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Biomedical subjects

S Saltissi

Publications and source records attributed to S Saltissi.

32 records · Page 2Linked to original sources

Cardiac arrhythmias during acute exacerbations of chronic airflow limitation: effect of fall in plasma potassium concentration induced by nebulised beta 2-agonist therapy.

The effect on cardiac rhythm of the fall in plasma potassium concentration induced by nebulised beta2-agonist therapy was studied in 20 patients admitted to hospital with an acute exacerbation of their reversible chronic airflow limitation. Arrhythmias considered serious or potentially life-threatening were recorded in 13 patients (65%). However, there was no significant increase in these arrhythmias in the hour following administration of nebulised beta2-agonist despite a significant fall in plasma potassium concentration during this period.

Acute Disease↗

Primary cardiac amyloidosis in a young man presenting with angina pectoris.

A 32 year old man presenting with typical angina pectoris was found to have primary cardiac amyloidosis. Myocardial infiltration was strongly suggested by echocardiography, and a histological diagnosis was confirmed by renal biopsy. Nevertheless, technetium pyrophosphate myocardial scanning, recently proposed as a sensitive non-invasive test, showed negative results despite widespread cardiac involvement confirmed at necropsy after unexpected sudden death. Postmortem findings also showed subintimal amyloid material in a severely narrowed right coronary artery. This case highlights several unusual clinical features in a patient with advanced primary cardiac amyloidosis.

Adult↗

The effects of oral digoxin therapy in primary mitral leaflet prolapse.

The effects of oral digoxin on symptoms, arrhythmias, exercise tolerance and echocardiographic function in primary mitral leaflet prolapse were studied in 23 patients using a double-blind crossover protocol. Digoxin reduced the incidence and severity of chest pain compared with both the control (P = 0.0002) and placebo (P = 0.0005) periods. We found a high (83%) incidence of predominantly minor arrhythmias on continuous ambulatory monitoring. Digoxin favourably affected the incidence of frequent supraventricular ectopic beats and supraventricular tachycardia but was associated with a significant number (P less than 0.0025) of asymptomatic bradyarrhythmias. In patients with frequent ventricular ectopics, digoxin had no consistent effect. No difference in exercise tolerance between treatment periods was found on maximal treadmill stress testing, but digoxin administration resulted in an increase in echocardiographic mean circumferential fibre shortening velocity (P less than 0.01) and fractional shortening percent (P less than 0.01). This study demonstrates the efficacy of oral digoxin therapy in ameliorating chest pain in patients with primary mitral leaflet prolapse and suggests a favourable effect on supraventricular arrhythmias in such patients.

Administration, Oral↗

Effect of beta adrenergic blockade on thallium-201 myocardial perfusion imaging.

Nine patients with stable angina (group 1) underwent maximal treadmill stress testing and thallium-201 (201T1) myocardial scintigraphy after intravenous propranolol hydrochloride, and after placebo. Though seven of the nine patients exercised longer after propranolol than after placebo, this difference did not reach statistical significance. Propranolol, however, significantly reduced the mean maximum rate pressure product. Comparison of the perfusion scans on and off propranolol showed that in 36 out of 90 of the myocardial segments recorded (nine patients, five segments scanned twice per patient), only one of the scans showed a defect. In 24 out of 36 of these the propranolol scan was negative, the defect appearing in the placebo scan. Defects present on both scans but differing significantly in size occurred in 22 out of 54 view pairs (nine patients, three views after exercise and three views after redistribution on propranolol and on placebo), and in 19 of these the smaller defect was seen in the propranolol scan. In one of the nine patients, the propranolol scan was normal (false negative), whereas defects corresponding to angiographically proven coronary artery lesions were seen on the placebo scan. Six patients (group 2) were maximally exercised after propranolol and then re-exercised to the same rate pressure product on placebo. Again 16 out of 60 of the segment pairs disagreed and in 10 of these the unmatched defect was present on the placebo scan. In 10 out of 14 discrepant view pairs, the smaller defect occurred on the propranolol scan. Thus in patients taking propranolol, negative results do not exclude coronary artery disease, and perfusion defects (if present) though accurately reflecting the presence of disease may underestimate its true extent.

Adult↗

Effects of early administration of a highly purified hyaluronidase preparation (GL enzyme) on myocardial infarct size.

79 patients with suspected myocardial infarction entered a randomised trial to establish the safety of early intravenous administration of a highly purified hyaluronidase preparation (GL enzyme) and to assess its effects on eventual infarct size as measured by electrocardiographic, enzymatic, and scintigraphic criteria. Of the 71 patients with infarction, 35 received GL enzyme and 36 placebo within 6 h of the onset of chest pain. GL enzyme injected into a peripheral vein produced no adverse changes in the clinical, haemodynamic, biochemical, or haematological variables studied. GL enzyme reduced precordial electrocardiographic indices of infarct size as reflected by a diminution (p less than 0.02) in the degree of both R wave loss and Q wave development. In addition, the number of leads developing pathological Q waves (N delta Q greater than or equal to 2), a sign of progression from ischaemia to necrosis, was reduced (p less than 0.05) after GL enzyme treatment. However, there were no significant differences in infarct size as measured by cumulative creatine kinase MB isoenzyme release or technetium-99m pyrophosphate scintigraphic infarct area, or in clinical outcome during the hospital stay. Interpretation of the enzymatic and scintigraphic data was complicated by chance bias in pre-treatment randomisation which resulted in more (p less than 0.05) patients with severe haemodynamic impairment (and hence probably larger infarct sizes) entering the GL enzyme group. Nonetheless, a favourable effect of GL enzyme on infarct size was demonstrated by precordial electrocardiographic QRS mapping, here each patient acts as his or her own control.

Clinical Trials as Topic↗

Relation of angiographically defined coronary artery disease to plasma lipoprotein subfractions and apolipoproteins.

The relation of coronary artery disease to plasma lipoproteins was examined in 104 men aged 35-65 years undergoing coronary angiography for suspected myocardial ischaemia. A score reflecting the number, degree, and length of stenoses in seven major coronary arteries was assigned to each angiogram. Lipid concentrations in lipoprotein subfractions were measured after preparative ultracentrifugation; plasma apolipoprotein concentrations were measured by electroimmunoassay. Men with high coronary scores tended to have lower plasma high-density lipoprotein (HDL) cholesterol concentrations and higher low-density lipoprotein (density 1.019-1.063 g/ml) cholesterol concentrations than subjects of similar age with low coronary scores (p approximately equal to 0.1). The strongest relation, however, was with the cholesterol concentration in the HDL2 subfraction (density 1.063-1.125 g/ml) of HDL, which averaged 44% lower in the severely affected patients (p less than 0.005). No associations were found between the coronary score and HDL3 cholesterol, the cholesterol content of lipoproteins of density less than 1.019 g/ml, plasma triglyceride, or the concentrations of apolipoproteins AI, AII, and E. The high coronary scores associated with low HDL2 concentrations reflected an increase in the number of both partial and complete stenoses distributed throughout the coronary tree. In contrast the sizes of the lesions and the proportion producing complete occlusion were unrelated to HDL2.

Adult↗

The effects of chronic oral cimetidine therapy on the cardiovascular system in man.

1 The demonstration of histamine (H2) receptors in the cardiovascular system in man and the widespread use of the specific H2 receptor antagonist cimetidine for the treatment of peptic ulcer has necessitated assessment of the cardiovascular effects of this drug during oral therapy in man. 2 Consequently, nineteen patients with a history of peptic ulcer but in symptomatic remission underwent a double-blind crossover trial of oral cimetidine v placebo, each treatment period lasting 4 weeks. No significant difference in various cardiac parameters at rest (heart rate, blood pressure, ECG) or following a maximal treadmill exercise test (time-into-protocol, maximum heart rate and blood pressure) was found between the groups. Similarly, cimetidine produced no change in the incidence of ventricular ectopics or in heart rate on 24 h ambulatory monitoring and had no effect on left ventricular volume or contractility as measured by echocardiography. 3 Thus oral administration of cimetidine in a dose of 400 mg four times daily was associated with no demonstrable cardiovascular changes. In addition, since this dose is thought compatible with cardiovascular H2 receptor blockade this study favours the lack of a physiological role for these receptors in man.

Cardiovascular Diseases↗

Advantages of technetium pyrophosphate scintigraphy over plasma enzyme analysis in estimation of anterior myocardial infarct size.

Infarct size was estimated by cumulative creatine kinase MB isoenzyme (CKMB-r) release and by technetium 99m stannous pyrophosphate (TcPYP) scintigraphy in 27 patients with acute anterior myocardial infarction. In eight patients, scintigraphy showed a central area of reduced tracer uptake surrounded by a peripheral rim of increased TcPYP accumulation ("doughnut" pattern). This appearance occurred only in large infarcts and the maximal scintigraphic area (51.3 +/- 2.8 cm2, mean +/- SEM) in this group was significantly greater than that in the remainder (28.1 +/- 2.5 cm2). Correlation between CKMB-r and maximal scintigraphic infarct area was moderate in the whole group. Exclusion of patients, however, with "doughnut" scintigrams in which correlation was very poor, resulted in substantial improvement in the remainder. It is suggested that in the central regions of large "doughnut" infarcts, reduced blood flow hinders the efflux of CKMB from the centre causing an underestimate of infarct size. Pyrophosphate scintigraphy appears to be more accurate than CKMB release in measuring the size of these large anterior infarcts.

Adult↗

Assessment of prognostic factors in patients undergoing surgery for non-rheumatic mitral regurgitation.

Twenty-four patients who had undegone mitral valve surgery for pure non-rheumatic mitral regurgitation were studied non-invasively six months to six years postoperatively. The long-term results of operation were assessed on the basis of clinical history, echocardiography, and treadmill stress testing using a points scoring system. The score so obtained was used to divide the patients into those with a good response to surgery (group 1) and those responding poorly (group 2). The effects on the long-term surgical outcome of several intraoperative and preoperative factors were then analysed both together and separately. A short symptomatic history (less than 1 year), a normal left ventricular end-diastolic volume index (less than or equal to 100 ml per m2), and a large post-ectopic potentiation of KV max (greater than 50 s-1) were found to be favourable prognostic factors when analysed independently. An angiographic ejection fraction less than 0.5 was uniformly associated with a poor outcome, and 71 per cent of patients in atrial fibrillation at the time of operation also responded badly. In those patients with good long-term function, cold potassium cardioplegia was more commonly used than intermittent aortic cross clamping as the means of intraoperative myocardial preservation, though this difference did not reach conventional significance. A standard analysis of variance allowed assessment of length of history, left ventricular end-diastolic volume index, and type of valve prosthesis simultaneously. This indicated that both length of history and left ventricular end-diastolic volume index were highly significant prognostic factors. The use of a Björk-Shiley as opposed to a Starr-Edwards prosthesis also emerged as significantly favouring a good long-term result. The state of the left ventricular myocardium before operation and the type of valve prosthesis used were thus shown to be the prime determinants of surgical outcome in these patients. The optimum time for operation was shown to be within one year of the onset of symptoms, and before the left left ventricular end-diastolic volume index exceeds 100 ml per m2, or the ejection fraction falls to less than 0.5. At such a time, irreversible changes in myocardial function sufficient to negate the beneficial effects of mitral valve surgery have not yet occurred.

Angiocardiography↗

Ambulatory ECG monitoring.

The development and widespread application of 24-hour ambulatory ECG monitoring in the last 15 years represent major advances in cardiology. It is the most sensitive method of detecting arrhythmias and allows objective evaluation of such abnormalities and their response to treatment as the patient continues the activities of daily life. Information on prognosis and early diagnosis in patients with coronary artery disease has been obtained but more data and a greater understanding of their relevance in normal populations are necessary. Until then the significance of the findings in many situations, especially in asymptomatic patients, will remain speculative and decisions on whether or not to institute therapy will continue to be somewhat arbitrary.

Anti-Arrhythmia Agents↗