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T Lewalter

Publications and source records attributed to T Lewalter.

At least 19 recordsLinked to original sources
PubMed2006

[Pharmacotherapy of supraventricular arrhythmias. What comes, what remains, what goes?].

Supraventricular tachycardias consist of AV-nodal-reentrant-tachycardias, atrioventricular tachycardias with accessory pathways (WPW-syndrome), atrial tachycardias, atrial fibrillation and atrial flutter. Only specific ECG interpretation with an exact arrhythmia classification offers the way to perform modern differential therapy including drug treatment and also interventional therapy modalities. In atrial fibrillation, drug treatment is still first-line therapy: physicians have to make a decision either to follow the rate or rhythm control concept. In case of rhythm control, drug therapy is tailored to the individual patient taking into account the patients symptomatology, left ventricular ejection fraction and nature and degree of an underlying cardiac disease. Drug refractory symptomatic atrial fibrillation patients should be considered for interventional treatment like pulmonary vein ablation. Recurrent typical right atrial flutter, AV-nodal-reentrant-tachycardia and all forms of atrioventricular tachycardias however are indications for catheter ablation; long-term drug treatment will only be performed in rare cases.

Anti-Arrhythmia Agents↗
PubMed2006

[Ventricular tachycardia. Diagnostic spectrum and therapeutic measures].

The origin of ventricular tachycardia lies in the ventricular tissue and includes a variety of symptoms such as monomorphic and polymorphic ventricular tachyarrhythmia (VT), ventricular flutter and ventricular fibrillation. Due to transitions of one form of VT to another, any form of VT incurs in principal the risk of cardiac failure. Apart from different electrophysiologic mechanisms such as reentry or triggered activity, any occurrence of VT has to be considered in an individual context: VT can be caused by structural heart disease such as coronary artery disease or dilative cardiomyopathy, or primary electrical disease such as long or short QT syndromes or can even occur without any detectable cause (idiopathic VT). Correct identification of the underlying cause of the arrhythmia is essential for the prognosis, differential therapy and long-term treatment of patients.

Catheter Ablation↗
PubMed2006

[Electrical and pharmacological strategies for early cardioversion of atrial fibrillation].

Cardioversion of atrial fibrillation as an element of rhythm control strategy is indicated in patients with first episode of atrial fibrillation, hemodynamic instability, recurrent atrial fibrillation with low probability of spontaneous conversion, or severe symptoms. Early cardioversion is performed within 48 h of onset of atrial fibrillation. The best point in time is still unknown. It can be performed by pharmacological, or, preferentially, by electrical cardioversion. The advantages of electrical cardioversion are higher efficacy and no proarrhythmic risk, however, short time general anaesthesia is needed. Electrical cardioversion is most effective when biphasic shocks are delivered. For pharmacological cardioversion, several antiarrhythmic drugs are available which have to be considered individually. Thromboembolic risk does not differ between the two methods. Early cardioversion and maintenance of sinus rhythm is most effective in atrial fibrillation of short duration, normal left atrial size and no or only mild structural heart disease.

Anti-Arrhythmia Agents↗
PubMed2005

Influence of obstructive sleep apnea on heart rate turbulence.

BACKGROUND: Patients with obstructive sleep apnea (OSA) are at increased risk for cardiovascular disease. Increased sympathetic drive is considered as one of the underlying mechanisms. Both heart rate turbulence (HRT) and heart rate variability (HRV) are parameters to describe autonomic regulation. We investigated the influence of sleep-disordered breathing (SDB) on HRT and HRV in patients with OSA. METHODS: Sixty-five patients underwent overnight polysomnography for clinically suspected SDB and simultaneous Holter monitoring (11 p.m.-6 a.m.). Patients with diabetes mellitus, a history of cardiac disease, left ventricular dysfunction, periodic breathing pattern, and those on beta-blockers or theophylline were excluded. According to the apnea-hypopnea index (AHI), the patients were assigned to group A (AHI <20, n = 31) or group B (AHI > or =20, n = 34). HRV (time domain, frequency domain) and HRT (onset, slope) were then related to the severity of SDB. RESULTS: Nighttime turbulence slope (TS) correlated inversely with the AHI (r = -0.45, p = 0.01) and was significantly lower in group B (8.9 +/- 1.6 ms/R-R interval) compared with that in group A (19.8 +/- 4.0 ms/R-R interval, P = 0.01). This relationship remained stable after adjusting TS for the number of ventricular premature contractions. No significant differences in turbulence onset or parameters of nighttime HRV were observed. CONCLUSIONS: Alterations in nighttime HRT correlate with the severity of SDB, indicating abnormalities in cardiac autonomic activity in moderate-to-severe OSA even in the absence of overt cardiac disease. These changes may be associated with the subsequent development of cardiovascular disease.

Adult↗
PubMed2005

Atrial fibrillation: profit from cardiac pacing?

The impact of cardiac pacing on the prevention of atrial fibrillation is under scientific investigation. Several prospective randomised clinical trials have reported that atrial-based "physiologic" AAI(R)- or DDD(R)-pacing is associated with a lower incidence of paroxysmal and permanent atrial fibrillation than single-chamber ventricular pacing in patients with a conventional pacemaker indication. However, it is still uncertain whether atrial pacing itself has independent antiarrhythmic properties. In contrast, right ventricular pacing is considered to promote atrial fibrillation, even in preserved AV synchrony during dual-chamber pacing. The electrical secondary prevention of atrial fibrillation is mainly based on variations of the atrial pacing site and sophisticated preventive pacing algorithms incorporated in the pacemaker software. Dual-site right atrial and biatrial pacing were reported to exhibit modest to no benefit for the prevention of atrial fibrillation, whereas septal pacing and specific preventive pacing algorithms have been demonstrated to reduce the incidence of atrial fibrillation in a number of clinical trials. However, the role of septal pacing and preventive pacing algorithms still has to be clarified since, overall, study results have been inconsistent so far. One of the main goals of future investigations should be the identification of responder groups of preventive pacing concepts. In clinical practice, the efficacy of pacing algorithms and septal pacing has to be determined in the individual case. These options should be taken into account in patients with symptomatic bradycardia as the indication for cardiac pacing and, in addition, symptomatic atrial fibrillation.

Atrial Fibrillation↗
PubMed2005

Pharmacological and ablative hybrid therapy of atrial fibrillation. Long-term effect on quality of life and arrhythmia-related symptoms.

UNLABELLED: The pharmacological and ablative hybrid therapy of atrial fibrillation (AF) consists of radiofrequency catheter ablation of antiarrhythmic drug-induced typical atrial flutter (AFl) and continuation of drug therapy. The purpose of this study was to determine the effect of this therapy on AF symptoms and quality of life (QoL). Forty-six patients were monitored after isthmus-ablation of drug-induced typical AFl and continuation of their antiarrhythmic drug treatment over a mean follow-up of 22.4+/-11.6 months. AF characteristics, symptoms and QoL before and after ablation were evaluated by the SF-36 question- naire, the Symptoms Checklist-Frequency and Severity Scale and the analysis of ECG recordings. 63% of patients demonstrated recurrences of AF. However, the frequency and duration of symptomatic episodes significantly decreased in 82.6 and 76% of patients. All categories of the SF-36 improved significantly and the AF symptomatology showed a relevant attenuation in 65.8% of the study population. CONCLUSION: The pharmacological and ablative hybrid therapy significantly reduced the mean number and the duration of symptomatic AF episodes as well as AF-correlated symptoms and was associated with significant QoL improvement.

Anti-Arrhythmia Agents↗
PubMed2004

Mayer-von Rokitansky-Küster-Hauser syndrome in association with a hitherto undescribed variant of the Holt-Oram syndrome with an aorto-pulmonary window.

We report on the association of Mayer-von Rokitansky-Küster-Hauser syndrome (MRKHS) with a unique form of Holt-Oram syndrome (HOS) with an aorto-pulmonary window. A 24-year-old Turkish woman was referred to our hospital because of primary amenorrhoea. Both her vagina and uterus were absent, and the diagnosis of MRKHS was established. Laparoscopic creation of a neovagina by the modified Vecchietti technique was performed. A rare congenital malformation of the heart, namely an aorto-pulmonary window, had required cardiac surgery when the patient was a 6-month-old infant. This cardiac malformation plus associated upper limb anomalies led to the clinical diagnosis of HOS. To the best of our knowledge, this is only the second report in the scientific literature on the concurrence of MRKHS and HOS, and the first published case of HOS with an aorto-pulmonary window as the cardiac malformation.

Abnormalities, Multiple↗
PubMed2004

Heart rate variability in patients suffering from structural heart disease and decreased AV-nodal conduction capacity. Insights into the formation of heart rate variability.

METHODS: Time and frequency domain analysis were conducted during a period of 600 s each. We performed a special protocol consisting of five different "pacing" periods: 1) recording of normal sinus rhythm (SR1); 2) atrial pacing with a rate 15% higher than the intrinsic heart rate; 3) ventricular pacing triggered by atrial activation (VAT, with a short AV-delay of 80 ms); 4) AV-sequential pacing with an atrial rate 15% higher than the intrinsic heart rate and a very short AV delay of 80 ms (DDD); 5) normal sinus rhythm (SR2). Only patients with normal AV-nodal conduction or with AV-block I degrees were included. The influence of a structural heart disease as well as a non-sustained VT on Holter ECG and a depressed EF on HRV parameters were analyzed using a multivariate analysis. All patients were lying in a supine position. Blood pressure was measured continuously and the frequency of breathing was controlled. RESULTS: No differences in HRV between the two sinus rhythm periods SR1 versus SR2 could be detected. Neither SR1 vs VAT showed a significant difference for SDNN and r-MSSD. In contrast, HRV during SR1 compared to AAI, and HRV during VAT compared to AAI were significantly different (p < 0.001). When comparing HRV during DDD, which should be zero, and AAI, we found a significantly lower SDNN and r-MSSD (1.2 ms vs 4 ms, p < 0.04). The presence of structural heart disease, a non-sustained ventricular tachycardia, a depressed ejection fraction of less than 0.50 did not reveal a significant influence on the HRV parameters (multivariate analysis). The mean Wenckebach in patients with structural heart disease tended to be greater (437 ms vs 350 ms, p = 0.05); an increase in the Wenckebach was not correlated to a change in HRV parameters (p = ns). CONCLUSION: Heart rate variability derived from consecutive RR-intervals is predominantly caused by periodicity in sinus-node impulse formation. A conduction variability of the AV-node exists, but is very low. The presence of a structural heart disease, a non-sustained ventricular tachycardia on Holter ECG, as well as a depressed ejection fraction of less than 0.50 showed no significant influence on the HRV parameters. Therefore, one can apply the calculation of heart rate variability for risk stratification in patients suffering from structural heart disease and moderate AV-nodal conduction disturbances. Attenuation of the oscillation of the heart rate, i. e. heart rate variability (HRV), is associated with an increased risk for mortality in patients with structural heart disease. Many of these patients also suffer from conduction disturbances, e. g. AV-nodal conduction delays. Whether the calculation of HRV in those patients is recommendable has not been investigated yet. Therefore, we conducted a study consisting of 20 consecutive patients in order to determine the formation of HRV, the influence of structural heart disease, the presence of a nonsustained ventricular tachycardia (VT), and a reduced ejection fraction (EF) on the HRV parameters during an elective electrophysiologic study.

Adult↗
PubMed2003

[Atypical resting ecg pattern in a patient with a positive family history of sudden cardiac death]].

A 42 year old male patient presented with atypical ECG pattern at rest and reported that his brother died suddenly of unknown reasons at the age of 40. A performed pharmacological testing with ajmalin discovered strong ST-segment elevations in lead V(1) and V(2) in combination with an incomplete right bundle branch block. As a result, the diagnosis Brugada syndrome was established. The Brugada syndrome is a primary cardiac conduction disturbance without structural heart disease and is associated with an increased risk of sudden cardiac death caused by life threatening ventricular tachyarrhythmia. It is an inherited disease displaying an autosomal dominant mode of transmission with an incomplete penetrance, especially prevalent in females. In some regions like the southeast of Asia and Japan it is endemic. The mutation is linked to the sodium channel gene SCN5A. The annual mortality rate is estimated 30 per 100.000 persons. Today, exact diagnostic criteria do not exist. The diagnosis is based on the typical ECG pattern, combined with clinical symptoms, and a family history of sudden cardiac death. The currently suggested therapy consists of the implantation of an internal defibrillator.

Adult↗
PubMed2003

Amiodarone-associated "torsade de pointes". Relevance of concomitant cardiovascular medication in a patient with atrial fibrillation and structural heart disease.

A 69 year old female with history of coronary heart disease, myocardial infarction and paroxysmal atrial fibrillation suffered from occipital apoplexy. Under treatment with amiodarone 600 mg daily and concomitant medication with beta-acetyldigoxine (0.1 mg daily) and bisoprolole (1.25 mg daily), significant QT-prolongation (max. 700 ms; QTc: 614 ms) could be documented. Out of normofrequent sinus rhythm but as well out of bradycardia, the patient developed repetitive short-lasting "torsade de pointes" tachycardias (320 bpm) which terminated spontaneously. Serum electrolytes, plasma levels of digoxine (1.76 ng/ml) and amiodarone (1.9 mcg/ml) were within therapeutic range. This case report is the first to describe induction of amiodarone-associated "torsade de pointes" tachycardia during concomitant beta-blocker and digitalis medication in a patient with atrial fibrillation and structural heart disease. This points towards an elevated risk for proarrhythmia under this triple therapy.

Acetyldigoxins↗
PubMed2002

[Cardiac resynchronization therapy by biventricular pacing. How many patients with left ventricular dysfunction are eligible?].

BACKGROUND AND OBJECTIVE: Cardiac resynchronization therapy by multisite biventricular pacing presents an additive therapeutic option in the treatment of severe congestive heart failure. The objective of the study was to evaluate how many patients with left ventricular dysfunction may potentially benefit from this therapy. METHODS: A total of 975 patients were screened for the prevalence of left ventricular dysfunction. Patients with a left ventricular ejection fraction (LVEF) <45 % were included into the investigation. Potential benefit of biventricular pacing was presumed in the presence of: LVEF < 35 %, severe heart failure (NHYA class III or IV), intrinsic left bundle branch block pattern with QRS interval > 150 ms and the absence of atrial fibrillation in the last 3 months before study inclusion. RESULTS: In 203 patients (168 male, 35 female, mean age: 64 +/- 11) an LVEF <45 % was found. A total of 12 of these patients (6 %) or 12 of 113 patients (11 %) with an LVEF <35 % were identified as appropiate candidates for biventricular resynchronization therapy. CONCLUSIONS: Cardiac biventricular pacing currently serves as a therapeutic option for a relatively small subgroup of patients with left ventricular dysfunction. Focusing on estimations that the incidence of heart failure in Germany amounts to more than 100.000 cases per year our results suggest that after all more than 6.000 patients per year may potentially benefit from electric resynchronization therapy. This number may increase substantially if prospective studies can prove that patients with heart failure and atrial fibrillation or left ventricular conduction delay due to univentricular pacing also benefit from cardiac resynchronization therapy.

Aged↗
PubMed2002

Decremental intravenous pulse propagation during extrastimulus pacing: relevance for catheter ablation of focal atrial fibrillation.

We report a case study demonstrating delayed circumferential intrapulmonary-venous conduction characteristics during coronary sinus extrastimulus pacing. This phenomenon allowed the unmasking and discrimination of a localized left atrial to PV breakthrough from secondarily activated PV muscle in a common left-sided PV ostium. Thus, this pacing manoeuvre may serve to guide RF delivery in the treatment of focal AF.

Atrial Fibrillation↗
PubMed2001

Prevalence of left atrial chamber and appendage thrombi in patients with atrial flutter and its clinical significance.

OBJECTIVES: The study was done to assess the prevalence of left atrial (LA) chamber and appendage thrombi in patients with atrial flutter (AFl) scheduled for electrophysiologic study (EPS), to evaluate the prevalence of thromboembolic complications after transesophageal echocardiographic (TEE)-guided restoration of sinus rhythm and to evaluate clinical risk factors for a thrombogenic milieu. BACKGROUND: Recent studies showed controversial results on the prevalence of atrial thrombi and the risk of thromboembolism after restoring sinus rhythm in patients with AFl. METHODS: Between 1995 and 1999, patients with AFl who were scheduled for EPS were included in the study. After transesophageal assessment of the left atrial appendage and exclusion of thrombi, an effective anticoagulation was initiated and patients underwent EPS within 24 h. RESULTS: We performed 202 EPSs (radiofrequency catheter ablation, n = 122; overdrive stimulation, n = 64; electrical cardioversion, n = 16) in 139 consecutive patients with AFl. Fifteen patients with a thrombogenic milieu were identified. All of them had paroxysmal atrial fibrillation (AF). Transesophageal echocardiography revealed LA thrombi in two cases (1%). After EPS no thromboembolic complications were observed. Diabetes mellitus, arterial hypertension and a decreased left ventricular ejection fraction were found to be independent risk factors associated with a thrombogenic milieu. CONCLUSIONS: The findings of a low prevalence of LA appendage thrombi (1%) in patients with AFl and a close correlation between a history of previous embolism and paroxysmal AF support the current guidelines that patients with pure AFl do not require anticoagulation therapy, whereas patients with AFl and paroxysmal AF should receive anticoagulation therapy. In addition, the presence of clinical risk factors should alert the physician to an increased likelihood for a thrombogenic milieu.

Aged↗
PubMed2001

Interference with cardiac pacemakers by magnetic resonance imaging: are there irreversible changes at 0.5 Tesla?

The safety and feasibility of magnetic resonance imaging (MRI) in patients with cardiac pacemakers is an issue of gaining significance. The effect of MRI on patients' pacemaker systems has only been analyzed retrospectively in some case reports. Therefore, this study prospectively investigated if MRI causes irreversible changes in patients' pacemaker systems. The effect of MRI at 0.5 Tesla on sensing and stimulation thresholds, lead impedance and battery voltage, current, and impedance was estimated during 34 MRI examinations in 32 patients with implanted pacemakers. After measurements at baseline and with documentation of intrinsic rhythm and modification of the pacing mode, patients underwent MRI. The rest of the function time of the pacemaker was calculated. Measurements were again performed after 99.5 +/- 29.6 minutes (mean +/- SD), immediately after MRI examination, and 3 months later. Lead impedance and sensing and stimulation thresholds did not change after MRI. Battery voltage decreased immediately after MRI and recovered 3 months later. Battery current and impedance tended to increase. The calculated rest of function time did not change immediately after MRI. MRI affected neither pacemaker programmed data, nor the ability to interrogate, program, or use telemetry. Surprisingly, in the gantry of the scanner, temporary deactivation of the reed switch occurred in 12 of 32 patients when positioned in the center of the magnetic field. Missing activation of the reed switch through the static magnetic field at 0.5 Tesla is not unusual. MRI at 0.5 Tesla does not cause irreversible changes in patients' pacemaker systems.

Contraindications↗