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Biomedical subjects

G Breithardt

Publications and source records attributed to G Breithardt.

At least 415 records · Page 23Linked to original sources
PubMed1987

[Possibilities and limitations of catheter ablation of tachycardia arrhythmia].

Catheter ablation has become an alternative to other non-pharmacological forms of antiarrhythmic therapy. Since supraventricular arrhythmias were first treated by ablation of the AV-conduction system, the clinical use of the technique has recently been extended to treat accessory pathways or ventricular tachycardias. The results of experiences from a number of clinical centers are available. To improve clinical applicability and to avoid complications, besides direct-current ablation, new technologies have been tested experimentally and in some cases already applied to patients. Whereas catheter ablation with radio-frequency alternating current has already been used in patients, the application of laser technology to ablation of arrhythmogenic myocardium has been limited to open heart surgery. Both techniques may offer improvements regarding precision and safety aspects of the method. To perform catheter ablation, a multitude of prerequisites concerning organisatory and safety aspects has to be fulfilled. Thus far, catheter ablation should only be performed in clinical centers with the facilities for cardiac surgery.

Cardiac Catheterization↗
PubMed1987

[Surgical treatment of patients with Wolff-Parkinson-White syndrome].

Patients with supraventricular reciprocating tachycardias or atrial fibrillation with rapid ventricular response mediated over an accessory pathway may be difficult to treat. In cases of medically refractory arrhythmias, or in patients requiring operations for other cardiac abnormalities, surgical division of an accessory pathway was attempted in 18 consecutive patients. The major indication for operation was drug refractory tachyarrhythmias in 13 patients, whereas 5 patients were operated upon primarily because of either aortic or mitral or tricuspid valve replacement. After careful preoperative and intraoperative electrophysiological evaluation, all patients revealed only one bypass tract. The location of the accessory pathways were as follows: 16 left free-wall and 2 right free-wall. Surgical division was attempted using the "Sealy-Technique". 14 accessory pathways were divided successfully and in 2 patients they were made responsive to previous ineffective medical therapy. In one patient operation was unsuccessful. In 3 patients reoperations were necessary because of the reappearance of accessory pathway conduction. One patient with associated Ebstein's anomaly died intraoperatively. During a follow-up of 26 +/- 21 months, 14 patients were free of tachyarrhythmias without antiarrhythmic medication, whereas 2 patients responded to previously ineffective therapy. Another patient undergoing unsuccessful surgical ablation was treated with amiodarone. These results indicate that by employing the Sealy-Technique accessory pathways could be successfully divided in 14 of 18 patients (78%) and additionally made responsive to previously ineffective antiarrhythmic therapy in 2 patients (11%) (total success = 89%).

Adolescent↗
PubMed1987

[Initial experiences with high-frequency electric ablation of the AV conduction system in the human].

For the first time, radiofrequency alternating current ablation of the AV-conduction system was performed in a 49-year-old female patient with recurrent atrial tachycardia with fast atrioventricular conduction, refractory to medical therapy, and two conventional DC-shock catheter ablation procedures. Without underlying cardiac disease, the patient had experienced almost daily episodes of tachycardia with a total of 10 syncopes. An electrophysiological study had revealed an ectopic right-atrial tachycardia and fast AV conduction up to a rate of more than 180 bpm. Soon after conventional right atrial catheter ablation, tachycardia with normal AV-conduction had recurred. Therefore, after catheter positioning (Lumelec, Cordis) at the proximal His bundle, 5 alternating current high-frequency pulses with an output energy of up to 50 W were applied under general anaesthesia. After the fourth application, the ECG revealed IIIrd degree AV-block with a His-bundle escape rhythm of 50 bpm. No complications occurred. Subsequent echocardiography did not reveal any pathological changes. The patient was put on anticoagulant therapy for the following 3 months and discharged after implantation of a permanent, activity-controlled pacemaker system (Activitrax, Medtronic). AV-block was persistent within a follow-up period of 3 months.

Bundle of His↗
PubMed1987

[Importance of programmed ventricular stimulation in patients with ventricular salvos].

The yield of programmed ventricular stimulation in asymptomatic patients with documented ventricular salvoes is not definitely known. Therefore, we retrospectively evaluated the data of 57 patients in whom ventricular salvoes had been observed, either during resting ECG or 24-hour ECG monitoring, and who had been studied using programmed ventricular stimulation. Of these patients, 63% were male, with a mean age of 49 years. 28% had coronary artery disease, 21% dilated cardiomyopathy, 16% mitral valve prolapse, 9% hypertrophic cardiomyopathy, 9% valvular heart disease and 14% had no structural heart disease. Using a maximum of two premature ventricular extrastimuli during programmed ventricular stimulation, sustained ventricular tachycardia or ventricular fibrillation was induced in nine patients (16%). In 30 patients (53%) nonsustained ventricular tachycardia was induced (3-35 ventricular echo beats), in 18 patients only one to two ventricular echo beats could be induced. In 8/16 patients (50%) with coronary artery disease, sustained ventricular tachycardia/ventricular fibrillation could be induced. Mean left ventricular ejection fraction did not differ between patients with inducible sustained ventricular tachyarrhythmia and those with inducible non-sustained ventricular tachycardia or those with a normal result during programmed ventricular stimulation. 33 patients were treated with antiarrhythmic drugs; the efficacy of antiarrhythmic therapy was either controlled by "serial electrophysiologic testing" in four patients, or by repeated 24-hour long-term ECG in 29 patients. During a mean follow-up period of 31 +/- 24 months five patients died, two of them suddenly. None of the remaining patients had experienced a symptomatic sustained ventricular tachycardia or a syncope.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Direct operations for the management of life-threatening ischemic ventricular tachycardia.

UNLABELLED: Between June 1978 and 1986, 93 consecutive patients underwent electrophysiologically guided operations for life-threatening recurrent sustained ventricular tachycardia mostly associated with other surgical procedures, such as left ventricular resection (aneurysmectomy) and coronary artery bypass grafting. DATA: Eighty-seven percent of the surviving patients were free of spontaneous ventricular tachycardia return or sudden death 1 year after the operation and 77% at 5 years. The instantaneous risk of ventricular tachycardia return was highest immediately after operation, declined rapidly, and by 2 weeks postoperatively had merged with the constant hazard phase, which persisted as long as the patients were observed. Endocardial resection, rather than encircling endocardial myotomy, increased the risk of spontaneous ventricular tachycardia return/sudden death. Survival rates, including hospital deaths, were 95% at 30 days, 89% at 1 year, and 70% at 5 years after operation. The most prevalent mode of death was heart failure. The absence of anterolateral left ventricular aneurysms and the use of more extended encircling incisional techniques for ventricular tachycardia ablation increased the risk of early and late death. Survival was particularly poor in that subset of patients in whom recurrent sustained ventricular tachycardia returned after operation; the most prevalent mode of death in this group was also progressive left ventricular failure. Inferences: (1) Complete and partial encircling endocardial myotomy incisions are the most effective surgical techniques for malignant ventricular tachycardia ablation. (2) Because of their adverse effects on left ventricular structure and function, the arrhythmogenic tissues have to be localized as precisely as possible, and the encompassing incisions should be kept as limited as possible. (3) The late return of ventricular tachycardia may be more related to a progressive ischemic left ventricular cardiomyopathy than to an inadequate operation.

Cardiac Pacing, Artificial↗
PubMed1986

Ectopic atrial tachycardia after transvenous catheter ablation of a posteroseptal accessory pathway.

Closed chest electrode catheter ablation of a posteroseptal accessory pathway was performed on an 18 year old patient with recurrent supraventricular tachycardia. After the procedure, ectopic atrial tachycardia was observed for the first time. Detailed endocardial atrial mapping revealed that this ectopic atrial tachycardia originated from the first site of catheter ablation. As retrograde conduction resumed, a second ablation procedure was performed, resulting in successful ablation of both the ectopic atrial tachycardia and the accessory pathway conduction.

Adolescent↗
PubMed1986

Methods for non-invasive detection of ventricular late potentials--a comparative multicenter study.

To evaluate the methodological problems of the non-invasive registration of late potentials the results obtained with four different averaging devices in the same 109 patients were compared. The high-resolution ECG was obtained from the body surface, high-gain amplified and filtered. With the averaging technique, the improved signal-to-noise ratio was able to detect low-amplitude cardiac activity. The incidence of late potentials detected with the four averaging systems, whose characteristics are described, ranged between 12% and 21%. Corresponding positive results were obtained in 5.5%, corresponding negative results in 68.8%. The reasons for differing results were mainly due to differences in visual or automatic interpretation of the registered fractionated electrical cardiac activity. Additionally, the determination of the end of QRS using the QRS width, obtained from reference leads, may influence the specificity of the methods.

Cardiac Complexes, Premature↗
PubMed1986

Predictive value of electrophysiologic testing in the treatment of drug-refractory ventricular arrhythmias with amiodarone.

The value of serial electrophysiologic testing in predicting the outcome of patients receiving amiodarone is controversial. Thirty-six patients with drug-refractory sustained ventricular tachyarrhythmias underwent serial electrophysiologic drug testing. All patients had inducible sustained ventricular tachyarrhythmias off any antiarrhythmic medication. After an oral amiodarone loading regimen there was no change in inducibility in 23 patients (group I), whereas ventricular tachycardia was made more difficult to induce in 5 patients, i.e. sustained ventricular tachycardia was only inducible using a basic drive which was 40 bpm faster than during control (group II). In the remaining 8 patients, induction of ventricular tachycardia was suppressed (group III). During follow-up of 11 +/- 12.3 months, 6 patients in group I had a recurrence of ventricular tachycardia and 2 died suddenly, whereas the course of groups II and III patients was uneventful (P less than 0.03, Breslow; P less than 0.01, Mantel-Cox). The predictive accuracy of the response to serial electrophysiologic testing during amiodarone therapy was 64%, the sensitivity was 46% and the specificity 100%. Thus, serial electrophysiologic drug testing is useful in determining prognosis and predicts the long-term response to amiodarone therapy in patients with ventricular tachyarrhythmias using a graded stimulation protocol.

Amiodarone↗
PubMed1986

[Graded criteria to assess the effectiveness of anti-arrhythmia therapy in patients with ventricular tachyarrhythmia by serial electrophysiological testing].

To test whether rendering ventricular tachycardia more difficult to induce during antiarrhythmic therapy can be considered as sufficient to predict long-term efficacy in patients with ventricular tachyarrhythmias, 95 patients were studied using a graded stimulation protocol (single and double premature stimuli during sinus rhythm and ventricular drive of 120, 140, 160 and 180 b.p.m.). After control, the effects of oral antiarrhythmic drugs on the ability to induce ventricular tachycardia were assessed. Median number of drug trials was 4 per patient. Following antiarrhythmic therapy 4 subgroups of patients were identified. In 36 patients there was no change in inducibility (group 1), whereas in 18 patients ventricular tachycardia was made more difficult to induce, i.e. a sustained ventricular tachycardia was inducible at a basic drive at least 40 b.p.m. faster than control (group 2). In 34 patients, ventricular tachycardia induction was suppressed (group 3) and in 7 patients with non-sustained ventricular tachycardia only 3 to 7 beats were induced after treatment (group 4). During follow-up of 12 +/- 11.2 months 10 patients of group 1 had a recurrence of ventricular tachycardia and 6 died suddenly, whereas in group 2 only one patient died suddenly and in group 3 2 patients had a recurrence of ventricular tachycardia (group 1 versus 2 and 3 p less than .001, Mantel-Cox and Breslow; group 2 versus 3 no difference). Thus, making ventricular tachycardia more difficult to induce is a sufficient criterion to predict long-term efficacy of an antiarrhythmic drug regimen.

Adult↗
PubMed1986

[Therapy of refractory ventricular tachycardia by transvenous electrical ablation].

In 6 patients (mean age 49 +/- 11 years) with chronic recurrent ventricular tachycardia which were relatively slow during antiarrhythmic therapy and had been proven to be resistant to various antiarrhythmic drugs, catheter ablation of the site of origin of ventricular tachycardia was performed after endocardial activation and/or pace-mapping. According to the results of catheter mapping, the sites of origin of ventricular tachycardia were in the region of the infero-lateral wall (n = 3), in the anterolateral wall (n = 1) and in the right ventricle (n = 2). In 3 cases, two ablative procedures were performed as the first was only transiently successful. A total of 51 shocks was delivered (200 J 45 times, 100 J 5 times and 400 J once). The following complications were observed: multiple episodes of spontaneous, partly polymorphous ventricular tachycardia which degenerated into ventricular flutter on several episodes (n = 1); transient third degree AV-block and intermittent complete right bundle branch block (n = 1); transient ST-elevation (n = 3); and self-terminating atrial tachycardia lasting for several minutes (n = 1). Immediately after the first ablative procedure, either no ventricular tachycardia could be induced any longer (n = 2) or non-clinical ventricular tachycardia was induced (n = 2). In the remaining 2 patients, programmed ventricular stimulation was not repeated immediately at the end of the ablative procedure. During a follow-up study at the end of the first week, the clinical ventricular tachycardia could be induced again in 3 of 4 cases. In 3 cases, a second ablative procedure was performed because of recurrences of ventricular tachycardia (n = 2) or syncope (n = 1). During final follow-up (mean 4.3 +/- 3.4 months), no recurrences of ventricular tachycardia were observed in 5 cases. In one case, recurrences occurred. Therefore, an automatic cardioverter was implanted. In conclusion, these preliminary results show that catheter ablation of drug-resistant ventricular tachycardia is feasible and may be an alternative to surgical procedures.

Adult↗
PubMed1986

[Heart involvement in progressive external ophthalmoplegia (Kearns-Sayre syndrome): electrophysiologic, hemodynamic and morphologic findings].

The Kearns-Sayre syndrome is combined with a progressive external ophthalmoplegia (PEO), retinal pigmentary degeneration and heart block. In some patients, progression of incomplete forms has been described and potentially fatal conduction disturbances may occur. The disease is considered as a systemic mitochondrial disorder. As part of an ongoing prospective study 6 patients (3 female, 3 male; age 32 +/- 9 years) with PEO and typical ultrastructural changes of a mitochondrial myopathy in their skeletal muscle were examined. The ECG disclosed atrio/intraventricular conduction defects in 5 patients: 1 patient had a third degree AV block which was treated by a pacemaker. Another patient had left anterior fascicular block with complete right bundle branch block. In 3 other patients an incomplete right bundle branch block was registered. In 1 patient, His-bundle electrography disclosed a block distal to His by atrial high rate pacing before and after i.v. injection of ajmaline; prophylactically a pacemaker was implanted. The mean HV-interval increased significantly under ajmaline by 44% in patients with sinus rhythm. Hemodynamic studies were normal in 5 patients at rest; only 1 patient was abnormal during exercise. Myocardial biopsy demonstrated mitochondrial abnormalities such as variability in shape and size. In 4 patients concentric cristae mitochondriales were seen. Our results suggest that atrioventricular conduction defects are common in patients with PEO. By means of endomyocardial catheterbiopsy a mitochondrial cardiomyopathy could be detected.

Adolescent↗
PubMed1986

Ventricular late potentials and inducible ventricular tachyarrhythmias as a marker for ventricular tachycardia after myocardial infarction.

To assess the predictive value of ventricular late potentials and programmed ventricular stimulation, 379 patients without a history of sustained ventricular tachycardia, dizziness or syncope were studied prospectively. Group I included patients referred for coronary angiography. Group II consisted of patients who survived an episode of acute myocardial infarction and who were studied within 6 weeks after onset. During follow-up (mean 13 months), 16 patients died. Six of these patients died suddenly within one hour. The prevalence of sudden cardiac death was lower (0.8%) in group I compared to group II (3.0%). There was no correlation between results of both methods and the subsequent occurrence of sudden cardiac death. Symptomatic sustained ventricular tachycardia was documented in 10 patients (2.6%). Only one patient in group I later developed symptomatic sustained ventricular tachycardia in contrast to nine cases in group II. Symptomatic sustained ventricular tachycardia could be predicted in patients in the early postmyocardial infarction period (group II). By using various combinations of parameters, the highest predictive value for subsequent sustained ventricular tachycardia was reached by the following combination: Late potentials of 40 ms duration or more, induction of monomorphic sustained ventricular tachycardia at rates below 270 beats min-1 and interval after myocardial infarction less than 6 weeks. In conclusion, both techniques seemed to be promising for the identification of patients at risk of ventricular tachycardia after myocardial infarction.

Action Potentials↗
PubMed1986

[Therapy of severe propafenone poisoning--an attempt at elimination by hemoperfusion].

After suicidal ingestion of 9 g Propafenone, a 31-year-old woman showed unconsciousness, cerebral convulsions, respiratory depression, sinus arrest, ventricular tachycardia and recurrent atrioventricular block. The maximum Propafenone plasma level was 4,702 ng/ml. Only 67.2 mg of Propafenone were eliminated within 4 h of hemoperfusion. Successful therapy could be achieved by symptomatic intensive care treatment. Additionally, 2 X 25 ml of 20%-saline solution were infused. In this case no efficacy of hemoperfusion in the treatment of Propafenone intoxication could be documented.

Adult↗