Biomedical subjects
Publications and source records attributed to T Treasure.
A pericardiocutaneous fistula five years after repair of a rupture of the ventricular septum was managed by removing all foreign material (Teflon). The resulting defect was repaired with part of the central tendon of the diaphragm and a pedicle of omentum was used to cover the heart. This radical approach was found necessary after other measures, including surgical excision of the fistula, had failed.
We have investigated the influence of ventricular loading on repolarization from beat to beat in the human heart. Sixteen patients undergoing routine coronary artery surgery were studied. Left ventricular epicardial monophasic action potentials and local electrograms were recorded during acute changes in ventricular loading induced by transient aortic occlusion. Monophasic action potential duration shortened (P less than 0.0001) and returned to control values within one or two beats after release (P less than 0.0001). Values at 90% repolarization were 325 +/- 31 ms preocclusion, 311 +/- 29 ms during occlusion, 326 +/- 32 ms postocclusion. The Q-T interval of the local epicardial electrogram shortened during occlusion (P less than 0.001) and returned to control values after release (P greater than 0.0001): 396 +/- 44 ms preocclusion, 379 +/- 41 ms during occlusion, and, 399 +/- 42 ms postocclusion. A significant correlation was obtained between changes in peak systolic pressure and changes in monophasic action potential duration (R = 0.96; P less than 0.0001 at 90% repolarization). A significant correlation was also observed between changes in peak systolic pressure and the Q-T interval of the local electrogram (R = 0.91; P less than 0.0001). This study shows that abrupt changes in ventricular loading from one beat to the next induce significant changes in the timing of ventricular repolarization. These results may well be relevant to the initiation of arrhythmia by a single ventricular ectopic beat, particularly under pathological conditions.
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False aneurysm of the internal mammary artery is an uncommon complication of median sternotomy. Clinical and radiological findings of 2 such cases are presented. At operative exploration neither was directly related to the presence of a sternal wire.
Electrophysiological alternans (beat-to-beat alternation of the configuration of the action potential and/or electrocardiogram) may be important in the causation of ventricular arrhythmias. We recorded monophasic action potentials from the left ventricular epicardium in patients undergoing routine cardiac surgery. We set out to determine: (a) whether a small increase in atrial pacing rate could elicit electrophysiological alternans; (b) whether different phases of the operation influence the incidence and; (c) whether electrical alternans was a localized phenomenon. Thirty-six patients were studied, and alternans of action potential duration was observed in 14 (39%). The difference between alternate long and short action potential durations ranged from 4 to 112 ms. The mean differences during each stage of the protocol were: pacing before bypass 33.3 +/- 22.7 ms (three of 17 patients); pacing after bypass 46.7 +/- 37.8 ms (nine of 36 patients); pacing during transient graft occlusion 28.0 +/- 23.1 ms (five of 17 patients); pacing following release of the grafts 29.6 +/- 30.0 ms (five of 17 patients). None of the patients showed any evidence of alternans in the electrocardiogram or mechanical alternans in radial artery pressure. In seven of the 14 patients showing alternans, recordings were made in closely adjacent (approximately 1 cm) areas showing that alternans could be a localized phenomenon. The findings indicate that electrical alternans was a frequent occurrence in this study (39% of patients) and may be a localized phenomenon.
Fifty cases of aortic valve endocarditis during a 6-year period between 1982 and 1988 were reviewed. Twenty-three (46%) had aortic root complications by way of aortic root abscess or mycotic aneurysm in the perivalvular area. Patients with root complications were grouped into the aortic root abscess (ARA) group and those without into a non root abscess (NARA) group. Prosthetic valve endocarditis dominated in the ARA group (12 and four cases of prosthetic valve infection in the ARA and NARA groups, respectively; P less than 0.01). Surgical mortality was significantly higher at 13.6% in the ARA group as opposed to 2.2% in the NARA group (P less than 0.05). Post-operative aortic regurgitation was present in 8 (57%) of 14 patients in the ARA group surviving surgery but in only two (8.7%) of 23 patients in the NARA group (P less than 0.03). We conclude that aortic root complications are a frequent occurrence in aortic valve endocarditis, lead to an increased operative mortality and is associated with a high incidence of post-operative aortic regurgitation.
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We have reviewed experience with aminoglycosides in cardiac surgical prophylaxis from 1984 to 1989. In the first two years, prospectively randomized trials (517 patients) allowed comparison of tobramycin (three-day course) with a non-toxic antibiotic, teicoplanin. A significant excess rise in serum creatinine was present at the end of the first postoperative week in patients given tobramycin (165 vs 149 patients, 95% CI 3-17 microM. P less than 0.01, which was most marked in ten oliguric patients with trough serum levels over 2 mg/l (95% CI 7-52 microM). However, no patient needed haemodialysis and only one case of possible ototoxicity was identified. During the next three years, of 912 patients given two to three days gentamicin, 29 patients were shown to have potentially toxic serum levels and oliguria. Three individual cases are described, including one of ototoxicity and one of nephrotoxicity neeeding haemodialysis. The hazards of aminoglycoside toxicity are probably small compared with the failure of other antibiotics to cover staphylococci that may later cause wound infection or endocarditis. However, surgeons should probably be advised to check the aminoglycoside level in all patients on the first post-operative day.
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In some hospitals all the coronary surgery that can be managed is confined to keeping up with emergencies and urgent cases. Increasingly surgical effort is extended to difficult cases for marginal benefit. Should the surgeon and cardiologist turn their backs on the seriously ill and treat more cost-effective cases?
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