Heart

Muir, A L

doi: 10.1136/hrt.58.1.1pmid: 3304369

Billingham, M

doi: 10.1136/hrt.58.1.6pmid: 3620244

Yousif, H; Davies, G; Westaby, S; Prendiville, O F; Sapsford, R N; Oakley, C M

doi: 10.1136/hrt.58.1.9pmid: 3304371

One hundred consecutive patients undergoing coronary artery bypass surgery were randomly allocated to a preoperative (24 h) intravenous infusion of isosorbide dinitrate (1.5-15 mg/hr) (50 patients) or to placebo (50 patients). The characteristics of the two groups were similar. Evidence of acute myocardial ischaemia was sought by continuous electrocardiographic Holter recordings and acute myocardial infarction by the appearance of new Q waves and increased activity of the creatine kinase MB isoenzyme. Episodes of acute myocardial ischaemia were found in 18% of patients in the control group and in none of those who received isosorbide dinitrate. None the less, the frequency of perioperative myocardial infarction was similar (22% and 18% respectively) in the two groups. Perioperative infarction was significantly more common in women, in patients with unstable angina or poor left ventricular function, in those who had coronary endarterectomy, and in those in whom the aortic clamping time was greater than 50 minutes. These factors may have obscured any effect that prevention of preoperative ischaemia had on perioperative infarction. Preoperative infusion of isosorbide dinitrate eliminated preoperative ischaemia but did not influence the occurrence of perioperative infarction. The probable benefits of prevention of preoperative ischaemia on postoperative left ventricular function, which is a determinant of long term survival, remain to be established.

Machado, M V; Chita, S C; Allan, L D

doi: 10.1136/hrt.58.1.15pmid: 3620237

The time to peak velocity was measured by Doppler echocardiography in the pulmonary artery in 102 normal human fetuses (gestational age 16-30 weeks). Time to peak velocity in the aorta was measured in 72. In 58 both measurements could be made in the same fetus. The time to peak velocity was shorter in the pulmonary artery than in the aorta. This difference was statistically significant. This suggests that in the midtrimester fetus mean pressure in the pulmonary artery is higher than in the aorta.

Fukazawa, M; Honda, S; Fukushige, J; Sunagawa, H; Yasui, H; Ueda, K

doi: 10.1136/hrt.58.1.19pmid: 3620238

A simplified model based on Gorlin's formula was used to derive an index of the cross sectional area of ventricular septal defects from commonly used cardiac catheterisation data. This index was compared with the area of the defect measured during operation and expressed as a ratio to the cross sectional area of the aorta. The highly significant linear relation (r = 0.94) between this index of the defect area and the size of the defect measured at operation means that the severity of a ventricular septal defect can be assessed from haemodynamic data obtained at cardiac catheterisation.

Singer, D R; Dean, J W; Buckley, M G; Sagnella, G A; MacGregor, G A

doi: 10.1136/hrt.58.1.24pmid: 2956978

Plasma concentrations of atrial natriuretic peptide were measured in eight patients undergoing elective cardiac catheterisation and angiography. All patients had normal resting pressures in the cardiac chambers and no clinical evidence of heart failure. Plasma atrial natriuretic peptide rose significantly from the superior vena cava into the right atrium and right ventricle. The increase into the right atrium was variable, with no increase in three subjects, but there was a consistent increase in all subjects from the superior vena cava to to the right ventricle. These findings in the right atrium are probably caused by inadequate mixing and streaming of blood from the coronary sinus containing high concentrations of atrial natriuretic peptide. There was no increase in the concentration of natriuretic peptide from the pulmonary artery to the left ventricle, but the concentrations in the left ventricle were significantly higher than in the superior vena cava. These findings demonstrate that the heart secretes atrial natriuretic peptides in the absence of cardiac failure. Studies based on sampling of the right atrium will not accurately measure cardiac secretion of atrial natriuretic peptide and will therefore be likely to obscure the mechanisms responsible for regulating its secretion. The right ventricle and pulmonary artery are the best sampling sites to measure atrial natriuretic peptide release from the right atrium.

Nomura, M; Kato, K; Nagasaka, A; Shiga, Y; Miyagi, Y; Fukui, R; Nakano, H; Abo, Y; Okajima, S; Nakai, A

doi: 10.1136/hrt.58.1.29pmid: 3620239

The enzyme beta-enolase (alpha beta and beta beta forms) is present in skeletal and heart muscle and catalyses the glycolysis of 2-phosphoglycerate to phosphoenolpyruvate. The enzyme was measured in serum samples from patients with acute myocardial infarction, angina pectoris, congestive heart failure, and idiopathic cardiomyopathy. Serum concentrations of beta-enolase were significantly increased in acute myocardial infarction but not in the other cardiovascular diseases. Activity peaked approximately 12 to 14 hours after an acute attack of chest pain, and then gradually decreased as the patient recovered. The rise and fall in beta-enolase concentration were faster and steeper than those of creatine kinase activity, particularly in patients in whom activities of both these enzymes were less high. The assay of beta-enolase, which is highly specific and sensitive, has considerable advantages for the early diagnosis of myocardial infarction and the diagnosis of a second episode of myocardial infarction because beta-enolase concentration increases very early and rapidly and clears quickly. These data imply that serum beta-enolase may be a more effective marker for early myocardial infarction, particularly in milder cases, than measurement of creatine kinase activity.

Boon, N A; Frew, A J; Johnston, J A; Cobbe, S M

doi: 10.1136/hrt.58.1.34pmid: 3304370

Fifteen patients with dual chamber pacemakers implanted for atrioventricular block (11) or sinoatrial disease (4) completed a single blind within-patient comparison of symptoms and 24 hour intra-arterial blood pressure during long term atrioventricular synchronous (DDD) pacing and long term ventricular demand (VVI) pacing. The patients reported significantly less breathlessness, fatigue, and dizziness and a significantly greater sense of general well-being during DDD pacing than during VVI pacing. Twelve of the fifteen patients expressed a strong preference for DDD pacing. Systolic blood pressure tended to be lower and was significantly more variable during VVI pacing than during DDD pacing (mean (SD) daytime systolic blood pressure 132.4 (17.1) and 140.4 (13.1) mm Hg respectively). Accordingly, episodes of hypotension were more common during VVI pacing, which may partly explain why the patients reported more symptoms during this mode of pacing.

Sullivan, I D; Presbitero, P; Gooch, V M; Aruta, E; Deanfield, J E

doi: 10.1136/hrt.58.1.40pmid: 3620240

Ventricular arrhythmia is common after repair of tetralogy of Fallot. Such arrhythmia could be caused by damage at surgical repair or it could be part of the course of the disease. Fifty patients, 32 aged 1-7 years and 18 aged 13-43 years at surgical repair, underwent 24 hour electrocardiographic monitoring before and 2-75 (mean 44) months after repair. Before operation none of the younger group had appreciable ventricular arrhythmia, whereas ventricular arrhythmia was already present in eight (45%) of 18 patients in the older group. At follow up ventricular arrhythmia was present in four patients from the younger group and seven from the older group. Three of these four younger patients had had insertion of a conduit from the right ventricle to the pulmonary artery or reoperation. Six of the seven older patients had had appreciable ventricular arrhythmia before operation. New ventricular arrhythmia developed in only two (5%) of the 43 patients who had uncomplicated repair of tetralogy of Fallot. Thus the high frequency of ventricular arrhythmia after repair of tetralogy of Fallot cannot be attributed to the effect of operation alone because in the majority of patients it was already present before operation. Preoperative ventricular arrhythmia occurred almost exclusively in older patients; this suggests that early surgery may reduce the occurrence of this late complication.

Erbel, R; Börner, N; Steller, D; Brunier, J; Thelen, M; Pfeiffer, C; Mohr-Kahaly, S; Iversen, S; Oelert, H; Meyer, J

doi: 10.1136/hrt.58.1.45pmid: 3620241

The diagnostic value of a combination of transoesophageal and transthoracic echocardiography was evaluated in 21 patients with dissection of the aorta. The results were compared with those of computed tomography, aortography, and with findings at operation or necropsy or both. Transthoracic echocardiography identified three of the four patients with type I dissection, two of the five patients with type II dissection, and one of the 12 patients with type III dissection. When transoesophageal echocardiography was used as well the degree of aortic dissection was identified correctly in all 21 patients. In one patient with type I and in eight patients with type III dissection spontaneous echocardiographic contrast with a mural thrombus within the false lumen could be detected. Computed tomography was unable to demonstrate an intimal flap in one of two patients studied with type I dissection, in two of three patients with type II dissection, and in one of nine patients with type III dissection. Aortography was negative in one of two patients studied with type I dissection, two of four patients with type II dissection, and in one of eight patients with type II dissection. The whole thoracic aorta can be imaged by a combination of transthoracic and transoesophageal echocardiography. The addition of transoesophageal echocardiography to transthoracic echocardiography improves the recognition of aortic dissection. Furthermore, this examination can be performed at the bedside and the findings can be used as a basis for treatment.