Search PubMed⌕ Search

Biomedical subjects

G Breithardt

Publications and source records attributed to G Breithardt.

At least 433 records · Page 24Linked to original sources
PubMed1985

Automatic identification of late potentials.

The purpose of the present study was to develop an algorithm for the automated identification of ventricular late potentials (LP) that can be recorded non-invasively by means of the signal averaging technique. This new algorithm was designed to determine the possible presence and the onset and duration of a given LP by analyzing the end of the QRS complex. As there is no objective standard for identifying these late potentials, the new algorithm was developed by continuous comparison and adaptation to visual analysis in 65 patients (algorithm definition phase). In the subsequent trial phase, visual and automated analysis were compared in a second cohort of 50 patients (40 patients with and 10 patients without late potentials). In the latter 50 patients, the results obtained with the new algorithm corresponded to the analysis made by at least two of three independent observers in 92% of cases. In only four patients--one without and three with late potentials--there was no agreement between the observers and the new program. In conclusion, the new algorithm can be used reliably for the evaluation of late potentials. The results are more objective. They are reproducible, which is of great advantage when data from different groups are to be compared or when less experienced investigators are using non-invasive methods for registration of late potentials.

Arrhythmias, Cardiac↗
PubMed1985

[Therapy-refractory permanent ventricular tachycardia in the immediate postinfarct period--treatment using endomyocardial ventriculotomy].

Endocardial encircling ventriculotomy was carried out in a 47-year-old male patient because of recurrent drug-resistant permanent ventricular tachycardia complicating acute myocardial infarction. Earliest activation during ventricular tachycardia determined by intraoperative mapping was recorded from the left side of the interventricular septum. At this site, a parital encircling endocardial ventriculotomy was performed. Postoperatively, there was no spontaneous recurrence of ventricular tachycardia. During a postoperative electrophysiologic study, no ventricular tachycardia could be induced. These results indicate that map-guided surgery may be carried out successfully in selected patients with drug-resistant ventricular tachycardia complicating the acute phase of myocardial infarction.

Cardiac Pacing, Artificial↗
PubMed1985

[Prognostic significance of programmed ventricular stimulation in the noninvasive registration of ventricular late potentials in the postinfarct period].

The prognostic significance of programmed ventricular stimulation for assessing ventricular vulnerability and of signal averaging for detection of ventricular late potentials was assessed prospectively in 132 survivors of acute myocardial infarction. The median day of these studies was the 22nd. Programmed ventricular stimulation (PVS) included single and double premature stimuli during sinus rhythm and paced ventricular rhythms at rates of 120, 140, 160 and 180 bpm. The endpoint for stimulation was the induction of 4 or more consecutive echo beats. 59 of 132 patients (45%) had late potentials in their body surface signal-averaged ECG. The prevalence was 35% in those with anterior wall infarction and 54% in those with inferior wall infarction (chi 2 = 3.9; p less than 0.05). In 61 patients (46%), 4 or more consecutive echo beats were induced. In 28 of these patients, sustained ventricular tachycardia or fibrillation were initiated. During follow-up (15 +/- 11 months; mean +/- S.D.), there were 4 sudden deaths. Neither PVS nor signal averaging were able to predict these events. Spontaneous symptomatic sustained ventricular tachycardia occurred in a total of 9 patients, all of whom had an abnormal PVS result (sensitivity 100%); 7 of these patients also had late potentials (sensitivity 78%). Stepwise analysis revealed that the combination of late potentials (duration greater than or equal to 40 ms), and of induction of sustained ventricular tachycardia at rates less than 270 bpm had the highest predictive value (50%). In contrast, the prevalence of sustained ventricular tachycardia was as low as 3% in those without late potentials.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Pacing, Artificial↗
PubMed1985

[Transvenous electric ablation of an accessory pathway in supraventricular re-entry tachycardias refractory to therapy].

Transvenous catheter ablation of a concealed accessory pathway was attempted twice in an 18-year-old patient with dilatative cardiomyopathy and drug-refractory supraventricular tachycardias. The postero-septal concealed pathway was successfully ablated by the catheter technique without interruption of the normal, anterograde AV-nodal conduction. Accessory pathway conduction did not recur during 4 months of follow-up.

Adolescent↗
PubMed1985

[Electrophysiologic effect of sotalol in supraventricular tachycardias].

The electrophysiological effects of sotalol, a beta-blocking drug with class III antiarrhythmic properties were assessed in 20 patients (mean age 33 +/- 14.3 years) with supraventricular tachycardias. Sixteen patients had Wolff-Parkinson-White syndrome (overt n = 9, concealed n = 7), three patients AV-nodal reentrant tachycardias and another patient atrial tachycardias. Sotalol was administered intravenously (n = 16) in a dose of 1.5 mg/kg over 15 min. The effects of 320 to 480 mg/day oral sotalol were assessed in 7 patients. By intravenous and oral application of sotalol a significant increase in the AH interval, the refractory periods of the atrium and ventricle as well as a decrease of the antegrade and retrograde conduction capacity of the AV node or the accessory pathway were observed. The mean R-R interval during induced atrial fibrillation increased significantly in patients with Wolff-Parkinson-White syndrome from 224 +/- 52 ms to 277 +/- 59 ms (p less than 0.05). In 10 patients, sotalol was administered during supraventricular reentrant tachycardia. The cycle length of supraventricular tachycardia increased from 276 +/- 90 ms to 358 +/- 25 ms (p less than 0.01). The tachycardia terminated in 7 patients: in 5 patients block was observed in the AV node, while in another 2 patients tachycardia terminated retrogradely. After intravenous application supraventricular arrhythmias were no longer inducible in 5 of 12 patients. In a further 4 patients only non-sustained supraventricular tachycardias (4-20 QRS complexes) were inducible. In 2 patients the supraventricular tachycardia terminated distal to the His bundle.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

Effect of propafenone in the Wolff-Parkinson-White syndrome: electrophysiologic findings and long-term follow-up.

The electrophysiologic and long-term efficacy of propafenone, a relatively new antiarrhythmic agent, was assessed in 47 patients with accessory pathways. In 23 patients (group I), the electrophysiologic effects were assessed initially. In 19 patients in this group and in 24 additional patients (group II), long-term therapy with oral propafenone was initiated. The mean age of the patients was 38 years in group I and 41 years in group II. The duration of a history of tachycardia in both groups was 12 years (mean); 14 patients previously had had attacks of syncope. During the electrophysiologic study in group I, propafenone did not change the spontaneous sinus rate. Corrected sinus node recovery time as well as the AH interval, HV time, QRS duration and effective refractory periods of the atria and ventricles was significantly prolonged. The effective refractory period of the accessory pathway increased from 238 to 322 ms (p less than 0.02). The 1:1 conduction capacity of the accessory pathway decreased from 231 to 176 beats/min (mean; p less than 0.01). Complete block in the anterograde direction occurred in 6 patients. The shortest RR interval during atrial fibrillation increased from 232 to 303 ms (p less than 0.05). The retrograde refractory period of the accessory pathway was prolonged from 245 to 295 ms (p less than 0.01). Complete or 2:1 retrograde block during basic drive occurred in 3 patients and 1 patient, respectively. In 6 of 15 patients, propafenone made sustained supraventricular tachycardia (SVT) either no longer inducible or nonsustained. The cycle length of induced SVT increased from 324 to 395 ms (p less than 0.01). During long-term administration (follow-up duration 2 to 3 years), 17 of 43 patients did not report any episode of symptomatic tachycardia. In another 18 patients, tachycardia was rare, slower and self-terminating. In only 3 patients, the frequency and severity of attacks had not changed. One patient with dilated cardiomyopathy died suddenly. Side effects necessitating discontinuation of medication were observed in only 2 patients. The remaining side effects, if present, were tolerated, and dosage dependent. In conclusion, propafenone is an effective and well-tolerated antiarrhythmic agent in the long-term management of patients with the Wolff-Parkinson-White syndrome.

Adolescent↗
PubMed1984

Prevalence and clinical significance of the repetitive ventricular response during sinus rhythm in coronary disease patients.

The prevalence of the repetitive ventricular response (RVR) after single and double premature stimulation during sinus rhythm or a paced supraventricular rhythm at a rate of 85 bpm was assessed in 343 patients (group 1: 237 patients studied prospectively who were referred for coronary arteriography and ventriculography; group 2: 44 patients after recent acute myocardial infarction; group 3: 61 patients with documented ventricular tachycardia and/or fibrillation). In group 1 patients, RVR testing was performed from both the right ventricular apex (n = 237) and outflow tract (n = 190), whereas in the remaining patients only the apex was stimulated. In group 1, RVR after a single premature stimulus occurred in 21.9% and after two stimuli in 63.2%. In patients with normal left ventricular (LV) function (n = 63) the prevalence of RVR after a single stimulus was significantly less (9.5%) than in those with LV dysfunction (n = 174;26.4%,p less than 0.01). However, after double stimulation, there was no longer any difference. In group 2, the prevalence of RVR was 25% after one and 34.1% after two premature stimuli. In group 3 patients, RVR was observed in only 14.8% after one and in 41% of patients after two premature stimuli. Ventricular tachycardia (greater than or equal to 10 QRS) was induced in nine patients during a supraventricular rhythm. Two hundred thirty-seven patients of group 1, who were prospectively studied in order to assess the prognostic significance of the RVR, were followed for a mean period of 27.2 +/- 10.7 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

[Clinical and electrophysiologic findings in patients with syncope following myocardial infarct].

34 patients with syncope (median number of episodes 2) which remained unexplained after thorough medical and neurological evaluation underwent an intracardiac electrophysiological study with atrial and ventricular programmed stimulation. All patients had a history of well-documented myocardial infarction 24 months (median, 3-120) prior to the electrophysiological study. During programmed ventricular stimulation 6 patients had inducible ventricular fibrillation or flutter, and 10 patients had sustained ventricular tachycardia. In 14 patients non-sustained ventricular tachycardia was induced, whereas in only 4 patients 1 to 3 repetitive ventricular responses were induced. Therapy was instituted on the basis of electrophysiologic testing. During the follow-up of 8 months (median, 1-37) 27 patients had no recurrence of syncope. Syncope persisted and remained unexplained by the electrophysiological study in 3 patients. One patient had ventricular fibrillation and two died suddenly, two of these patients after having discontinued antiarrhythmic medication 2 weeks before. Another patient died of non-cardiac cause. It is concluded that 1) the results indicate a high ventricular vulnerability (88%) in patients with unexplained syncope after myocardial infarction, 2) the evaluation by electrophysiological studies may identify the potential mechanism for syncopes, 3) electrophysiological testing offers a rationale for specific prophylactic therapy.

Cardiac Complexes, Premature↗
PubMed1984

[The development of clinical electrophysiology. Indication, complications and results of 1296 invasive electrophysiologic studies from 1971 to 1981 in Düsseldorf].

The indications, complications and results of 1,296 clinical electrophysiological studies performed in D usseldorf between 1971 and 1981 are reviewed. In the first years, bradycardias (Sick sinus, AV conduction defects) were the main indications, whereas later on tachycardias played the dominant role. This holds especially true for ventricular tachycardias. In these patients, programmed pacing was used to control the efficacy of anti-arrhythmic treatment. The complication rate was low (1%).

Arrhythmias, Cardiac↗
PubMed1984

Surgical treatment of ventricular tachycardias. Complete versus partial encircling endocardial ventriculotomy.

Forty consecutive patients underwent electrophysiologically guided encircling endocardial ventriculotomy as treatment for recurrent sustained ventricular tachycardia resulting from coronary artery disease and previous myocardial infarction. Twelve patients (30%, Group I) had a complete encircling endocardial ventriculotomy and 28 (70%, Group II) had a partial encircling endocardial ventriculotomy (54.4% +/- 2.2% of the left ventricular endocardial circumference) at the earliest electrical activation during ventricular tachycardia. There were no significant differences between the two groups in age, sex ratio, New York Heart Association class, coronary disease, aneurysm location, concomitant bypass grafting, and left ventricular function. One patient of Group I and two patients of Group II did not survive the perioperative period (8% versus 7%, not significant). The survivors were restudied electrophysiologically about 3 weeks after the operation. Eight patients of Group I and 19 patients of Group II were free of ventricular tachycardia (no spontaneous or inducible ventricular tachycardia) without antiarrhythmic drugs (73% versus 73%, not significant). The mean follow-up period in Group I is 22.6 months and in Group II, 15.2 months. Five patients of Group I and of Group II developed severe left ventricular dysfunction (46% versus 8%; p = 0.025). Also, congestive heart failure was a significant cause of death in Group I patients (p = 0.036). In conclusion, electrophysiologically guided partial encircling endocardial ventriculotomy is highly efficient as a surgical treatment of recurrent sustained ventricular tachycardia. Complete encircling endocardial ventriculotomy offers no better ablation of arrhythmias and should be avoided because of its apparent hazards to left ventricular performance.

Coronary Disease↗
PubMed1984

[Incidence and prognostic significance of inducible ventricular arrhythmias in the early post-infarction phase].

To identify patients at risk of sudden cardiac death or sustained ventricular tachycardia (VT) after recent acute myocardial infarction, 100 patients younger than 70 years (80 male, 20 female; 47 anterior wall infarction, 53 inferior wall infarction) were studied prospectively. 25 days (mean) after onset of myocardial infarction, programmed ventricular stimulation was performed, including the introduction of single (S2) and double (S2-S3) ventricular extrastimuli both during sinus rhythm and at paced ventricular cycle lengths (S1-S1) of 500, 430, 370, and 330 ms. The end of the protocol was reached as soon as 4 or more consecutive ventricular echo beats (VE) were initiated. Four or more VE were initiated in 46% of patients, 4 to 9 VE in 21%, greater than or equal to 10 VE or sustained VT in 25%. During follow-up (15 +/- 8 months), 5 patients died suddenly (less than or equal to 1 h), and 5 further patients developed spontaneous sustained ventricular tachycardia. In 3 patients who died suddenly and 4 with spontaneous sustained VT, greater than or equal to 4 VE had been induced by programmed ventricular stimulation (sensitivity 60% and 80% respectively). With regard to sudden cardiac death and spontaneous ventricular tachycardia, the predictive value of a positive test was 15%, that of a negative (normal) test 94%. False negative results occurred in 6%, whereas 85% of all abnormal results had to be regarded as false positive, as these patients did not develop an arrhythmic event during follow-up. Thus patients after recent myocardial infarction frequently have signs of increased ventricular vulnerability during programmed ventricular stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias, Cardiac↗
PubMed1984

[Clinical and electrophysiologic findings following operative therapy of ventricular tachycardias].

40 patients with sustained ventricular tachycardia underwent either complete (n = 12) or partial (n = 28) endomyocardial encircling ventriculotomy ( EEV ). All patients had coronary artery disease, mean age 54 years. Aneurysmectomy was performed in 35 patients. 30 patients also received coronary artery bypass grafts. There were 3 perioperative deaths (7.5%): 1/12 with complete and 2/28 with partial EEV . All survivors underwent programmed right ventricular stimulation postoperatively. Ventricular tachycardia was not inducible in 23 of 36 patients (64%). One patient was not studied postoperatively. In contrast, sustained ventricular tachycardia was still inducible in 13 patients. Ventricular tachycardia was considered as "clinical" tachycardia in 9 patients whereas it was a "non-clinical" form in another 4 patients. Thus the electrophysiological failure rate with regard to "clinical" forms was 25%. In 2 of 4 patients with spontaneous recurrences during the first postoperative week, sustained ventricular tachycardia could not be induced during the postoperative electrophysiological study. During follow-up (mean 18 months), spontaneous recurrence of ventricular tachycardia occurred in 2 patients. Cardiac arrest possibly due to coronary bypass occlusion occurred in 1 patient who could be resuscitated. 6 patients died late postoperatively: 4 of congestive heart failure, 1 of re-infarction and 1 of fulminant pneumonia. 3/11 patients (27.3%) with complete and 1/26 (3.8%) with partial EEV died because of congestive heart failure (p less than .03). Thus abolition of spontaneous sustained ventricular tachycardia was successfully achieved in 94.6% of cases surviving surgery (91.9% if the patient with cardiac arrest is included.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrocardiography↗