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Biomedical subjects

H Schmidinger

Publications and source records attributed to H Schmidinger.

At least 37 records · Page 2Linked to original sources
PubMed1995

The impact of implantable cardioverter-defibrillators on mortality among patients on the waiting list for heart transplantation.

Implantable cardioverter-defibrillators were investigated for their impact on mortality in 228 consecutive heart transplant candidates on the waiting list for transplantation (207 patients without and 21 with implantable cardioverter-defibrillator therapy). The mortality rate in 207 patients without implantable cardioverter-defibrillator therapy was 23.2% and in 21 patients with implantable cardioverter-defibrillator therapy was 4.7%. In a Cox proportional hazards model for all 228 study patients (mortality while on the waiting list: 21.5%; transplantation rate: 54.8%), the absence of an implantable cardioverter-defibrillator was only a marginally significant predictor of mortality (p = 0.079). However, the absence of an implantable cardioverter-defibrillator was a powerful predictor of mortality for a subgroup of 134 patients with high-grade ventricular arrhythmias on Holter electrocardiography (mortality while on the waiting list: 26.1%; transplantation rate: 54.5%; p = 0.022) and for a subgroup of 58 survivors of sudden cardiac death (mortality while on the waiting list: 22.4%; transplantation rate: 56.9%; p = 0.018). Implantable cardioverter-defibrillator therapy can be strongly recommended in transplant candidates with a history of sudden cardiac death. Recommendations for an expanded, prophylactic use of implantable cardioverter-defibrillator therapy in heart transplant candidates cannot be given.

Arrhythmias, Cardiac↗
PubMed1995

[Strategies in management of heart transplantation candidates with tachycardic ventricular arrhythmia anamnesis].

We followed up 73 consecutive patients with a history of syncopal ventricular tachyarrhythmias on the waiting list for a heart transplant between 1st March 1992 and 15th September 1994 with the aim of evaluating the impact of implantable cardioverter defibrillator (ICD) on survival. On registration 60 patients were considered fit enough to be ambulant whilst awaiting transplantation. 30 were given ICD therapy (group 1) and 30 were not (group 2). 13 patients required inpatient supervision for ventricular arrhythmias whilst awaiting transplantation, but received no ICD therapy (group 3). The 13 in-patients were in a worse clinical state (NYHA) than the 30 out-patients not given ICD (p < 0.05). With respect to all other clinical and hemodynamic characteristics all groups were comparable. Waiting time for transplantation was also comparable in all groups (n.s., log-rank method). ICD therapy resulted in a significant improvement of survival in these high-risk patients prior to transplantation. Only 1 out of the 30 ICD patients (group 2) and 5 out of the 13 in-patients (group 3) (p < 0.05 log-rank method). During the waiting time group 3 patients were hospitalised longest (p < 0.05), but there was a clear trend that also ICD patients had to be hospitalised to an increased extent (n.s.). Cox multivariate regression analysis of this study population showed that the cardiac index (p = 0.001) and lack of ICD therapy (p = 0.035) were the only independent significant predictors of mortality on the waiting list. ICD therapy had no influence on mortality after transplantation (n.s. log-rank method).

Adult↗
PubMed1994

Adenosine for the management of patients with tachycardias--a new protocol.

We developed a new protocol for diagnosis and treatment of patients with sustained tachycardias (heart rate > 150 beats.min-1). The patients first underwent vagal manoeuvres; if those remained unsuccessful, i.v. adenosine in increasing doses of 6, 12, and 18 mg was administered until sinus rhythm (SR) or transient atrioventricular (AV) block, unmasking the underlying rhythm, was recorded. In the latter and in the non-responding cases other antiarrhythmics were applied. Ninety-three episodes of tachycardia in 46 patients were treated according to this protocol. Six episodes (6%) were terminated by carotid massage, 64 of the remaining 87 episodes (74%) responded to adenosine with return to SR. Conversion to SR occurred more often in episodes with narrow- than in wide-complex tachycardia (81 vs. 59%, P < 0.05). To achieve SR, the mean adenosine dose was lower in narrow- than in wide-complex tachycardia (13 +/- 8 vs 21 +/- 10 mg; P < 0.01). The duration of asystole after adenosine did not differ between these two groups, whereas the duration of arrhythmia after adenosine differed significantly (8.5 +/- 5.8 vs 18.6 +/- 22.9 s; P < 0.05). Side effects of adenosine such as flush, dyspnoea, and chest pain did not seem to be dose dependent and occurred in about 20%. According to our protocol, in more than 75% SR was achieved in patients with sustained tachycardias after vagal manoeuvres and adenosine.

Adenosine↗
PubMed1992

Cardiac involvement in systemic sclerosis.

OBJECTIVE: To assess the incidence and extent of cardiac involvement in systemic sclerosis (SSc) patients with no apparent cardiac symptoms. METHODS: Surface electrocardiography, ambulatory electrocardiography, radionuclide ventriculography, myocardial scintigraphy, and echocardiography were performed in 18 patients. RESULTS: These studies demonstrated ventricular tachycardia in 1 patient, nonsustained ventricular tachycardia in 5, supraventricular tachycardia in 6, decreased left ventricular ejection fraction in 2, decreased right ventricular ejection fraction in 8, and stress-induced reversible myocardial perfusion abnormalities in 6. CONCLUSION: These observations demonstrate a high rate of cardiac abnormalities in SSc patients without cardiac symptoms.

Aged↗
PubMed1992

Antiadrenergic cardiovascular adverse effects of high-dose amiodarone loading regimen.

A 55-year-old patient with inferior wall infarction was treated effectively for ventricular tachycardia with high-dose oral amiodarone loading regimen (5 g within 16 hours). Serial pharmacokinetic studies demonstrated a rapid temporary increase in amiodarone plasma concentration to a maximum of 3.40 micrograms/ml 17 hours after initiation of therapy followed by a return to normal plasma concentration within 8 hours. During fast drug evasion the patient developed acute low-output syndrome with syncope successfully controlled with intravenous catecholamine administration. Our findings suggest that the cardiovascular collapse was caused by the non-competitive adrenoceptor antagonism of amiodarone resulting in secondary autonomic insufficiency.

Administration, Oral↗
PubMed1992

Prognostic value of heart rate variability in patients awaiting cardiac transplantation.

Time and frequency domain parameters of heart rate variability (HRV) were determined in patients with severe endstage heart failure awaiting cardiac transplantation (HTX). These parameters were then correlated with mortality to investigate the performance of HRV in discriminating between groups with high and low risk of death. The standard deviation of five consecutive RR intervals (SDANN) was found to be the parameter with the greatest sensitivity (90%) and specificity (91%). Patients with SDANN values of < 55 msec had a twenty-fold increased risk of death (90% confidence limits: 4-118, P < 0.001). The results furthermore suggest that measurements of HRV are superior to other prognostic markers such as left ventricular ejection fraction, pulmonary artery wedge pressure, cardiac index, and serum sodium levels. We conclude that HRV is a powerful, noninvasive tool to assess the risk of death in candidates for HTX. HRV measurements can therefore be used as a supplement to other markers of risk to determine the optimal therapeutic strategy in patients with severe congestive heart failure.

Adult↗
PubMed1992

[Ventricular tachycardia and ventricular fibrillation. Diagnostic procedure for selection of patients for non-medicamentous therapeutic procedures].

The use of nonpharmacological methods in the treatment of life-threatening ventricular tachyarrhythmias is increasing. These include surgical procedures, the application of direct and radiofrequency current for endocardial ablation, antitachycardia stimulation techniques and the implantation of cardioverter defibrillators. Each of these therapeutical procedures is characterized by its specific indication. Based on the underlying cardiac disease and the characteristics of the electrophysiological properties of the ventricular tachyarrhythmia as well as based on the specific properties of the different nonpharmacological procedures an individual therapeutical approach has to be tailored for a patient given. Primary goal is application of a nonpharmacological procedure exclusively, however, in selected cases additional administration of an anti-arrhythmic drug (decrease in tachycardia frequency in patients with implanted defibrillators, widening of the termination window in patients with antitachycardia devices) may be necessary to achieve satisfactory tachycardia control.

Anti-Arrhythmia Agents↗
PubMed1991

Plasma propafenone concentration in the evaluation of anti-arrhythmic efficacy.

The anti-arrhythmic drug efficacy of oral propafenone therapy (300 mg to 900 mg per day) was studied in relation to propafenone and hydroxy-propafenone plasma concentrations in 70 outpatients (46 males, 24 females, mean age 57 +/- 12 years) followed up for 24 +/- 32 months. On average 1.7 plasma concentration measurements were performed per patient. The arrhythmias were effectively controlled in 32 patients, but in another 32 patients propafenone therapy was ineffective; in six patients the evaluation was unclear. The therapy was effective in 66% of patients with ventricular premature beats, in 50% with complex ventricular arrhythmias, in 40% with ventricular tachycardia and in 20% with supraventricular tachycardia. Fifty per cent of patients with coronary heart disease and electrical disease, but only 20% with dilated cardiomyopathy and Wolff-Parkinson-White syndrome were effectively treated. Measurement of peak plasma propafenone levels performed 4.5 +/- 2 h after oral drug administration revealed no statistically significant dose-plasma concentration relation. Optimal propafenone drug efficacy was documented at propafenone plasma concentrations ranging from 0.20 to 0.60 micrograms/ml (63% of patients considered as effectively treated). There was a trend to decrease propafenone efficacy at plasma concentrations below 0.20 micrograms/ml and above 0.60 micrograms/ml. Analysis of hydroxypropafenone identified four patients as poor metabolizers with unusually high propafenone and low hydroxypropafenone plasma concentrations; only one of these four patients showed drug efficacy. Monitoring of propafenone and hydroxypropafenone plasma concentrations was a practical procedure to assess patient's compliance, to identify poor metabolizers and to guide anti-arrhythmic drug therapy.

Adult↗
PubMed1991

Determinants of subsidiary ventricular pacemaker suppression in man.

To investigate the relative contribution of the duration and rate of overdrive to subsidiary ventricular pacemaker suppression, in six patients with complete heart block after His-bundle ablation, ventricular overdrive stimulation studies were performed. The studies, which were spread over a mean follow-up period of 745 days, were carried out invasively with a temporary lead (one patient) as well as noninvasively with the implanted pacemakers and chest wall inhibition (five patients). The overdrive pacing rate was increased in steps of 10 beats/min, and the pacing duration was 15, 30, 60, 90, and 120 seconds at each level. A recovery period of 2 minutes was allowed after each overdrive stimulation. Incremental ventricular overdrive stimulation at increasing pacing durations consistently caused progressive suppression of ventricular impulse formation. Nonparametric variance analysis demonstrated a significant (P less than 0.0001) influence of both the pacing rate and duration on ventricular recovery time. Nonlinear regression showed an exponential increase in recovery time with incremental pacing rate and a biphasic increase in recovery time with incremental pacing duration. Beyond a pacing duration of 60 seconds ventricular impulse suppression was primarily dependent upon the pacing rate. A nonlinear regression model was applied to predict the number of beats required for return of the escape rhythm toward prepacing control values. The predicted maximum mean number of beats was 15.4 +/- 5.9 and independent of the rate and duration of pacing, although, the initial temporary instability of the escape rhythm was directly related to the degree of overdrive.

Adult↗
PubMed1989

24 hours electrocardiographic monitoring in obese children and adolescents during a 3 weeks low calorie diet (500 kcal).

Twenty-four hour electrographic recordings were made on 36 grossly obese children and adolescents during a 3-week weight reduction regimen with a 525 kcal (2196 kj) mixed diet at weekly intervals. One hundred and ten Holter ECGs were analysed. Weight loss during the treatment was calculated to be 5.7 +/- 1.6 kg. Average and minimal heart rate decreased constantly throughout the study period from 83.9 +/- 9 to 75 +/- 9/min and 53 +/- 6 to 45 +/- 6/min, respectively (P less than 0.01, P less than 0.005). During the second week maximal heart rate increased significantly but returned to baseline values in the third week. Neither before nor during the period of therapy were any dysrhythmias monitored. Dietary regimens containing 500-700 kcal, based on a mixed composition of foods with sufficient amounts of minerals, can be regarded as a safe therapeutic tool in the treatment of obese children and adolescents.

Adolescent↗
PubMed1988

[Value of computer-assisted, digital long-term ECG analysis in clinical routine practice].

At present the Holter method (HM) is a frequently used investigational procedure in the clinical routine. It was the aim of a prospective study to evaluate the HM from the user's point of view. Therefore a questionnaire was attached to each analysis report including two main questions, which should be answered by the referring physician: Does the analysis result fulfill the consumer's needs? What consequences are drawn due to the HM results? Among 675 questionnaires returned to the laboratory 75% of the referring physicians felt satisfied by the HM result. Disappointments were predominantly related to too infrequently occurring episodes, which did not appear during one 24-hour recording period. Evaluation of therapy (89%), recording prior to antiarrhythmic therapy (84%) and quantification of well-known arrhythmias were the most successful indications of HM. The tremendous daily variability of infrequent symptoms or arrhythmias were the main causes for unsatisfactory results. A successful HM led predominantly to therapeutic consequences (begin, continuation, change or withdrawal of anti-arrhythmic drugs). In 25% HM was not followed by further therapeutic or diagnostic consequences, so that the indication for the HM should be reevaluated! Diagnostic consequences included repeated HM, ECG-Telephone-Transmission consequences heart catheterisation or electrophysiological procedures. In summary the Holter method satisfies the physician's demands if the expectations do not exceed the limitations of the method.

Adolescent↗
PubMed1988

[Variability of arrhythmias and symptoms--their effect on long-term ECG analysis].

The variability of variables influences conclusions in the measurement of biologic variables particularly if the variability of methodological variables are unidentified or of unknown range. Therefore prior the interpretation of Holter-results the interobserver variability of measured parameters (e. g. arrhythmias) and the system-dependent variables (e. g. reproducibility) have to be recognized. Measuring biologic variables like arrhythmias or symptoms using the Holter method the spontaneous variability of infrequent occurring phenomena has to be taken into account and also their relationship to the recording duration: Infrequent occurring phenomena demonstrate an enormous variability, which could be reduced by lengthening the recording duration beyond 24 hours, especially in the evaluation of an antiarrhythmic therapy to avoid a mimicked therapeutic effect. In symptomatic patients their symptoms can be related to arrhythmias or not if an ECG will be recorded during a typical symptomatic period. This depends on the frequency and on the duration of the symptoms, so that other methods than Holter-monitoring should be considered like event-recording, ECG-telephone-telemetry or electrophysiological investigations. In summary the variability of phenomena captured by the Holter method (e. g. arrhythmias, symptoms) is a major factor, which has to be taken into account to avoid unsatisfactorial use of the Holter method.

Anti-Arrhythmia Agents↗
PubMed1988

The influence of nitroglycerine on the inducibility of sustained ventricular tachycardia in coronary artery disease.

To investigate the influence of nitroglycerine on the inducibility of sustained ventricular tachycardia, 11 patients with documented sustained ventricular tachycardia were studied (mean age 59 years, range 52-70 years, eight posterior wall infarctions, three anterior wall infarctions). After the induction of sustained ventricular tachycardia using a standard protocol (three ventricular premature beats triggered on the R wave, three ventricular premature beats to the refractory period during basic driving rate up to 180 beats min-1), 0.8 mg nitroglycerine was given and when the wedge pressure started dropping (after about 3 min) the EPS was repeated. The mode of the initiation of sustained ventricular tachycardia was almost identical before and after application of nitroglycerine. In addition the heart rate before (mean 186 beats min-1) and after nitroglycerine (mean 187 beats min-1) and the morphology of sustained ventricular tachycardia were the same. It is therefore concluded that anti-ischaemic interventions by nitroglycerine treating silent ischaemia and improving ventricular function respectively does not influence the initiation of sustained ventricular tachycardia during EPS. Silent ischaemia obviously does not play a role in sustained ventricular tachycardia and therefore anti-ischaemic interventions cannot be expected to influence the recurrence of sustained ventricular tachycardia.

Aged↗
PubMed1988

Survival rate and causes of death in patients with pacemakers: dependence on symptoms leading to pacemaker implantation.

The survival rate of 2256 patients with pacemakers was analyzed. Patients paced for Adams-Stokes equivalents (e.g. dizziness) showed a significantly better survival rate than did patients with pacemakers implanted for Adam-Stokes attacks or heart failure (P less than 0.0001). The estimated survival of the latter two groups did not differ significantly. Of the deceased patients who had received a pacemaker for the treatment of heart failure, 54% died due to this condition despite pacemaker implantation. The relative percentage of cases of sudden death after pacemaker implantation was high in the groups with Adams-Stokes attacks (12%) and Adams-Stokes equivalents (13%). In patients paced for Adams-Stokes attacks, sudden death occurred more frequently in the first year after pacemaker implantation (P less than 0.015) than during the following years. Therefore, increased efforts should be made to monitor patients carefully after pacemaker implantation to enable prompt detection of malignant tachyarrhythmias, probably the cause of sudden death in a substantial number of patients with pacemakers.

Adams-Stokes Syndrome↗
PubMed1988

Physiological variation in the termination window of re-entry tachycardia studied by non-invasive programmed stimulation.

In seven patients with re-entry tachycardias and the implanted antitachycardia device Tachylog (Siemens Elema, Sweden) the variation in the termination window related to posture and exertion was investigated. The investigations were performed on an outpatient basis utilizing the interactive pacing mode of the implanted unit. Six patients had supraventricular tachycardia and one patient had exercise-induced ventricular tachycardia. In all patients, double ventricular stimuli were necessary for tachycardia control. In the patients with supraventricular tachycardia, the termination window decreased significantly in the erect position (-46.5%, P less than 0.001) and in two patients it completely disappeared. Two patients could be studied during exercise. In one patient, exertion caused the termination window to shrink to 63% of its duration standing still, whereas in the other patient it widened to twice its value in the erect position. In the patient with ventricular tachycardia, whom we could study erect only, additional exercise caused the termination window to shrink on average 16.5%. These findings demonstrate that the termination window of re-entry tachycardia varies considerably with posture and exercise. This has important implications for the design of antitachycardia algorithms which will be reliably effective during daily life. Repeated non-invasive stimulation studies can be performed as an outpatient procedure allowing investigation of re-entry tachycardia under circumstances mimicking daily life.

Adolescent↗
PubMed1988

Rate dependent depression of subsidiary ventricular impulse formation--cause of Stokes-Adams attacks in a patient with rate modulated pacing.

Following His bundle ablation and implantation of a rate adaptive pacemaker (Vitatron TX 911) a 52-year-old gentleman experienced several presyncopal attacks while driving a car. On examination pectoralis muscle contraction caused temporary pacemaker inhibition. Incremental overdrive stimulation demonstrated progressive depression idioventricular automaticity and was associated with similar symptoms following overdrive at high pacing rates. Following appropriate pacemaker programming the patient remained symptom free.

Adams-Stokes Syndrome↗