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Biomedical subjects

M H Frick

Publications and source records attributed to M H Frick.

17 recordsLinked to original sources

Survival with total occlusion of the left main coronary artery. Significance of the collateral circulation.

Four patients with total occlusion of the left main coronary artery are described. Angina pectoris was severe (NYHA class 3--4) and had lasted 20 months to seven years. Three patients had experienced a myocardial infarction. All displayed large collaterals arising from a nearly normal right coronary artery and feeding both the left anterior descending and the left circumflex arteries. The left ventricular ejection fractions ranged from 20% to 65%, and all patients had varying degrees of left ventricular asynergy. Coronary artery bypass surgery resulted in a marked improvement in three patients; one patient who underwent an aneurysmectomy died two months after the operation. The data show that total occlusion of the left main coronary artery is compatible with survival if adequate collateral supply develops from the right coronary artery. In this rare angiographic subset collateral circulation is clearly functionally significant.

Adult

Persistence of improved exercise tolerance and degree of revascularization after coronary bypass surgery. A prospective randomized study.

Exercise tolerance was repeatedly determined over a 2-year period in a series of 100 patients with coronary heart disease randomly allocated for medical therapy and coronary bypass surgery. The surgical group had a consistently better exercise tolerance than the medical group during the whole follow-up. Completeness of the revascularization, assessed by repeated graft and native vessel angiography, resulted in a marked improvement whereas incompletely revascularized patients exhibited only a marginal improvement which, nevertheless, to some degree exceeded the result of medical management alone. It is concluded that coronary bypass surgery and medical therapy, when indicated, result in markedly better exercise tolerance than medical management alone. This improvement persists up two years after the operation and is largely dependent on the completeness of the revascularization.

Adrenergic beta-Antagonists

Work status after coronary bypass surgery. A prospective randomized study with ergometric and angiographic correlations.

The rate of return to work was assessed in a series of patients with coronary heart disease randomly allocated to medical and surgical treatment groups of 50 patients each. Sixteen of the medical and 19 of the surgical patients were already retired at entry and did not resume work later. Only 9 patients (26%) on medical therapy were working at 2-year follow-up in contrast to 18 (60%) working after bypass surgery (p less than 0.05). Functional classification of angina pectoris and exercise tolerance on ergometry were significantly better in the surgical group, especially in the surgical subgroup at work. Repeated postoperative anigographies of the inserted grafts and native vessels disclossed that completeness of revascularization was related to work status after bypass surgery. The data suggest that a combination of coronary bypass surgery and medical therapy, when indicated, is superior to medical therapy alone in influencing the rate of working in coronary heart disease.

Adult

A new electrical equipment for handgrip testing.

Devices available for isometric handgrip testing revealed constructional deficiences likely to give rise to inaccurate data. A new electrical device was constructed which eliminates the defects in earlier designs. The new equipment consists of a U-shaped handgrip transducer, a measuring device, and a slave monitor for the patients. The patient's maximum handgrip force is determined as a peak voltage, which is stored in analog form. Two comparators help to set the desired handgrip force during the actual testing. The slave monitor's two lamps and analog meter help the patient to apply a force which is maintained at a selected percentage of the maximum force. The device has been shown to operate well in a longitudinal study of drug treatment of hypertension.

Electrodiagnosis

Serum lipids in angiographically assessed coronary atherosclerosis.

Cholesterol, triglycerides, and Lp(a)/pre-beta1 lipoprotein were analyzed in 153 patients typed for liproprotien patterns. Coronary atherosclerosis was determined by selective coronary angiography and graded by a system taking into account proximal, middle and distal segments. Smoking habits, family history and hypertension were also recorded. Normal coronary arteries were encountered in 45, moderate coronary atherosclerosis (less than median score) in 50, and severe changes (greater than median score) in 58 patients. Cholesterol (P less than 0.05), positivity of Lp (a)/pre-beta1 lipoprotein (P less than 0.01), a family history of coronary heart disease (P less than 0.05), and smoking (P less than 0.01) differed between the group of normal arteries and the whole group of luminal obstructions. Serum triglycerides were not associated with coronary atherosclerosis. Cholesterol, positivity of the Lp(a)/pre-beta1 lipoprotein and a family history of coronary heart disease were also associated with the severity of the disease. Smoking was less prevalent in the group with severe changes.

Adolescent

Penbutolol, a new non-selective beta-adrenergic blocking compound in the treatment of hypertension. A comparision with propranolol.

The antihypertensive effect of a new non-selective beta-adrenergic blocking compound, penbutolol (40 mg b.i.d.), was compared with propranolol (160 mg b.i.d.) in a series of 20 hypertensive patients using a double-blind cross-over scheme. Both compounds reduced both the supine and the standing blood pressure significantly. The magnitude of the responses did not differ significantly and both compounds evoked a commensurate decrease in heart rate. No significant side-effects were noted and a series of laboratory tests did not disclose any biochemical changes.

Adrenergic beta-Antagonists

Response of left ventricular myocardial perfusion and cavity size to beta-blockade by acebutolol.

The effect of beta-blockade by acebutolol on global and regional myocardial perfusion (133Xenon wash-out) was studied in 10 patients with coronary artery disease. Another group of 10 similar patients was used to study the effect of acebutolol on left ventricular cavity size (metal markers--spot film camera). Global perfusion responses roughly paralleled the changes in rate-pressure variable which decreased in 8 patients and increased in 2 who had spontaneous angina pectoris. Regional perfusion decreased more in areas distal to less than 75% stenoses than in those distal to less than 75% stenoses (29 vs 12%; p = 0.10 less than 0.20). Left ventricular asynergy did not modify the response, nor did the presence or absence of collateral vessels. No evidence was found to support the thesis that beta-blockade may evoke a redistribution in perfusion which favours the potentially ischaemic areas of myocardium. Left ventricular cavity size remained unchanged after acebutolol, a cardioselective beta-blocking compound with some degree of agonist activity.

Acebutolol

Coronary bypass surgery. An overview.

During the ten year history of coronary bypass surgery the initially unacceptable high operative mortality has dropped to 1--2%. Of the twin targets of the procedure, alleviation of disabling angina and improvement in the prognosis, the former seems to have been achieved and is universally accepted. Several series with repeated exercise tests show that about 70% of the patients gain definite benefit; a high proportion of these patients become entirely asymptomatic. Reestablishment of effective coronary perfusion via the grafts seems to be the key factor in this response. However, several other factors, such as perioperative infarction, psychogenic effects, cardiac denervation, and changes in left ventricular function, are also involved. There is still disagreement about the effect of bypass surgery on life expectancy. It is not, in fact, known with certainty whether prognosis is improved, although coronary bypass surgery does not appear to be inferior to medical management in terms of prolonging life span. It has also been established that there is an improvement in prognosis after bypass surgery for patients with obstruction of the left main coronary artery, while the fairy favourable prognosis of patients with single vessel disease can hardly be improved. Available data from randomized series consisting of the whole range of patients with coronary heart disease are either quantitatively or qualitatively insufficient by present standards. Accordingly, new data will eventually afford the evidence needed for drawing firm conclusions about the final value of coronary bypass surgery in improving the prognosis of coronary heart disease.

Angina Pectoris

Genetic variation in serum low density lipoproteins and lipid levels in man.

Combined data from 10 different populations indicate that the serum cholesterol and triglyceride levels are higher in Ag(x-) than in Ag(x+) individuals. Although the differences were relatively small, they became more pronounced with increasing age. The Ag(x) antigen, which is associated with the serum low density lipoprotein, is genetically controlled and the present study therefore has revealed a small but significant effect of a single autosomal locus on lipids implicated in the pathogenesis of atherosclerosis. No explanation of the higher cholesterol and triglyceride levels in Ag(x-) than in Ag(x+) persons is apparent.

Age Factors

Lp(a) lipoprotein/pre-beta1-lipoprotein, serum lipids and atherosclerotic disease.

With appropriate electrophoretic techniques and fresh serum samples, the Lp(a) lipoprotein/pre-beta1-lipoprotein is demonstrable as a distinct zone in the area between beta-lipoprotein and ordinary pre-beta-lipoprotein, when sera which are strongly positive with respect to the Lp(a) antigen are analyzed. The Lp(a) lipoprotein is a genetically determined normal serum component. The phenotype Lp(a+) was found significantly more frequently in two series of patients with coronary heart disease (CHD) than in appropriate controls. The frequency difference between patients and controls was particularly pronounced for the Finnish samples studied, 55% of the patients having the phenotype Lp(a+), as opposed to only 31% of the healthy controls. As judged from electrophoresis strips, hibh concentrations of Lp(a) lipoprotein/pre-beta1-lipoprotein were positively correlated with coronary score as determined by angiography. This correlation was highly significant. Total serum cholesterol value was slightly higher in Lp(a+) than in Lp(a-) persons from two of the four population samples studied, but no statistically significant difference was found. Serum triglyceride levels exhibited a statistically insignificant trend towards higher values in Lp(a-) than in Lp(a+) individuals, in three of the four samples tested. The strong association between the phenotype Lp(a+) and CHD, as well as the correlation between high amounts of Lp(a) lipoprotein/pre-beta1-lipoprotein and coronary score on one hand, and the weak correlation between presence of Lp(a) lipoprotein/pre-beta1-lipoprotein and lipid values on the other, make it highly unlikely that the increased frequency of the Lp(a+) phenotype in CHD patients merely reflects an over-all increase of the intravascular pool of LDL and/or VLDL reflected in increased serum levels of cholesterol and/or triglycerides. By the same token, it is unlikely that the insignificant effect on lipid values can, on its own, explain the correlation between Lp(a) phenotype and CHD.

Adolescent

An appraisal of symptom relief after coronary bypass grafting.

Subjective symptomatic improvement is experienced by 90% of patients after coronary bypass surgery. Objective exercise testing reduces this incidence to 70%. An analysis of the multifactorial genesis of pain relief based on data of non-randomized trials reveals that graft patency plays a dominant but not unique role in causing improved symptomatology. In a number of cases, intra-operative myocardial infarctions seem to explain the pain relief but may also have opposite effects. Changes in left ventricular function operate bidirectionally but data on this variable in relation to changes in symptomatology are not amenable for detailed analysis. Progression in native vessel lesions apparently opposes pain relief and has its greatest impact in connection with graft closure. Residual post-operative angina is evidently related also to incomplete revascularization.

Angina Pectoris

Further studies of Lp(a) lipoprotein/pre- beta1-lipoprotein in patients with coronary heart disease.

The present study of 100 patients (46 of whom were included in a previous study) with suspected or proven coronary heart disease (CHD) confirms that Lp(a) lipoprotein and pre-beta1-lipoprotein are closely related, if not identical, and that Lp(a) lipoprotein/pre-beta-lipoprotein occurs more frequently in patients with CHD than in healthy people. Analysis of this lipoprotein component may have predictive value with respect to CHD.

Adult