Electrical restitution in diseased human ventricular myocardium.

Action potential configuration and electrical restitution were studied in diseased human ventricular muscle by comparing the characteristics of hypertrophic (HYP) and dilated (DIL) human ventricular preparations. Conventional microelectrode techniques were used to evaluate action potentials evoked at increasingly longer diastolic intervals. The steady-state action potential duration (APD90) was significantly longer in DIL than in HYP preparations (393 +/- 5 ms, n = 4 and 296 +/- 11 ms, n = 4, respectively; P < 0.001, mean +/- SEM). In the dilated preparations studied at long diastolic intervals, the initial period of rapid repolarization (phase 1) was absent, and the rate of final repolarization (phase 3) was reduced. Electrical restitution relations in these preparations were fitted as the sum of two exponentials. The time constant of the fast component was significantly longer in DIL than in HYP preparations (242 +/- 9 ms and 121 +/- 4 ms, respectively; P < 0.001). No difference was observed in the time constants for the slow component of restitution in the two groups. Electrical restitution was also studied in single human ventricular myocytes by using patch clamp techniques. The initial 600 ms period of restitution was fitted in these cells to a monoexponential function. The time constant for this period of the restitution relation was significantly longer, while the estimated amplitude of this early rising phase was significantly lower in human cells obtained from DIL hearts than the respective parameters obtained in the healthy canine and guinea pig cells also examined. The observed changes in the restitution kinetics of the dilated human heart are, likely, the consequence of alterations in the ionic currents that underlie the cardiac action potential.

[PGI2-like activity of the internal mammary artery and the saphenous vein used in coronary bypass surgery]. / Coronaria bypass mütéteknél alkalmazott arteria mammaria interna és a vena saphena PGI2-analóg aktivitásának tanulmányozása.

The best graft in coronary bypass operations is the internal mammary artery as its rate of staying open for long term is better than that of saphenous vein. The prostacyclin-producing capacity of these human blood vessels was studied using platelet aggregation bioassay. The synthesis of prostacyclin-analogous was significant higher in internal mammary artery than that was in saphenous vein (in 10 min of incubation time internal mammary artery: 73.33; saphenous vein: 42.27 pg/mg). Based on our results we conclude that the difference of "prostacyclin-like" activity between artery and vein might play a role, at least partly, in the more successful operations performed with internal mammary artery.

[Direct revascularization of the myocardium using the internal mammary artery]. / A szívizom direkt revascularisatiója az arteria mammaria interna felhasználásával.

The best graft in coronary bypass operations is the internal mammary artery (IMA) as its rate of staying open for long term is better than that of the vena saphena magna. The authors present the operative and postoperative results of their first 161 patients who were subjected to IMA grafting. 126 were men and 35 women of the patients and the average age was 50.2 years. Before the operation the majority of the patients belonged to NYHA III state (69.6%). 86 patients (53.4%) had myocardial infarction before the operation, 50.3% were operated on because of 3 blood vessel diseases and the stricture of the main trunk was confirmed in 12.4%. 128 patients underwent only coronary bypass operation, in the others thrombendarterectomy (17 patients), valvular operation (11 patients) and resection of the left ventricular aneurysma (5) were carried out simultaneously. The IMA graft was placed in the majority of the cases on the LAD (70.8%) or as a sequential anastomosis on the LAD-diagonal system (21.1%). The average number of peripheral anastomoses was 2.8 anastomoses patient. 2.5% was the rate of early mortality (4 patients), reoperation was performed in 10 cases because of bleeding or tamponade and perioperative infarction occurred in 8 cases. 3.1% was the rate of late mortality (5 patients). The average follow-up examination time was 12.7 months (3-39 months). At the postoperative examinations 88.8% of the patients were free of angina and 108 patients got into NYHA I state after the operation. Of the 43 control bicycle ergometric examinations 35 were negative and 8 positive.(ABSTRACT TRUNCATED AT 250 WORDS)

Valve surgery combined with myocardial revascularisation. Report of 62 cases.

Combined valvular and coronary bypass surgery was performed in 1984-1988 in 62 patients. Their age range at operation was 38-75 (mean 59) years and more than 90% were in NYHA class III or IV. Valve replacement was performed in 55 cases--mitral in 13, aortic in 33, tricuspid in one and combined valve procedures in eight cases--and valvular correction in seven cases. The patients also received a total of 92 coronary artery grafts (1-4/patient, mostly as single grafts). The hospital mortality was 3% and there were two late deaths. Follow-up was 100% complete 2-52 (mean 22) months after surgery, and more than 90% of the survivors were improved.

Successful surgical repair of a congenital subvalvular left ventricular aneurysm.

Subannular left ventricular aneurysms are rare in white persons. Six white patients have been reported in the literature who underwent surgical repair because of subaortic left ventricular aneurysm. The authors report on a further case, a 41 year-old woman who was operated on at their clinic. The rare occurrence of this disease inspired them to review the literature and to describe their case.

Clinical experience with the Björk-Shiley integral monostrut heart valve prosthesis in the aortic and mitral position.

From May 1982 to May 1985, 174 Björk-Shiley integral monostrut (BSIM) heart valve prostheses were implanted in 160 patients. Eighty-eight valves were placed in mitral and 86 in aortic position. There were 92 males and 78 females with a mean age of 54.1 years (140 patients were in NYHA class III or IV (87.5%]. Single valve replacement was performed in 116 (72%) patients, 30 (19%) underwent multiple valve procedures and in 14 (9%) valve replacement was combined with coronary artery bypass surgery. There were no intraoperative deaths. Six patients died within the first month after surgery. One hundred and fifty-two (98.7%) patients were followed for a total of 190 patient years (average 14.8 months per patient). There were 8 late deaths (4.2 per 100 patient-years), 5 of these were valve related. Valve related complications were observed in 9 patients (4.5 per 100 patient-years). The overall incidence of peripheral embolization was 2.6 per 100 patient years. At the time of the follow-up study 136 (94%) patients were in functional class I and II. Fourteen patients with isolated AVR and six with MVR underwent hemodynamic evaluation on an average of 12 and 10 months after surgery. The early results suggest that the BSIM prosthesis represents a promising alternative in heart valve replacement, because there were no mechanical failures, thromboembolic complications are rare and hemodynamic performance is good.

Gentamycin in cardiac surgery.

Gentamycin concentration in the serum, pericardial fluid, auricle, valve and papillary muscles of 14 patients subjected to cardiac surgery was determined after intramuscular administration of 80 mg of the drug. Fifty to 140 minutes after administration the mean level in the serum was 6.0 mcg/ml, in the pericardial fluid 0.6 mcg/ml, in the auricle 5.8 mcg/g, while after 120 to 240 minutes in the valve 1.2--9.6 mcg/g and in the papillary muscles 2.0--3.6 mcg/g of gentamycin was measured. Consequently, an efficacious gentamycin concentration can be achieved in the cardiac tissues but not in the pericardial fluid which makes gentamycin excellently suited for the prevention and treatment of the infectious complications of heart operations.

An operated case of Holt-Oram syndrome with autosomal dominant inheritance.

This report is concerned with a patient successfully operated for Holt-Oram syndrome. The disorder is inherited dominantly with complete penetrance and variable expressivity. It is pointed out that in cases of congenital heart disease familial cumulation must be borne in mind which can easily be verified by pedigree investigation. After demonstrating autosomal dominant inheritance, suitable inferences must be drawn for genetic counseling. Attention is drawn to the heart-surgical significance of the rhythm disorders so often associated with the syndrome.