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Biomedical subjects

H F Weich

Publications and source records attributed to H F Weich.

29 records · Page 2Linked to original sources

Late symptomatic exercise-induced coronary vasospasm after percutaneous transluminal coronary angioplasty. A case report and review.

A patient who underwent a successful double-vessel percutaneous transluminal coronary angioplasty (PTCA) had suffered from exercise-induced ST-segment elevation associated with angina pectoris (AP). This ECG pattern was present both before and 12 months after PTCA while nifedipine (Adalat; Bayer-Miles) therapy was electively discontinued. Reintroduction of calcium blockade with this drug eliminated the chest pain and resulted in normalization of the stress ECG. Cardiac catheterization at 6 and 12 months after PTCA demonstrated continuing angiographic improvement of the coronary stenoses of the left anterior descending and left circumflex (LCx) coronary arteries previously subjected to PTCA. It is believed that coronary artery spasm at the PTCA site on the LCx coronary artery was responsible for the AP and exercise-induced ST-segment elevation. Likely pathogenetic mechanisms of coronary vasospasm during and after the performance of PTCA, as well as the interrelationship with re-stenosis and the clinical implications of drug therapy, are discussed.

Angina Pectoris↗

[The effect of heparin induced increase of free plasma thyroxine on cardiac rhythm after myocardial infarction].

It is well known that an acute myocardial infarction is accompanied by a rise in levels of plasma free fatty acids (FFA), which may lead to a subsequent increase in cardiac arrhythmias. Administration of heparin to patients after an acute myocardial infarction gives rise to an increase both in plasma FFA levels and plasma free thyroxine levels. If administered without a fatty meal the rise in FFA is not accompanied by an increase in arrhythmias. The effect of the heparin-induced rise in plasma free thyroxine on cardiac rhythm has never been investigated. The aim of the present study was to investigate a possible arrhythmic effect of a heparin induced increase in plasma free thyroxine in a group of patients with acute myocardial infarction. We were able to confirm a significant heparin-induced rise in plasma free thyroxine levels, as measured by the effective thyroxine ratio. Although a slightly significant increase in ventricular premature beats could be demonstrated after heparin administration when using the Wilcoxon rank sum test for statistical analysis (but not when the paired t-test was utilized), no significant correlation with free thyroxine levels could be found. Heparin administration to patients suffering from myocardial infarction seems to be safe in terms of a possible arrhythmic effect.

Aged↗

Acute coronary thrombus formation after stress testing following percutaneous transluminal coronary angioplasty. A case report.

Successful percutaneous transluminal coronary angioplasty (PTCA) was performed on a 37-year-old white man with an isolated 95% right coronary artery stenosis who initially presented with type II unstable angina. Submaximal treadmill stress testing was not carried out before PTCA, but testing 3 days after PTCA was strongly positive without accompanying symptoms of myocardial ischaemia. Some 30 minutes after this test the patient experienced severe precordial pain with features of a hyperacute transmural inferior myocardial infarction. Immediate coronary arteriography delineated fresh thrombus related to the previous PTCA site. Intracoronary thrombolysis with streptokinase was successful, revealing an underlying severe stenosis at the PTCA site. PTCA was not repeated, nor was emergency coronary artery bypass grafting (CABG) performed. This is the second such case documented in the literature; the first patient failed to respond to intracoronary thrombolysis with streptokinase and was submitted to emergency CABG. The possible underlying pathophysiological mechanisms are discussed. We believe that the late thrombus formation was directly related to submaximal stress testing after successful PTCA, and recommend that testing to assess the efficacy of PTCA be deferred until at least 1 month after the procedure to allow for completion of the healing process.

Acute Disease↗

Pre-operative assessment of cardiac patients for non-cardiac surgery.

Non-cardiac surgery presents significant risks to patients with cardiac diseases. With the improvement in anaesthetic techniques and intensive care facilities, many cardiac patients who in the past would have been considered as being at too great a risk are now being considered for non-cardiac surgery. Smaller centres must still practise strict selection of patients if they do not possess an intensive care unit with facilities for full haemodynamic monitoring. We present a review of the recent literature and current practice at our hospital to assist clinicians in assessing these patients for anaesthesia. However, the final decision whether the patient is fit for anaesthesia still rests with the anaesthetist.

Anesthesia↗

The prevalence of ischaemic heart disease in three rural South African communities.

In a population reportedly excessively prone to ischaemic heart disease (IHD) i.e. South African (SA) whites, a 3-community study of 7188 subjects aged 15-64 showed a high prevalence of chest pain by questionnaire (9.5% of males, 7.7% of females) or by ECG findings suggestive of IHD (12.8% males, 6.7% females). In the oldest decile (55-64 years) the prevalence of chest pain and/or ECG findings was 33.4% of males and 26.1% of females. For all ages, 18.4% of males and 13.1% of females were apparently affected. Though females were as likely as males to have a history of chest pain they had fewer ECG findings suggestive of IHD and the history was less likely to have been confirmed by a doctor. The significance of individual findings, assessed by the strength of their associations with symptomatic history and age, appeared to differ between the sexes; though very common, medium S-T depression was not classed as suggestive of IHD in females, while left ventricular hypertrophy was unimpressive in males. Large and medium Q waves, large S-T depression, large and medium T wave inversion were positive in both sexes, but left and right bundle branch block only in males. There was little overlap between a history of chest pain and suggestive ECG findings; however, a previous diagnosis of IHD by the family doctor increased the overlap by up to 6 times.

Adolescent↗

[Aortocoronary bypass surgery at Tygerberg Hospital, 1978 - 1980].

Between January 1978 and December 1980. 118 patients underwent saphenous vein bypass surgery for obstructive coronary artery disease at Tygerberg Hospital. Sixteen patients in addition to bypass surgery underwent mitral and/or aortic valve replacement or resection of a ventricular aneurysm. The operative and hospital mortality was 3,0% (4/134) for all patients and 3,3% (4/118) for patients who had aortocoronary bypass surgery as the sole procedure. Follow-up of the surviving patients for a mean period of 16,4 months revealed a low incidence of late myocardial infarction of 3.6% (4/112) resulting in the death of only 1 patient; 89.1% of patients were free of angina pectoris and the majority of these resumed their normal work or enjoyed their retirement.

Coronary Artery Bypass↗

Two simple inexpensive photographic methods for viewing ECG-gated radionuclide blood pool images.

Although the ECG-gated radionuclide blood pool scan (GBPS) has become an established method for studying regional myocardial wall motion, it is usually performed with the aid of an expensive computer system. A simple, inexpensive method was developed to view gated radionuclide blood images by a film loop and a photographic motion detection (PHOMOT) technique. These techniques were compared with left ventricular cine angiography in 15 patients. Segmental wall movement (78 segments) showed identical results in 92% of cases. In all patients the same diagnosis was arrived at by GBPS and cine angiography. The photographic techniques developed offer a simple screening procedure to reduce cardiac catheterization in patients with suspected abnormalities of left ventricular wall contraction.

Cineangiography↗

The extraction of thallium-201 by the myocardium.

The concentration of thallium-201 in the myocardium immediately following injection of tracer is the result of both blood flow delivering tracer to the heart and extraction by the myocardium. In these studies, the extraction of thallium-201 by the canine myocardium was determined as a function of heart rate, coronary blood flow, hypoxia, changes in pH, and following administration of propranolol, insulin, and strophanthin. Under basal conditions, extraction fraction measured 88 +/- 2.1%, following pacing to a rate of 195 beats/min extraction fraction remained unchanged at 88.5%. Similar results were found with changes in pH, propranolol, insulin, and strophanthin. Hypoxia caused a significant decrease in extraction fraction to 77.9%. When coronary blood flow was increased in excess of demands by drugs, extraction fraction fell logarithmically.

Acidosis↗

[Ventricular aneurysmectomy and infarctectomy].

During a 22-month period, April 1972 to February 1974, 4 patients underwent ventricular aneurysmectomy at the Karl Bremer and Tygerberg Hospitals for congestive cardiac failure. In addition, 1 patient with an aneurysm and 3 patients with acute myocardial infarcts, ranging from 16 to 28 days postinfarction, underwent emergency surgery for recurrent malignant arrhythmias. The preoperative treatment, cardiac catheterisation data and surgical findings are outlined. The over-all survival rate is 75% for a mean follow-up period of 12,5 months (range 8-22 months). It is concluded that aneurysmectomy, for congestive cardiac failure, and infarctectomy, for life-threatening ventricular arrhythmias, are gratifying and worthwhile procedures.

Acute Disease↗