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Biomedical subjects

F W Amann

Publications and source records attributed to F W Amann.

At least 19 recordsLinked to original sources
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↗
PubMed1992

Relation of the level of high-density lipoprotein subfractions to the presence and extent of coronary artery disease.

Plasma lipid profiles, including high-density lipoprotein (HDL) subfractions HDL2 and HDL3, were obtained in 115 men undergoing coronary angiography to assess the relation of lipid levels to coronary artery disease (CAD). CAD was present in 87 patients (76%) and absent in 28 (24%). The largest difference between the 2 groups were observed for HDL2 cholesterol, with a mean of 0.13 mmol/liter (5 mg/dl) in patients with CAD compared with 0.25 mmol/liter (10 mg/dl) in those without CAD (p less than 0.005). Smaller differences were found for HDL3 (1.02 mmol/liter [39 mg/dl] vs 1.19 mmol/liter [46 mg/dl]; p less than 0.005) and HDL (1.15 vs 1.42 mmol/liter [45 vs 55 mg/dl]; p less than 0.001) cholesterol, and apolipoprotein A-1 (1.37 vs 1.50 g/liter; p less than 0.01) and plasma triglycerides (1.79 vs 1.38 mmol/liter [159 vs 122 mg/dl]; p less than 0.05). No significant difference was found for plasma and low-density lipoprotein cholesterol, and apolipoprotein B levels. Simple regression analysis revealed that the most powerful independent variable associated with the extent of CAD was HDL2 cholesterol (Spearman rho = 0.311; p less than 0.001). Stepwise multiple regression analysis proved HDL2 cholesterol and age to be the strongest predictors of extent of CAD. The level of HDL2 cholesterol was reasonably well correlated with HDL cholesterol (r2 = 0.6; p less than 0.0001), but less so with plasma apolipoprotein A-1 (r2 = 0.4; p less than 0.0001). The data add to the growing body of information demonstrating an important association of HDL (and more specifically HDL2) with CAD in men.

Age Factors↗
PubMed1992

[Epidemiology and pathophysiology of heart failure].

The role of coronary artery disease in the epidemiology of congestive heart failure is important. In the pathophysiologic process of congestive heart failure, a number of adaptive mechanisms (hypertrophy, dilatation, neurohumoral stimulation) compensate for the decreased cardiac output by the failing heart. A new understanding of the pathophysiology of heart failure has lead to the identification of important cellular alterations. In the final stage of overcompensation these adaptive mechanisms are deleterious. Associated ventricular arrhythmias indicate a high incidence of sudden cardiac death. Recent considerations of clinical relevance are taken into account in tailoring treatment for patients with congestive heart failure.

Autonomic Nervous System↗
PubMed1992

[Clinical aspects of arrhythmias].

Arrhythmias are frequent and occur in normal individuals as well as in patients with structural heart disease. In supraventricular arrhythmias the indication for treatment is mainly based on symptoms. In atrial fibrillation the thromboembolic risk has to be taken into account. In ventricular arrhythmias, especially in combination with significant structural heart disease, prognostic considerations play an important role in decision-making.

Arrhythmias, Cardiac↗
PubMed1992

[Electrophysiology: indications for and results in programmed stimulation].

Since the early seventies electrophysiology is a diagnostic tool to evaluate mechanisms of arrhythmias and to control drug therapy. Advances in technology have led to newer methods, such as radiofrequency ablation and the use of implantable defibrillators. These techniques as well as their diagnostic, prognostic and therapeutic indications will be discussed.

Arrhythmias, Cardiac↗
PubMed1992

[Anti-angina effect of amiodarone in therapy-resistant angina pectoris].

In a double-blind randomized trial 63 patients on the waiting list for coronary artery bypass grafting, with stable angina NYHA III and a positive stress test on triple (nitrates, beta- and calcium entry blockers) combination therapy, were studied for an additional antianginal effect of amiodarone over a period of 2 months. In the treatment group an increase in exercise duration and a decrease of the double product and of ST-depression were noted. Thus, amiodarone is an effective antianginal agent in patients with limiting angina pectoris on conventional triple therapy.

Adrenergic beta-Antagonists↗
PubMed1992

[Malignant ventricular arrhythmia in congenital aneurysms of the left ventricle in adulthood].

Congenital aneurysms of the left ventricle (ALV) are rare cardiac lesions. Beyond that an association with malignant ventricular arrhythmias (MVA, symptomatic ventricular tachycardia--VT or ventricular fibrillation--VF) is reported only in sporadic cases. Since 1988 we had the opportunity to study 5 patients (pts) with MVA (4 sustained VT, 1 VF; 1 female, 4 males; mean age 38 years) without cardiovascular risk factors, history of myocardial infarction, trauma or inflammatory disease. Left ventricular contrast angiography and echocardiography disclosed ALV's. At programmed electrical stimulation clinically documented MVA (4 VT, 1 resuscitated VF) were reproducible in all 5 cases, the respective VT was located in the area of the ALV in 4 cases. In 2 pts aneurysmectomy combined with subendocardial resection and cryotherapy (1 apical, 1 posterobasal ALV) was performed. In both pts histopathology confirmed a congenital disorder, without evidence of inflammatory lesions. In 2 pts MVA was controlled with antiarrhythmic therapy. The pt with VF and an ALV adjacent to the anulus of the aortic valve received an implantable cardioverter defibrillator. In congenital aneurysms of the left ventricle complicated by malignant ventricular arrhythmias surgical intervention offers a potential cure in selected cases.

Adolescent↗
PubMed1991

[Clinical experience with a second-generation cardioverter-defibrillator].

Implantable cardioverter defibrillators (ICD's) are effective for reducing mortality in refractory malignant ventricular arrhythmias (MVA). Second generation ICD's (Telectronics Guardian 4202/4203) were implanted in 7 patients (all male, mean age 58.1 years) with ventricular fibrillation (VF) in 2, ventricular tachycardia (VT) in 1, and both VF and VT in 4. Underlying heart disease was coronary artery disease in 4 patients, and valvular heart disease, dilated cardiomyopathy and no obvious cause (documented primary VF, reproducible at electrophysiologic study) in 1 patient each. Mean ejection fraction was 40 +/- 14%. Mean defibrillation threshold of the two epicardial patches at implantation by means of median sternotomy was 18 +/- 9 joule, and patch impedance 35 +/- 7 ohms. Post defibrillation bradypacing via epicardial electrode was programmed in 5 patients (70%). Mean follow-up was 10.1 months (1-25 months). Successful defibrillation of 28 spontaneous VT/VF episodes was noted in 2 patients, while the other 5 have had no further episodes of MVA so far. One device was explanted following tissue necrosis at the battery site after a MVA-recurrence-free interval of 15 months. The reconfirmation algorithm prevented false shock delivery in 2 patients.

Cardiac Pacing, Artificial↗
PubMed1991

Activity-sensing rate responsive versus conventional fixed-rate pacing: a comparison of rate behavior and patient well-being during routine daily exercise.

Rate responsive single chamber pacing (VVIR) may be the pacemaker of choice in patients who are not suitable candidates for a dual chamber system. Several studies, most of them performed in an exercise laboratory, have shown a significantly higher exercise capacity demonstrating an improvement in cardiac output and anaerobic threshold compared to conventional fixed rate pacing (VVI). Expressing our idea that stress testing in an "artificial environment" on a bicycle or motor driven treadmill has its limitations and may be difficult to extend into patient's daily life, we designed an outdoor study imitating patient's daily activity. Twenty-one patients with an activity-sensing rate responsive pacemaker performed in a double blind fashion in VVI and VVIR mode the following test circuit: walking 170 meters on flat ground, 210 meters incline, climbing a flight of stairs, and the same circuit in reverse order, and therefore "downhill". Heart rate behavior was recorded by Holter monitoring and patients subjective feelings of well-being, i.e. fatigue and dyspnea were also evaluated. VVIR pacing responded promptly to exercise, i.e., walking on a flat ground, but no further significant increase in pacing rate was observed in relationship to the strength of physical activity while walking inclined or climbing stairs. While patients became exhausted, a nonphysiological decrease in heart rate sometimes occurred. Despite these limitations 6 of 12 patients who had a paced-only rhythm while exercising in both VVI and VVIR mode reported feeling significantly better in the VVIR mode, expressing less dyspnea and fatigue. In contrast, two of nine patients having only intermittently paced rhythm preferred the VVIR mode. Patients with lower ejection fraction (EF) were more likely to show subjectively a benefit while exercising in VVIR mode, compared to those with less reduced or normal EF. Despite the technical limitations of using a piezo crystal for rate adaptation, VVIR pacing is an important option in paced-only patients, but it seems less beneficial in patients with only intermittent paced rhythm.

Activities of Daily Living↗
PubMed1991

[Rhythm disorders and infarction].

Ventricular arrhythmias are a frequent complication of myocardial infarction. In either the acute or the late stage, ventricular tachycardia and ventricular fibrillation represent the most common cause of cardiac death. About 15% of the patients with acute myocardial infarction die before entering the hospital, the majority due to ventricular fibrillation. Another 10 to 15% of the survivors of an acute myocardial infarction die suddenly within the subsequent year, again mostly due to ventricular arrhythmias. Independent risk factors for sudden cardiac death consist of depressed left ventricular function, persistent electrical instability (e.g. repetitive and complex VPB's, documented 'late potentials', inducibility of arrhythmias at programmed electrical stimulation), new onset complete-bundle branch block and large aneurysm of the left anterior ventricular wall. Bradyarrhythmias (i.e. high-degree AV-Block, asystole) are a far less common etiology of sudden cardiac death caused by an ischemic lesion to the conduction system. Betablockers have a well-known benefit in secondary prevention, whereas antiarrhythmic agents (with the exception of amiodarone) are ineffective in asymptomatic patients or may even increase the risk for sudden death due to a proarrhythmic effect (class IC); therefore, the latter are not recommended in asymptomatic patients with documented VPB's and preserved left ventricular function. The prognosis of patients with sustained VT and VF is poor. Their outcome is improved in responders to an individual antiarrhythmic therapy with serial drug testing or with subendocardial resection of localized areas and by implantation of a cardioverter defibrillator.

Adrenergic beta-Antagonists↗
PubMed1990

[Can sudden death be prevented by drugs?].

Sudden cardiac death continues a major health problem. It is the leading cause of mortality in patients with coronary artery disease. In patients with the most malignant forms of ventricular tachyarrhythmias (ventricular tachycardia with syncope or aborted sudden death), anti-arrhythmics have been shown to be effective in preventing recurrences of these arrhythmias when tested according to a systematic protocol. Empiric therapy, on the other hand, is ineffective and dangerous because of the limited efficacy and the pro-arrhythmic potency of all anti-arrhythmic drugs. Asymptomatic ventricular arrhythmias, especially complex forms, after myocardial infarction characterize patients at increased risk for sudden cardiac death. In this situation most anti-arrhythmics do not improve prognosis. Amiodarone is so far the only anti-arrhythmic drug which has been shown to be beneficial in postinfarct patients, whereas Flecainide and Encainide were deleterious in a population at relatively low risk. Beta blocking agents, however, are effective in reducing mortality and incidence of sudden cardiac death in patients after myocardial infarction.

Adrenergic beta-Antagonists↗
PubMed1990

Late recurrent ischemia in infarct patients with a normal predischarge exercise test after thrombolysis.

We investigated the prognostic value of normal predischarge exercise test in 109 patients after myocardial infarction treated with i.v. thrombolysis within 4 h. In 29 of these 109 patients, elective PTCA or bypass surgery was performed for prognostic reasons after coronary angiography; 80 patients were treated conservatively with drug therapy. Recurrent postinfarct angina early after hospital discharge was the reason in 4 of 80 for PTCA or bypass surgery. Twenty-three of the remaining 76 conservatively treated patients developed recurrent ischaemia during long-term follow-up of 12.0 +/- 6.2 months, including one patient with reinfarction. Late recurrent ischaemia during long-term follow-up was observed in one third of the conservatively treated patients with a normal predischarge exercise test, although a high percentage (30%) of patients in this subgroup had been treated with PTCA or bypass surgery mainly for prognostic reasons. Predischarge exercise test is therefore of limited value for detection of still viable myocardium at risk of further ischaemic events after acute myocardial infarction and thrombolysis.

Aged↗
PubMed1989

[Isolated spontaneous coronary dissection].

Spontaneous coronary artery dissection is a rare cause of myocardial infarction. It occurs most commonly in young, otherwise healthy women, especially in the peripartum period. Dissections are most often located in the proximal part of the left coronary artery. Histologically a hematoma is found in the media with compression of the true lumen and usually a localized periadventitial inflammation. The etiology of the disease is unknown; hormonal influences and defective collagen metabolism are discussed. Prognosis is poor; only one third of patients survive the first 24 hours after acute onset of symptoms, and mortality is high in the following days and weeks. Surgery may prevent extension of infarction, and for this reason early diagnosis by coronary angiography is essential in patients at risk for this disease. Two cases of coronary dissection are described, followed by a review of the literature and discussion of etiology, prognosis and management.

Adult↗
PubMed1989

Sudden cardiac death after aortic valve surgery: incidence and concomitant factors.

A retrospective analysis of 599 consecutive patients after aortic valve surgery aged 7-82 years (mean 56) was performed. During a follow-up of 1-14 years (mean 4.7 years) a 4-week perioperative mortality of 6.9% and a late annual mortality of 3.6% were observed. Sudden cardiac death was the most frequent single cause of death, accounting for 24% of all deaths. Patients dying suddenly were younger than patients dying from other causes (51 +/- 17 vs. 59 +/- 14 years, p less than 0.05) and showed more left ventricular hypertrophy by electrocardiographic criteria when compared with matched survivors (mean Estes score 5.2 +/- 2.4 vs. 2.8 +/- 1.9; p less than 0.01) and with patients dying nonsuddenly (mean Estes score 5.2 +/- 2.4 vs. 1.8 +/- 1.8; p less than 0.01). Ventricular premature beats in the resting electrocardiogram were more prevalent in patients dying suddenly than in matched survivors (55 vs. 20%; p less than 0.025) as well as in patients dying from other causes (55 vs. 25%; p less than 0.05). In addition, there were more intracardiac conduction disturbances and more ungrafted coronary vessels with insignificant stenoses at the time of surgery in sudden death patients. Our findings suggest that after aortic valve replacement patients with left ventricular hypertrophy, bundle-branch block, and ventricular premature beats in the resting electrocardiogram are at increased risk for sudden cardiac death. A possible etiological role of concomitant coronary artery disease must be considered.

Adolescent↗
PubMed1989

[Check-up examinations from the cardiologic viewpoint].

The concept of the primary prevention of coronary disease is certainly widely accepted today and supports check-up visits of apparently healthy persons. The goals of check-up's viewed by the cardiologist are the detection of coronary risk factors and the identification of asymptomatic patients with coronary disease to initiate preventive measures. In some instances, a personal health problem forces the patient to a check-up visit. The major coronary risk factors of heredity, cigarette-smoking, hypercholesteremia, hypertension can be detected by taking the history, performing a physical examination and a blood-sampling for cholesterol. Additional investigations such as an ECG or an exercise-test are only indicated in symptomatic patients or in persons at high coronary risk.

Blood Pressure↗