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Biomedical subjects

F W Amann

Publications and source records attributed to F W Amann.

At least 55 records · Page 3Linked to original sources
PubMed1995

Reversal of atherosclerotic obstructions by percutaneous transluminal angioplasty raises high-density lipoprotein cholesterol.

Variation of high-density lipoprotein cholesterol (HDL) levels in man show a strong inverse relationship to the incidence of atherosclerotic vascular disease. Conversely, effects of atherosclerosis and ischemia on lipoprotein metabolism are unclear. We investigated 41 patients, 10 women and 31 men, undergoing percutaneous transluminal angioplasty by measuring fasting lipoprotein cholesterol including high-density lipoprotein subfraction analysis before and one as well as 12 weeks after the procedure. Successful reopening of a haemodynamically significant iliac, femoral or popliteal obstruction was achieved in all patients. A highly significant (p < 0.001) increase of HDL cholesterol from 1.10 +/- 0.05 to 1.31 +/- 0.06 mmol/l was revealed 12 weeks later. This was due to a significant (p < 0.001) increase in HDL3 cholesterol by 26%, whereas HDL2 cholesterol did not change significantly. We conclude that HDL cholesterol levels increase after recanalization of a significant atherosclerotic obstruction which may be a direct effect of reperfusion or an indirect effect due to an increase in exercise tolerance.

Adult↗
PubMed1994

Relation of cyclosporine blood levels to adverse effects on lipoproteins.

Hyperlipidemia is common in renal allograft recipients. To elucidate the role of cyclosporine in posttransplant hyperlipidemia, we measured lipids, lipoprotein lipids, and apolipoproteins of thirty-five renal allograft recipients and evaluated their relation to trough cyclosporine blood levels. All patients were on a triple immunosuppressive regimen with equal doses of prednisone and azathioprine, and had stable graft function. Cyclosporine blood levels were significantly correlated to total plasma cholesterol (P = 0.028), low-density lipoprotein cholesterol (P = 0.022), apolipoprotein B (P = 0.017), and the cholesterol/high-density lipoprotein cholesterol ratio (P < 0.002), but not to plasma triglycerides. Significant inverse correlations were found between cyclosporine blood levels and high-density lipoprotein cholesterol (P = 0.034), high-density lipoprotein3 cholesterol (P = 0.025), and apolipoprotein A-1 (P = 0.047), but not high-density lipoprotein2 cholesterol. The independent relation of cyclosporine blood levels to each of the measured lipid parameters was investigated by a stepwise regression model including age, body mass index, interval from transplantation, diabetes mellitus, plasma creatinine, and intake of diuretics and beta-blockers. After correction for these 7 variables, cyclosporine blood levels remained significantly associated with high-density lipoprotein cholesterol, high-density lipoprotein3 cholesterol, apolipoprotein A-1, apolipoprotein B, low-density lipoprotein cholesterol, and the cholesterol/high-density lipoprotein cholesterol ratio. These data suggest that cyclosporine causes atherogenic dyslipidemia.

Adult↗
PubMed1994

Surgical revascularization in acute myocardial infarction.

To determine the potential benefit of myocardial revascularizations in acute myocardial infarction we analyzed a consecutive series of 641/3397 patients with stable or unstable angina in Canadian Heart Association Class IV divided into five groups: A) unstable angina (ECG S-T modifications), B) evolving infarction (new Q-wave, CK more than 3 times normal), C) mechanical complications (ventricular septal defect (VSD), wall rupture, acute mitral regurgitation), D) coronary artery occlusion (crashed percutaneous transluminal coronary angioplasty (PTCA)), and E) stable angina class IV (control group). The mean follow-up was 72 +/- 33 months (range 24-144 months). Of the 641 patients 362 were unstable (A), 22 had evolving infarction (B), 20 suffered from mechanical complications (C), 48 had acute coronary artery occlusion (D), and 189 were in the control group (E). There was no difference for left ventricular (LV) ejection fraction before surgery (P < 0.05 = * as compared to control (E)), however cardiogenic shock was present before surgery in 13/362 (4%) for unstable angina, 5/22 (23%) for evolving infarction, 6/20 (30%) for mechanical complications, 4/48 (8%) for acute occlusion, and none of the controls. The number of bypasses was 3.8 +/- 1.3* for unstable angina, 3.6 +/- 1.3 for evolving infarction, 2.3 +/- 1.2* for mechanical complications, 2.0 +/- 1.2* for acute occlusion, and 3.4 +/- 1.5 for control. Intra-aortic balloon pumping was necessary in 26/362 (7%) for unstable angina, 5/22 (23%*) for evolving infarction, 7/20 (35%*) for mechanical complications, 7/48 (15%*) for acute occlusions, and 5/189 (3%) of the controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Treatment of internal mammary artery malperfusion syndrome by additional venous graft: early postoperative angiographic results.

BACKGROUND: Internal mammary artery malperfusion syndrome is caused by an acute imbalance between myocardial demand and nutritional support through the mammary artery. METHODS: We performed early angiography in 11 consecutive patients in whom the perioperative course suggested mammary artery malperfusion. All patients received an additional saphenous vein graft distally to the mammary artery anastomosis. RESULTS: Postoperative angiography revealed patent mammary artery and vein graft in 10 patients (three with a markedly reduced caliber of the arterial graft). CONCLUSION: Additional vein graft is the treatment of choice in mammary artery malperfusion syndrome; it does not lead to occlusion of the internal mammary artery.

Coronary Angiography↗
PubMed1994

Plasma triglycerides and three lipoprotein cholesterol fractions are independent predictors of the extent of coronary atherosclerosis.

BACKGROUND: The lipoprotein system has manifold links to atherosclerotic disease. LDL cholesterol is related to lesion formation and growth. The cholesterol of HDLs is indicative of protection against atherosclerosis. The status of triglycerides and of subfractions of high-density lipoproteins as risk factors is less certain. Also, the magnitude of the atherogenic/protective power of these factors is not known. METHODS AND RESULTS: Five hundred patients (418 men and 82 women) were enrolled in an angiographic study. A total of 1006 coronary lesions with > or = 50% narrowing were recorded as study end points. By extent of atherosclerosis, defined as the number of > or = 50% lesions, the study subjects were allocated to one of four ordered categories with 0, 1 to 3, 4 to 6, or 7 to 10 lesions, respectively. Subfractions of HDL cholesterol were determined by a dual precipitation method. By a polychotomous logistic regression model, it was found that, besides age and sex, LDL cholesterol, HDL2 cholesterol, HDL3 cholesterol, and triglycerides were independently predictive (P < .05) of the extent of coronary atherosclerosis. An increase in age by 10 years was associated with an increase of the odds ratio for falling into a higher-extent category by a factor of 1.64, and the same increase of the odds ratio was obtained by increasing LDL cholesterol by 0.92 mmol/L or triglycerides by 1.01 mmol/L and by decreasing HDL2 cholesterol by 0.20 mmol/L or HDL3 cholesterol by 0.46 mmol/L. The less sensitive coronary end point, presence of atherosclerosis (ie, observation of > or = 1 lesion of > or = 50%) depended significantly on age, sex, LDL cholesterol, and HDL2 cholesterol, but not on HDL3 cholesterol or triglycerides. CONCLUSIONS: In addition to LDL, HDL2, and HDL3 cholesterol, triglycerides also proved independently predictive of the extent of coronary atherosclerosis.

Cholesterol, HDL↗
PubMed1994

Ventricular fibrillation in a patient with exercise-induced anaphylaxis, normal coronary arteries, and a positive ergonovine test.

Exercise-induced anaphylaxis (EIA) is a rare form of physical allergy. Although histamine release is a feature of EIA, and histamine provocation of coronary spasm has been described, serious cardiac arrhythmias in EIA have not been reported. Exercise-induced anaphylaxis was diagnosed in a survivor of out-of-hospital cardiac arrest due to ventricular fibrillation after ECG signs of coronary spasm. Coronary artery disease was excluded. Ergonovine provocation induced coronary spasm in this patient. This is, to the authors' knowledge, the first description of ventricular fibrillation in EIA, possibly due to coronary spasm.

Anaphylaxis↗
PubMed1993

[Lipids and blood vessels].

The key lesion in atherosclerosis is termed atheroma. It consists of intracellular and extracellular cholesterol esters. Because atheromas are located subendothelially, an interrelation with blood cholesterol has long been suspected. In the blood, cholesterol is wrapped in lipoproteins, with the largest amount being found in low-density lipoproteins (LDL), whereas a smaller amount is found in high-density lipoproteins (HDL). LDL (and their cholesterol) are removed from the plasma by receptor-mediated uptake. Impaired LDL-receptor interaction results in accumulation of LDL in plasma. LDL now penetrate the endothelial layer and become deposited in the arterial intima. This process initiates atheroma formation. Excess tissue cholesterol (e.g. in the arterial intima) is returned to the liver by HDL. The HDL2 subfraction is particularly effective in this reverse cholesterol transport. Patients with coronary atherosclerosis either have a defect in reverse cholesterol transport (i.e. low HDL2 levels) or an excess in cholesterol load (i.e. high LDL). The ratio between LDL and HDL2 cholesterol determines the risk for atherosclerotic disease. Triglycerides lower HDL2 levels and thereby exert indirect atherogenicity.

Arteriosclerosis↗
PubMed1993

[Heart pacemaker therapy: a guideline for clinical practice].

Pacemakers have evolved enormously over the past 15 years because of technical developments in the field of microprocessors. Implantation of physiologic dual chamber systems (DDD pacemakers) have gained growing importance. The goal of therapy with modern pacemakers is to relieve symptoms under rest as well as under hemodynamic load. Next to indications for and explications on the function of the various systems (single and dual chamber systems, rate responsive pacemakers) this article covers hemodynamic consequences of pacemaker implantation. Particular reference is made to the follow-up of patients with pacemakers and to the possibility of external interference with these devices. A glossary of pacemaker therapy is given in the appendix.

Aftercare↗
PubMed1993

[Surgery for arrhythmia in patients with therapy-resistant ventricular tachycardia].

We reviewed the data of 42 consecutive patients (mean age 55 +/- 12 years) who underwent surgery for control of recurrent drug-refractory ventricular arrhythmia. A history of myocardial infarction was present in 38 patients, 4 patients had congenital heart disease (2 aneurysms, 1 right ventricular dysplasia, 1 hamartoma). The mean LV ejection fraction was 40 +/- 14%. At preoperative electrophysiologic study, ventricular tachycardia was inducible in 32 of 33 patients. The mean heart rate was 188/min. A mean of 3.3 +/- 2.1 antiarrhythmic drug trials were ineffective. The most frequently performed surgical procedure (n = 36) was visually guided subendocardial resection, alone or in combination with cryothermal ablation. In 30 patients additional aneurysmectomy was performed. A mean of 1.9 +/- 1.4 coronary arteries in 32 patients were bypassed. The overall in-hospital mortality (30 days) was 9.5% (1 arrhythmic death, 1 pump failure, 1 sepsis, 1 hemorrhagic shock). We found 2 significant (p < 0.05) predictors of perioperative mortality: recent myocardial infarction and patient's age. During a mean follow-up of 33 months (range 1 to 90), there were 3 sudden cardiac deaths and 6 nonfatal recurrences of ventricular tachycardia which were subsequently prevented with antiarrhythmic drug therapy. Thus, the overall success in control of arrhythmia was 92%, in 59% by surgery alone. Survival was 79% at 2 years after surgery and 63% at 5 years. We conclude that patients who have successful subendocardial resection and aneurysmectomy for control of ventricular arrhythmia have an excellent chance of arrhythmia-free survival and a relatively good prognosis.

Adolescent↗
PubMed1993

[Right ventricular dysplasia (right ventricular cardiomyopathy). Clinical aspects, diagnosis and course in 15 patients from the Zurich area].

Fifteen patients (8 men, 7 women) with right ventricular dysplasia (RVS) from the greater Zürich area are described. Two thirds of these patients were younger than 30 years at first manifestation. 12 presented with ventricular tachycardia of left bundle branch block type. Other forms of arrhythmia (supraventricular tachycardia, sinus node dysfunction) or condition disturbances were documented in 9 subjects. 6 patients had additional symptoms of congestive heart failure; in 3 of them this was the only symptom. 12-lead ECG at rest showed precordial T-negativity (1 pacemaker ECG not interpretable) in 14/15 subjects. Signal averaged ECG revealed late potentials as well as spectral turbulence in the Y or Z leads. Echocardiography yielded typical local abnormalities in the whole study cohort and all but 2 patients showed decreased right ventricular ejection fraction and right heart dilatation. Moreover, left ventricular ejection fraction was concomitantly impaired in 6 subjects. 4 of these 6 individuals suffered from further impairment of left ventricular function within a time period of 19 to 47 months. Recurrent ventricular tachycardia was documented in 11 patients. 2 subjects underwent heart transplantation because of severe progressive right heart failure. One subject died shortly after diagnosis and autopsy confirmed nearly total absence of right ventricular myocardium. This extreme form of right ventricular dysplasia corresponds to Uhl's anomaly. Thus, recurrent ventricular arrhythmias, in particular ventricular tachycardia of left bundle branch block type, together with precordial T-negativity without signs of ischemic heart disease, is highly suggestive of RVD. Echocardiography allows reliable diagnosis. Concomitant left ventricular involvement is frequent. Considering that the etiology and pathogenesis of this disease are unknown, the term right ventricular cardiomyopathy, rather than right ventricular dysplasia, seems more accurate.

Adult↗
PubMed1993

[Possibilities of catheter therapy in vascular stenosis, vascular abnormalities, tumors and hemorrhages. Synopsis of an interdisciplinary colloquium].

Modern interventional catheter-technics allow amelioration of arterial blood flow by dilatation of narrowed or recanalization of closed coronary and peripheral arteries. Patients with chronic or unstable angina pectoris not responding to therapy can thus be treated successfully by percutaneous dilatation (PTCA). In peripheral occlusive disease balloon catheterization sometimes in combination with local fibrinolysis and thrombectomy may prevent amputation. On the other hand, cerebral malformations of arteries, aneurysms and tumors can be eliminated by artificial occlusion. Therapeutic embolization is also increasingly used in acute or recurrent haemorrhage in lungs, spleen and gastrointestinal tract. It may also be used as palliating therapy in malignancies. Medical indications and limitations of the various catheter techniques in cardiology, angiology, neurology and interventional radiology are discussed.

Angioplasty, Balloon↗
PubMed1993

[Clinical late results following surgical ablation of an accessory atrioventricular connection in Wolff-Parkinson White syndrome].

All patients operated because of WPW-syndrome between 1980 and 1990 at the University clinics of Zürich were followed up by clinical examination and by electrocardiography. Relief from symptoms (tachycardia, vertigo and/or syncopes) was defined as "symptomatic" success, lack of preexcitation in the ECG at rest as "surgical" success. Overall 56 patients (40 men, 16 women) aged from 13 to 66 years had been operated in the stated time period. Before operation 52 of these patients had pre-excitations in the ECG, 54 had tachycardia and 23 had syncopes. None of the patients died from the operation. In order to localize the AAVVs epicardial cartography was performed in all patients during operation before the AAVVs were cut through an endocardial access. The follow-up was possible after an average interval of 5.5 years (1-120 months) in 50 of the 56 patients. One patient died 10 years after operation from heart failure. 6 patients were reported to be out of the country. The follow-up revealed symptomatic success of the intervention, defined as absence of tachycardia, in 88% (44 out of 50). In 84% (42 out of 50) also a surgical success of the operation was found. In these patients the accessory atrio-ventricular bundle had been successfully ablated, and they were free of tachycardia and of preexcitation in the ECG. Two patients with persisting preexcitation remained free of clinical symptoms. Insofar the rate of symptomatic success was higher than the rate of surgical success. Summarizing the results surgical transsection (ablation) of an accessory atrioventricular bundle in patients with WPW-syndrome is a good therapeutic option with favorable long term success. It has today still its place--in selected cases--as alternative to the now available radio-frequency ablation.

Adolescent↗
PubMed1993

Additional antianginal efficacy of amiodarone in patients with limiting angina pectoris.

Sixty-three patients with stable angina New York Heart Association (NYHA) class III and a positive stress test despite triple therapy were randomized to a double-blind protocol, receiving either placebo or amiodarone in a dose of 600 mg/day for 10 days, followed by 400 mg/day for an additional 10 days, and then by 200 mg/day over a total period of 2 months. Comparable bicycle exercise times were observed at baseline in the amiodarone group (6.0 +/- 1.6 minutes) and in the placebo group (6.0 +/- 1.8 minutes). With amiodarone, there was a increase in exercise duration of 6.7 +/- 2.2 minutes versus 6.3 +/- 2.2 minutes at 1 month and 7.5 +/- 2.1 minutes versus 6.2 +/- 1.7 minutes at 2 months (p < 0.05). Also, the amiodarone group had a significant decrease in the double product when compared with the placebo group at 1 month (14,134 +/- 3,316 versus 17,570 +/- 4,092 mm Hg/min, p < 0.001) and at 2 months (14,022 +/- 3,303 and 17,298 +/- 4,872 mm Hg/min, p < 0.001). The degree of ST segment depression at peak exercise was also significantly reduced. Combination therapy of amiodarone with conventional antianginal therapy is well tolerated and results in a significant improvement in exercise capacity and a mild reduction of symptoms in patients who have continued, limiting angina pectoris with conventional triple therapy.

Aged↗
PubMed1993

Premature ICD battery depletion due to a defective lead adapter component: usefulness of extensive data logging.

Described herein is the usefulness of extensive data logging of third generation ICDs in a patient with premature ICD battery depletion due to a defective pace/sensing lead component. Due to noise artifacts, VT/VF detections occurred leading to inappropriate patient shock discharges and 2,267 internal charge dumps within 2 weeks. During manual manipulations at the ICD site, real-time intracardiac electrocardiogram and event markers revealed noise artifacts that were interpreted as VT/VF. Radiography confirmed slight movement of the pace/sensing lead pin out of the Y-adapter. Therefore, the design of adapter systems without screw fixation should be reviewed to ensure lead integrity. In the case of sudden increases in VT/VF recognition, defective sensing components must be considered.

Electric Power Supplies↗
PubMed1993

[Arrhythmias and heart failure].

Numerous factors contribute to the genesis of arrhythmias and sudden cardiac death in patients with congestive heart failure. Fibrosis of myocardium, ischemia, dilatation of the ventricles and atria, electrolyte imbalance, and neurohumoral factors are examples. Various drugs used in the treatment of congestive heart failure can also precipitate serious arrhythmias. The role of antiarrhythmics, including amiodarone, is still controversial. Judicious antiarrhythmic therapy involves weighing potential benefits of such therapy against risks, such as worsening heart failure or proarrhythmia. In patients with heart failure antiarrhythmic drugs should only be used for symptomatic arrhythmias. Low-dose beta-blockade offers a promising measure for the prevention of sudden cardiac death even in patients with symptomatic congestive heart failure.

Anti-Arrhythmia Agents↗