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Biomedical subjects

H Siddons

Publications and source records attributed to H Siddons.

At least 19 recordsLinked to original sources

Unsuspected coronary artery disease as cause of chronic atrioventricular block in middle age.

Attention has recently been drawn to the relatively poor prognosis of middle aged patients paced for chronic atrioventricular block when age-linked expectation of life is taken into account, and it has been suggested that this may be the result of underlying coronary artery disease, despite the absence of symptoms to suggest this. It was the purpose of this study to determine the incidence of unsuspected coronary artery disease in middle aged patients presenting with chronic atrioventricular block. Studies were made on a consecutive series of 30 patients aged 45 to 65 (mean age 56 years) with chronic atrioventricular disease who had been referred for pacing. Patients presenting with acute myocardial infarction or angina or with sinuatrial disease without atrioventricular disease were excluded. Coronary arteriography disclosed the presence of severe coronary artery disease in 13 patients. Of the remaining 17 patients, four had congestive cardiomyopathy, two had hypertrophic cardiomyopathy, one had aortic stenosis, and in 10 patients the aetiology of the heart block was unknown. Myocardial revascularisation was undertaken in six patients with paroxysmal atrioventricular block caused by coronary artery disease. Operation did not result in any sustained improvement in atrioventricular conduction.

Aged↗

Septicemia in patients with an endocardial pacemaker.

The records of 1,235 consecutive patients treated with long-term pacing by the endocardial route between 1964 and 1977 were analyzed to determine the incidence, mechanism, course and treatment of septicemia. Septicemia developed in 12 patients (1 percent), and Staphylococcus aureus was isolated from the blood culture in 10. All patients were treated with the usual prolonged course of bactericidal drugs. Treatment was successful in only two of the seven patients whose endocardial pacing system was left in place; in three of the seven the septicemia recurred, necessitating removal of the endocardial system, and two of these patients died. In the remaining four patients the endocardial wire was promptly withdrawn, with use of a thoracotomy when necessary, and an epicardial system inserted; all of these patients survived. This is the treatment of choice.

Adult↗

Prognosis of patients paced for chronic atrioventricular block.

Between the years 1960 and 1974, 839 patients were paced for chronic complete atrioventricular block. Analysis of survival compared with the general population showed that 170 deaths were expected according to standard mortality tables and 288 actually occurred, giving a ratio of actual to expected deaths of 1.7:1. Patients with a definite history of myocardial infarction showed a higher than average mortality when paced. Mortality was not influenced whether heart was constant or intermittent, whether the ventricular rate was below or above 40/minutes, or whether QRS duration was greater or less than 0.1 second. Analysis of the age groups paced disclosed the most important correlations. Between the ages of 80 and 89 years paced patients could expect to survive as long as other of the same age without heart block. There was, however, a very high ratio of 4.5:1 for 90 patients in the age group 50 to 59 years. The reason for the high mortality ratio was uncertain but it may have been the result of a greater incidence of underlying coronary artery disease.

Age Factors↗

Transvenous long-term pacing with an external pacemaker. What are the risks?

Externalized endocardial electrodes were used for pacing 138 patients for periods of one month to 12 years. In the 416 patient/years of pacing by this method, 13 septicemias occurred. Implanted pacemakers with endocardial electrodes were used in 1186 patients. In the 3488 patient/years 11 septicemias occurred. The mortality and an assessment of the cause of death for pacing by the two methods is presented. It is concluded that the external method of transvenous pacing carries additional risk and is only justified in special circumstances.

Cardiac Pacing, Artificial↗

Deep vein thrombosis after thoracotomy.

In a prospective study of 183 patients undergoing lateral thoracotomy the 125 I fibrinogen uptake test and perioperative heparin prophylaxis for deep-vein thrombosis were investigated. There was an incidence of deep vein thrombosis in 51% in untreated control patients. The heparin prophylaxis effectively reduced the incidence of deep venous thrombosis to 28% (P less than 0.005) without increasing postoperative blood loss. Unilateral thrombosis was found to be significantly more frequent in the leg opposite the side of the thoracotomy (P less than 0.005). The 125I fibrinogen test is essential in assessing methods of prophylaxis but is not recommended as a routine.

Female↗

Surgical complications of implanting pacemakers.

An analysis of the complications of implanting pacemakers at St George's Hospital between 1967 and 1973 highlights the difficulties of implanting foreign bodies. During this 7 years 1543 pacemakers were implanted in 779 adults. In 91 patients there were 118 implants with surgical complications, most of them due to a pressure necrosis or local infection; 3 septicaemias occurred. The various complications are classified and related to technique of implantation. Methods of management of the complications are presented. As an Appendix the operative techniques of first and subsequent implantations are outlined.

Female↗