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Biomedical subjects

H Kafka

Publications and source records attributed to H Kafka.

17 recordsLinked to original sources
PubMed1995

Exercise echocardiography after coronary artery bypass surgery: correlation with coronary angiography.

OBJECTIVES: Our aim was to assess, in patients after coronary artery bypass surgery, how well exercise echocardiography predicts the presence of vascular compromise on angiography. BACKGROUND: Because late graft failure frequently occurs after bypass surgery, a reliable noninvasive technique is needed to identify those patients who would benefit from angiographic study. METHODS: In 182 patients, a total of 213 symptom-limited treadmill exercise electrocardiograms (ECGs) and exercise echocardiograms were performed in association with coronary and bypass angiography 2 weeks to 21 years after bypass surgery. RESULTS: There were more inconclusive exercise ECGs (28%) than exercise echocardiograms (9%). The positive predictive value was 85% for the exercise echocardiogram versus 62% for the exercise ECG; the corresponding negative predictive values were 81% versus 52%. The accuracy of the exercise echocardiogram was linked to the degree of underlying vascular compromise. After excluding cases with nondiagnostic results, due to either submaximal stress or poor image quality, the exercise echocardiogram detected 46 of the 60 cases with vascular compromise in one region (sensitivity 77%) and 47 of the 49 cases with compromise in two or three regions (sensitivity 96%). Similarly, an abnormal exercise echocardiogram had a positive predictive value of 71% for vascular compromise in one region and 98% for compromise in two or three regions. Most false negative exercise echocardiographic results were associated with posterolateral single-region vascular compromise on angiography. CONCLUSIONS: This study confirms a high positive and negative predictive value of exercise echocardiography in the detection of vascular compromise in patients after bypass surgery. It is clearly superior to exercise electrocardiography in predicting which patients will have angiographically significant graft or arterial lesions, and it can be used to obtain a better selection of patients for angiographic study.

Coronary Angiography↗
PubMed1995

Aortocoronary vein graft spasm during angiography.

OBJECTIVE: To determine the frequency and clinical significance of aorto-coronary vein graft spasm during angiography. DESIGN: Retrospective review of angiograms and subsequent correlation with clinical outcome. PATIENTS: A total of 1264 patients having bypass surgery between 1971 and 1986. MAIN RESULTS: Twenty-four men, aged 31 to 54 years, demonstrated spasm in 31 vein grafts at angiography. Vein graft spasm occurred in 13 anterior descending, 12 right coronary, four marginocircumflex and two diagonal grafts. Spasm occurred less than six months after surgery in six cases, six to 12 months after surgery in 18 cases and five or more years after surgery in two cases. There was technical difficulty associated with the intubation of 15 of the 31 grafts. In all but two of the cases, the graft spasm was proximal. There was ischemic discomfort and/or electrocardiographic changes in nine patients, with ventricular fibrillation in three cases. Three cases of very severe vein graft spasm could be reversed with vasodilators, but in three others it could not be relieved and the grafts occluded irreversibly, leading to myocardial infarction in two patients. CONCLUSION: Aortocoronary vein graft spasm may occur during angiography and may be associated with more technically difficult graft intubation. Severe vein graft spasm may respond to vasodilators but can progress to graft occlusion with myocardial infarction. Aortocoronary vein graft spasm during angiography is not related to any higher incidence of spontaneous graft closure or recurrent angina.

Adult↗
PubMed1993

Repeated plaque rupture in the same bypass graft.

A 51-year-old man experienced a plaque rupture at the site of a shallow plaque in his anterior descending bypass graft and went on to suffer a myocardial infarct. Angiography, five months later, showed excellent recanalization; however, one month after that angiogram, the patient presented with unstable angina and evidence of plaque rupture at the same site. The presence of plaque in a graft indicates risk for future plaque rupture, but there appear to be no definite indicators to identify the specific plaque that is at highest likelihood of rupture.

Angioplasty, Balloon, Coronary↗
PubMed1987

Serum magnesium and potassium in acute myocardial infarction. Influence on ventricular arrhythmias.

Over a 13-month period, serum potassium and magnesium levels were measured in 590 patients admitted to a coronary care unit. Hypokalemia, often in the absence of diuretic use, occurred in 17% of the 211 patients with acute myocardial infarction. Patients with acute myocardial infarction and a potassium level of less than 4.0 mEq/L (4.0 mmol/L) had an increased risk of ventricular arrhythmias (59% vs 42%). Because hypokalemia is common in acute myocardial infarction and is associated with ventricular arrhythmias, routine measurement of serum potassium levels and prompt correction are recommended. Hypomagnesemia occurred in only 4% of the patients, but it was more common in the group with acute myocardial infarction than in the group without myocardial infarction (6% vs 3%). Ventricular arrhythmias occurred in ten of the 13 patients with both acute myocardial infarction and hypomagnesemia, but eight of these patients also had low serum potassium levels. This low incidence of hypomagnesemia does not justify routine measurement of serum magnesium levels. However, the mean level (2.5 +/- 0.4 mg/dL [1.03 +/- 0.16 mmol/L]) in a reference population of healthy volunteers was unexpectedly high and suggests that the low incidence of hypomagnesemia in our population may not be applicable to other centers and may reflect a higher magnesium content in our geographic area of southeastern Ontario.

Acute Disease↗
PubMed1985

Electrocardiographic diagnosis of left ventricular hypertrophy in the presence of left bundle branch block: an echocardiographic study.

This study tests the electrocardiographic diagnosis of left ventricular (LV) hypertrophy in the presence of left bundle branch block (BBB). The LV mass of 125 patients with left BBB was estimated by echocardiography. M-mode echocardiography was technically adequate in 80% of patients. LV mass was calculated using previously validated M-mode formulas and then indexed to body surface area. The known shifts in the QRS voltage and axis with the onset of left BBB led to the selection of 4 electrocardiographic parameters for the diagnosis of LV hypertrophy: R in aVL 11 or more; QRS axis -40 degrees or less (or SII greater than RII); SV1 + RV5 to RV6 40 or more; SV2 30 or more and SV3 25 or more; these parameters were used in cumulative fashion. This cumulative approach was superior to using single conventional criterion such as the SV1 + RV5 or RV6. When LV hypertrophy was defined as an M-mode index of at least 115 g/m2, the sensitivity was 75% and specificity 90%. Using an M-mode mass of at least 215 g as the standard, the sensitivity was 73% and the specificity 66%. LV hypertrophy can be diagnosed by electrocardiographic criteria in the presence of left BBB at least as reliably as in normal conduction.

Adult↗
PubMed1983

Malfunction in a St. Jude medical mitral valve prosthesis: a clinical diagnostic dilemma.

Thrombosis of one leaflet of a St. Jude medical prosthetic mitral valve in a 49-year-old man resulted in prosthetic malfunction causing cardiac failure. Clinical and echocardiographic assessment did not adequately distinguish between abnormal valve function and left ventricular dysfunction as the responsible lesion. Hemodynamic study revealed a gradient across the mitral valve and poor left ventricular function. At operation it was found that thrombus had caused one of the leaflets to stick in an almost open position. This malfunction was attributed to lack of adequate anticoagulation and to the impingement of a piece of papillary muscle on the prosthesis. A definite echocardiographic pattern for malfunction of the St. Jude valve has not been established. However, it is clear that loudness of prosthetic valve sounds cannot be used as a guide to normal function in a bileaflet valve.

Electrocardiography↗
PubMed1976

Blood flow and venous distensibility in the upper and lower extremities of newborn infants.

The electrocapacitance plethysmograph was utilized to measure peripheral blood flow and venous distensibility in 17 newborn infants and 20 adults. Measurements were made in the upper and lower extremities in each subject under identical environmental conditions. Blood flow in the forearm and calf were found to be significantly higher in infants than adults. In infants there were no significant differences in the blood flow between the upper and lower extremities. In contrast, in the adults, the blood flow was significantly higher in the upper than in the lower extremities. Similarly, venous distensibility was observed to be higher in infants than in adults. While no significant differences were observed in the venous distensibility between the upper and lower extremities in infants, the venous distensibility was found to be higher in the forearm than in the leg in adults.

Adult↗
PubMedDate not supplied

A new surgical technique to correct double chambered right ventricle associated with anomalous left anterior descending coronary artery.

A 42 year old woman with symptomatic double chambered right ventricle had the additional features of an anomalous left anterior descending coronary artery and attachment of the tricuspid valve to the area of subinfundibular stenosis which precluded conventional repair. A non-valved Dacron conduit was used to bypass the obstruction. The patient is asymptomatic two years later.

Adult↗