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Biomedical subjects

V F Huckell

Publications and source records attributed to V F Huckell.

33 records · Page 2Linked to original sources
PubMed1982

Electrocardiographic abnormalities associated with malignant hyperthermia susceptibility.

Serial ECG's were reviewed in 93 consecutive patients who were proven to be susceptible to malignant hyperthermia by caffeine contracture and ATP depletion tests on skeletal muscle biopsies, but who were without a history of pyrexic crises. There were 46 males and 47 females with a mean age of 33 years. Abnormal ECG's were found in 26 of the patients, with conduction defects in 14, repolarization abnormalities (non-specific ST-T changes) or "Q" waves in nine and increased voltages suggesting left ventricular hypertrophy in three (in the absence of hypertension). An abnormal ECG in a young patient may reflect malignant hyperthermia susceptibility.

Adult↗
PubMed1982

Leaking Glenn anastomosis demonstrated by first pass radionuclide angiography.

First pass radionuclide angiography was used to demonstrate a leaking Glenn anastomosis at the superior vena cava--right atrial junction as well as tricuspid atresia and a ligated persistent left superior vena cava. First pass radionuclide angiography may demonstrate anatomic configurations not obvious at cardiac catheterization and can be useful for adults with complicated congenital heart disease, particularly when biplane or multiple view angiography is not possible. Lung perfusion imaging can lead to an incorrect diagnosis of pulmonary embolism if the presence of a Glenn anastomosis in not known.

Adult↗
PubMed1981

Prinzmetal's angina with documented coronary artery spasm. Treatment and follow-up.

Eighteen patients with Prinzmetal's angina were studied angiographically and 17 were followed for an average of 27 months. The were 12 men and six women, with a mean age of 46.3 years. The mean duration of symptoms before clinical diagnosis was 4.1 weeks. Four had had a previous myocardial infarction. Six patients had spontaneous cardiac arrests within 48 hours of diagnosis and hospital admission. At coronary arteriography, 10 patients had significant coronary artery disease; two of these had coronary artery spasm. The remaining eight patients had normal cornary arteries with significant coronary artery spasm at arteriography. Angiographic mitral valve prolapse was found in eight patients; seven of these had inferior ST segment elevation with pain. Six of the 10 patients with significant coronary artery disease had aortocoronary bypasses performed with good results. Ten of the remaining 11 patients who were treated medically had their symptoms controlled with oral isosorbide dinitrate alone or in combination with propranolol, nifedipine or perhexiline but propranolol may have an adverse effect. Though the initial clinical course in untreated patients was unfavourable, progress after starting treatment was good, with no further cardiac arrests, myocardial infarctions, or deaths.

Angina Pectoris↗
PubMed1981

Experience with ergonovine provocative testing for coronary arterial spasm.

We reviewed our experience with the ergonovine provocative test for coronary arterial spasm in 40 patients with pain in the chest believed to be angina pectoris and in one patient with a myocardial infarction and normal coronary arteries. Twenty-nine patients had normal coronary arteries, while 12 had mild to moderate lesions. Ergonovine maleate was administered incrementally in total cumulative doses of 0.25 mg to 1.2 mg. The effect of ergonovine on coronary arterial caliber was determined by comparing the arterial diameter from the angiogram obtained after administration of ergonovine with that from the control. Measurements were made at the same preselected points in both films and also at points of greatest response. Excluding the three cases with complete occlusion, the mean reduction in coronary arterial diameter at preselected points was 12 +/- 15 percent. When the points of greatest response were examined, the maximum reduction in coronary arterial diameter was less than 25 percent in 13 patients, 25 to 50 percent in 20 patients, and more than 50 percent in eight patients. The patterns of response included complete occlusion of a vessel in the three patients with variant angina, diffuse narrowing in 16, diffuse and focal narrowing in six, and spasm at the catheter tip in three patients. All patients with maximum reductions of more than 50 percent in coronary arterial diameter and six of those with maximum reductions of 25 to 50 percent had pain in the chest, but only the three with complete occlusion had associated changes in the S-T segment. Thus, the response in patients with variant angina represents one end of a spectrum of responses to administration of ergonovine. In addition, a large number of patients may have ergonovine-induced pain in the chest without electrocardiographic changes and only an intermediate degree of coronary arterial spasm.

Adult↗
PubMed1980

Malignant hyperthermia susceptibility. A light and electron microscopic study of endomyocardial biopsy specimens from nine patients.

Cardiomyopathy develops in some individuals who have a susceptibility to malignant hyperthermia. We studied right ventricular endomyocardial biopsy specimens from nine patients defined as having this disorder because of positive caffeine contracture tests on skeletal muscle biopsy specimens. Three patients had clinical evidence of cardiomyopathy and six did not. Light microscopy showed cytoplasmic contraction bands, perinuclear clearing, and a mild to moderate variation in myocyte and nuclear size. Ultrastructurally cytoplasmic contraction bands were associated with cardiac villi, myofiberlysis, and myofibrillolysis. These changes and occasional breaks in the sarcolemma were regarded as artefacts of the biopsy procedure. Megamitochondriosis with accompanying degenerative changes in the mitochondria were also seen and probably indicate increased cell metabolism; vacuolation of the cytoplasm was regarded as an "aging" phenomenon. Thus, the biopsy specimens were abnormal, but the changes were artefactual or nonspecific and were not unique to this group of patients. Biopsy did not provide a morphological explanation for abnormal cardiac function.

Adolescent↗
PubMed1980

Aortocoronary bypass in patients with severe left ventricular dysfunction.

The results of aortocoronary bypass grafting in 29 patients with severe left ventricular dysfunction (ejection fraction less than 35%) were studied. All patients had severe angina pectoris; 17 patients has class IV heart function and 12 had class III function according to the New York Heart Association classification. Intra-aortic balloon pump support was instituted preoperatively in all patients. Three patients died in the perioperative period. Survivors were followed up for a mean period of 20 months; there were three late deaths. Sixteen patients were clinically improved; 8 had class I and 8 class II heart function at follow-up. Fourteen patients underwent cardiac catheterization postoperatively at a mean time of 19 months. Although 22 (79%) of the 28 grafts were patent, there was no significant improvement in resting left ventricular dysfunction as assessed by ejection fraction, left ventricular volume or left ventricular end-diastolic pressure. Furthermore, graft patency could not be correlated with improvement in segmental wall motion. There was a 10% operative and an 11.5% late mortality and no measurable improvement in resting left ventricular function in this study but the majority (73%) of the surviving patients experienced definite clinical improvement.

Angina Pectoris↗
PubMed1978

Technetium-99m stannous pyrophosphate scintigraphy in patients with calcification within the cardiac silhouette.

Technetium-99m stannous pyrophosphate scintiscanning was performed in 22 patients with radiographically detected calcification within the cardiac silhouette. All but one of these scintigrams showed a localised area of increased activity similar to that ordinarily seen in acute myocardial infarction. Scintiscans in 3 patients after removal of the calcified aortic valve reverted to negative. It was concluded that this technique for acute infarct detection may yield false positive results in the presence of cardiac calcification.

Calcinosis↗
PubMed1978

Cardiac manifestations of malignant hyperthermia susceptibility.

Malignant hyperthermia is a disease resulting from defective cellular membranes, usually presenting as drug-induced pyrexic crises. We describe four patients with life threatening ventricular arrhythmias or chest pain in the absence of pyrexic crises. Three presented with life threatening arrhythmias and the fourth with severe atypical chest pain. Two patients had a family history of multiple sudden deaths. Resting CKs were elevated in three patients while CK-MB was elevated in one. Resting ECGs were abnormal in three. Three patients had recurrent ventricular tachycardia, two had recurrent ventricular fibrillation and multiple cardiac arrests. Cardiac catheterization showed abnormal left ventricular wall motion in two and minimal mitral valve prolapse in one while all had normal coronary arteries. Thallium-201 myocardial imaging demonstrated large perfusion defects in the patient with electrocardiographic Q waves and normal coronary arteries. Myocardial involvement has been demonstrated by clinical, electrocardiographic, hemodynamic, angiographic and myocardial imaging abnormalities. Malignant arrhythmias occurred in these patients in the absence of pyrexic crises or drug admininstration. Abnormal calcium release in the myocardium, as documented in skeletal muscle membranes, may be a unifying concept for the various manifestations described.

Adult↗
PubMed1977

Basement membranes of small cardiac vessels in patients with diabetes and myxoedema: preliminary observations.

Ultrastructural observations on the basement membranes of small vessels from hearts of patients with diabetes, myxoedema and neither disease collected post mortem, reveal that the membranes of those with diabetes are nearly three times as thick as those in normal hearts (P less than 0.001), while in patients with myxoedema they are twice normal thickness (P less than 0.001). A significant difference was demonstrated between the thickness of the basement membrane in patients with diabetes and those with myxoedema (P less than 0.001).

Adult↗
PubMed1976

Prinzmetal's angina with coronary artery spasm. Angiographic, pharmacologic, metabolic and radionuclide perfusion studies.

We studied the effects of coronary artery spasm on perfusion of the microvasculature in a patient with Prinzmetal's angina. Intracoronary injections of 99mTc and 131I-labelled macroaggregated human serum albumin were performed (1) at rest, (2) during spontaneous angina, (3) after the administration of nitroglycerin and (4) during pacing-induced spasm and the resultant scans compared. The resting scan was normal. Pain and spasm were associated with a perfusion defect that was localized to the anterior and inferior walls of the left ventricle. The localization of the perfusion defect corresponded with angiographically demonstrated spasm involving left anterior descending and distal circumflex coronary arteries. A subsequent myocardial infarction was localized by 43K scanning to the same perfusion area. Metabolic and parasympathetic stimulation studies were performed but were inconclusive. The patient's recurrent pains were ultimately controlled with large oral doses of isosorbide dinitrate.

Angina Pectoris↗
PubMed1976

Evolving indications for preoperative intraaortic balloon pump assistance.

Over a two-year period about 1,000 operations were performed with cardiopulmonary bypass. Intraaortic balloon pump assistance (IABP) was employed on 150 occasions, and a review of these has permitted clarification of the indications for its use. Sixty patients had IABP for carcinogenic shock either after infarction or cardiotomy, and 37 (62%) survived. Preoperative IABP in 90 high-risk patients resulted in survival for 79 (88%). The indications for prophylactic IABP included: (1) relief of severe pain, which occurred in 42 patients with acute coronary insufficiency, (2) improvement in the coronary perfusion pressure, which was accomplished in 20 patients with significant left main coronary artery occlusion or its equivalent, and (3) protection of left ventricular function, which war carried out in 28 patients with an LV ejection fraction of less than 0.40. The significance of the preoperative endocardial viability ratio (EVR) in relation to prophylactic IABP was also assessed: an EVR below 0.70 appears to be an indication for preoperative IABP.

Assisted Circulation↗
PubMedDate not supplied

Lisinopril in the treatment of hypertension: a Canadian postmarketing surveillance study.

A postmarketing surveillance study in 2273 Canadian office practices provided the largest body of clinical experience to date with the angiotensin-converting enzyme (ACE) inhibitor lisinopril in the treatment of mild to moderate essential hypertension. The principal emphasis in this uncontrolled study was safety, assessed in 10,289 patients. Patients with a diastolic blood pressure > 90 mmHg were considered for the study. Both previously untreated patients and those who were experiencing adverse effects from their current antihypertensive regimen were included. Lisinopril was begun at a dose of 10 mg/day. Subsequent dose adjustments, to a maximum of 40 mg/day, were made to achieve optimal blood pressure control (diastolic blood pressure < or = 90 mmHg or > or = 10 mmHg below baseline for > or = 4 weeks at the same dose). Therapy was continued for a minimum of 4 weeks to a maximum of 12 weeks, with patients examined every 2 weeks. The frequencies of adverse effects and laboratory abnormalities were analyzed in all treated patients. All 10,289 patients enrolled were considered in the analysis of safety. One or more adverse effects were reported for 1593 (15.5%) patients, and 802 (7.8%) withdrew from the study because of adverse effects. The most frequent adverse effects were cough (4.0%), dizziness (2.3%), headache (2.1%), asthenia (1.7%), and nausea (1.0%). The physicians' global assessment rated overall tolerability as very good or good for 77.1% of the patients. Antihypertensive effect was evaluated in 5886 patients who met the criteria for efficacy analysis. The criterion response was attained in 5141 (87.3%) patients, with 68.6% responding to 10 mg/day of lisinopril, 26.3% to 20 mg/day, and 3.2% to 40 mg/day (the other 1.9% responded at nonstandard doses). Lisinopril was safe and well-tolerated. Except for cough, class effects of ACE inhibitors were rarely encountered. The results of the efficacy analysis confirm the established efficacy of lisinopril in patients with mild to moderate essential hypertension.

Adult↗