Deaths in long-term paced patients.

Abstract

Full analysis of the incidence ofsudden unexplained death shows it to be no more common when fixed rate pacemakers compete with inherent beats than in the absence of competition.In I3 years (i960/I972), 77I patients have been paced on a long-term basis at St. George's Hospital, all but 27 for complete atrioventricular block. Since I962 our standard method has been with an implanted pacemaker and a transvenous endocardial electrode. This paper reports the survival rate of patients with complete block paced by this method and the causes of the deaths.Of the total series, 649 were paced by an implant with a transvenous endocardial electrode. Some of these also underwent a period of pacing with myocardial electrodes placed on the heart at operation and some were paced for periods with an endocardial electrode with the lead brought through the skin to an external pacemaker. Such patients are included in the survival statistics but only the deaths occurring while pacing with an implant and transvenous electrode are analysed here. The series included 375 men and 274 women. The age distribution is shown on the histogram (Fig. i). Of the pacemakers used in this series, 93 per cent were manufactured by Devices Ltd. The remainder covers a wide variety ofpacemakers made in the U.S.A., Sweden, Holland, and West Germany. Survival comparisonsThe survival curve is seen in Fig. 2, which also indicates the survival of 113 unpaced patients with complete atrioventricular block, and the expectation of life of the population of England and Wales matched with the paced series for age and sex (latest available figures I96I). Our series of II3 Received I3 May 1974. unpaced patients was collected before artificial pacing was introduced and in the early days of pacing (I960 to I965) when pacing was relatively unreliable. These unpaced patients include all patients with complete block seen in the department over this period and their mean age and sex distribution does not differ grossly from the paced series. They must, however, be considered as a selected

Physiologic pacing in the elderly. Effects on exercise capacity and exercise-induced arrhythmias.

“…Ventricular rhythm disturbances are important in paced patients, as an important subgroup dies suddenly.17) Ventricular arrhythmias have been found in more than 50% of patients during exercise testing, even with ventricular demand pacing.18) It has been claimed that physiologic pacing could reduce the importance of arrhythmias, but only scarce evidence has been reported.12),18), 19) We could not demonstrate an excess nor a reduction of ventricular arrhythmias during exercise with physiologic stimulation, in a population prone to the development of ventricular rhythm disturbances and sudden death.6), 17) Implantation of single-chamber systems with the possibility of rateadaptation during exercise certainly avoids technical problems and remains possible when atrial arrhythmias exist, but programming is not always easy.…”

Age, sex, and ischaemic heart disease as prognostic indicators in long-term cardiac pacing.

“…The inclusion of some patients (6% of those paced) with sinuatrial disorder is unlikely to have improved the prognosis of the study group as a whole (Wohl et al, 1976;Shaw et al, 1978). Neither is the initial use of asynchronous generators likely to have had a statistically significant effect on survival (Siddons, 1974) though 'demand' systems are now preferred because of the frequency of emergent, potentially competitive, rhythms even in those apparently in stable, complete heart block at the time of generator implantation (Grover et al, 1974;Furman and Fisher, 1977). In contrast with the findings of Amikam et al (1976), this study indicates a better than average prognosis for women paced after the age of 54 years.…”

Prevalence, circumstances, mechanisms, and risk stratification of sudden cardiac death in unipolar single-chamber ventricular pacing.

“…[13][14][15][16][17][18][19][20][21][22] In this study, which was designed to obtain previously lacking data on prevalence and modalities of sudden death in a larger group of patients, artificial pacing was associated with a 23% prevalence of sudden and unexpected cardiac death. The fatal event occurred with similar prevalence during all types of physical and sedentary activities.…”