 months preceding enrolment. Intervention: Dual-chamber permanent pacing with ratedrop response programming. The pacemaker was switched on (DDD/RDR) or off (ODO (placebo)) for 6 months, then crossed over to the alternate mode for a further 6 months, in randomised, double-blind fashion. Main outcome measure: The primary outcome measure was number of falls in paced and non-paced modes. Results: Twenty-five of 34 subjects (mean 76.8 years (SD 9.0), 27 (79%) female) recruited completed the study. Pacing intervention had no effect on number of falls (4.04 (9.54) in DDD/RDR mode, 3.48 (7.22) in ODO; relative risk of falling in ODO mode 0.82, 95% CI 0.62 to 1.10). Conclusion: Permanent pacing intervention had no effect on fall rates in older patients with CSH. Further work is urgently needed to clarify the role, if any, of complex pacing in this patient group.

Background-Pacemaker pocket infection is a potentially serious problem after permanent pacemaker implantation. Antibiotic prophylaxis is commonly prescribed to reduce the incidence of this complication, but current trial evidence of its efficacy is conflicting. A large prospective randomised trial was therefore performed of antibiotic prophylaxis in permanent pacemaker implantation. The intention was firstly to determine whether antibiotic prophylaxis is efficacious in these patients and secondly to identify which patients are at the highest risk of infection. Methods-A prospective randomised open trial of flucloxacillin (clindamycin if the patient was allergic to penicillin) v no antibiotic was performed in a cohort of patients undergoing first implantation of a permanent pacing system over a 17 month period. Intravenous antibiotics were started at the time of implantation and continued for 48 hours. The trial endpoint was a repeat operation for an infective complication. Results-473 patients were entered into a randomised trial. 224 received antibiotic prophylaxis and 249 received no antibiotics. A further 183 patients were not randomised but were treated according to the operator's preference (64 antibiotics, 119 no antibiotics); these patients are included only in the analysis of predictors ofinfection. Patients were followed up for a mean (SD) of 19(5) months. Among the patients in the randomised group there were nine infections requiring a repeat operation, all in the group not receiving antibiotic (P = 0.003). In the total patient cohort there were 13 infections, all but one in the non-antibiotic group (P = 0.006).

Objectives-To increase awareness of the potential for disabling anxiety and depression in patients receiving shocks from implanted cardioverter-defibrillators (ICDs). Patients and methods-ICDs are implanted in patients at this hospital for control of serious ventricular tachyarrhythmias inadequately controlled by drug treatment, who are unsuitable for map guided antiarrhythmic surgery. All are reviewed regularly at a dedicated ICD clinic and are advised to make contact between visits if they experience shocks. Symptoms of anxiety or depression were not actively sought, nor was a patient support group operating at the time of this data collection. When overt psychopathology was identified, patients were referred to a designated psychiatrist for management. Results-Over a six year period, six (17%) of 35 patients with ICDs developed florid psychiatric problems after experiencing shocks. None had premorbid psychiatric predisposition. Of the six patients suVering severe psychiatric problems, four were men, their age range was 30-63 years, and left ventricular ejection fraction was 18-40%. All shocks were appropriate for clinical arrhythmias and ranged in frequency from two in six months to 111 in 24 hours. All six patients manifested severe anxiety, focused on fear of future shocks. Depression was also evident in three patients and two had become housebound. All responded within weeks to anxiolytic or antidepressant drugs, combined with relaxation and cognitive therapies. Ongoing psychiatric therapy was refused by one patient, and was required for between three and 18 months in the remainder. One patient died and one received a cardiac transplant during the follow up period (median 27.5 months, range 8-43). Conclusions-Because ICD implantation occurs against a complex medical background with inevitable psychological stress, all such patients should be considered at high risk for developing psychopathology.

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