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Biomedical subjects

G Breithardt

Publications and source records attributed to G Breithardt.

At least 451 records · Page 25Linked to original sources
PubMed1984

[Correlation of stimulus-induced ventricular echo beats and left ventricular function in patients without ventricular tachycardia].

110 patients (105 male, 5 female, mean age +/- S.D.: 52.9 +/- 5.9 years) with and without coronary artery disease were prospectively studied by programmed right ventricular stimulation (single and double premature stimuli during sinus rhythm and a paced ventricular drive of rates of 120, 140, 160 and 180 b.p.m.). The incidence of ventricular echobeats (VE) was correlated with angiographic and electrocardiographic findings. The end of the stimulation protocol was reached as soon as four or more ventricular echobeats were initiated. 0 to 3 VE occurred in 61/110 patients, 4-9 VE in 31 patients (28%), and greater than or equal to 10 VE were induced in 16 patients. Four or more VE were initiated in 68% of cases up to a paced ventricular rhythm of 120 b.p.m. after one or two premature stimuli. Patients with abnormal results of stimulation showed a tendency to an increase in the frequency of ventricular extrasystoles and couplets during long-term ECG recording. 86% of the patients with normal angiographic findings had 0-3 VE and 14% greater than or equal to 4 VE. In 49% of the patients with abnormal left ventricular function, 0-3 VE and in 51%, greater than or equal to 4 VE could be induced. The type of left ventricular contraction abnormality was significantly correlated to the results of programmed ventricular stimulation. greater than or equal to 4 VE were observed in 74% of patients with anterior wall myocardial infarction. Patients with inferior wall myocardial infarction had greater than or equal to 4 VE in 54% of cases. Ventricular tachycardia was induced in 30% of patients with anterior and in only 12% of patients with inferior wall myocardial infarction (n.s.). To conclude, this prospective study has shown a correlation between the incidence of inducible ventricular echobeats in response to programmed ventricular stimulation and left ventricular function. The prognostic significance of these findings has to be assessed.

Electric Stimulation↗
PubMed1983

[Diagnosis and therapy of ventricular tachycardias].

For the diagnosis of ventricular tachycardia the surface ECG is a sufficient diagnostic tool in most instances. Therefore, invasive electrophysiological studies are normally not indicated for diagnostic purposes, except if the tachycardia has not been documented up to now. However, invasive testing is necessary in every patient with VT for therapeutic reasons. During the study, the tachycardia is induced and terminated by programmed ventricular stimulation and the effect of different antiarrhythmic drugs tested. If no drug is able to suppress the induction of the tachycardia or to render it more difficult, alternative forms of therapy are to be considered. Implantable defibrillators and antitachycardial pacemakers are still at a developmental stage which does not allow a general application yet. In specialized centers, most of these intractable patients are undergoing electrophysiological operations. During operation the "focus" of the tachycardia is localized by means of epicardial and endocardial mapping and excluded by encircling subendocardial incision. In the last years, experimental and clinical studies are focusing on the so-called late potentials as markers for VT. These potentials can be recorded from the body surface by means of the signal averaging technique. Their clinical significance has not been fully established yet.

Cardiac Pacing, Artificial↗
PubMed1983

Arrhythmias in hypertrophic obstructive and non-obstructive cardiomyopathy.

The surgical therapy of hypertrophic cardiomyopathy (HOCM) has been shown to improve symptoms and the haemodynamic status. The prognosis after transaortic subvalvular myectomy seems to be relatively better compared to those patients with HOCM who undergo medical therapy. Complex ventricular arrhythmias have been shown to influence prognosis. Therefore, a study was undertaken to analyse the influence of surgery on ventricular arrhythmias in patients with HOCM. Thirty-one patients (23 male, eight female), mean age 44 +/- 13.6 years (range 13 to 72 years) underwent 48 h ambulatory monitoring pre- and postoperatively. Additionally 15 patients with hypertrophic non-obstructive cardiomyopathy (HNCM) were studied. Mean age was 49 +/- 11.5 years (range 28 to 69 years). Complex ventricular arrhythmias were defined as pairs (two consecutive QRS complexes) or non-sustained ventricular tachycardia (VT) (much greater than 3 QRS). Results in the operative group (HOCM) were as follows: The overall frequency of ventricular extrasystoles was low. There was no difference in the mean hourly ventricular extrasystole counts pre-operatively as compared to postoperatively. Thirteen patients had no pairs or VT pre- and postoperatively. Six patients had VT or pairs pre- and postoperatively. In five patients complex arrhythmias were detected only before surgery, whereas in another seven patients VT was first documented after operation. Overall, 11 patients had complex ventricular arrhythmias pre-operatively (pairs n = 3; VT n = 8, 3 to 8 QRS, rate 142 +/- 15 beats/min). Thirteen patients had complex ventricular arrhythmias after operation (pairs n = 4; VT n = 9, 4 to 10 QRS, rate 150 +/- 40 beats/min). Results in patients with HNCM were as follows: The overall frequency of ventricular extrasystoles was low, only three patients had a mean extrasystole count of more than 20 beats/h. Five patients had pairs and three patients ventricular tachycardia (5 QRS, rate 110 to 160 beats/min).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

[Detection of aprindine and its metabolites in plasma and urine].

In 36 patients with cardiac arrhythmias (predominantly ventricular premature beats), who were on oral aprindine long-term therapy with 50 to 400 mg daily, plasma levels were measured by gas chromatography after 3.5 hours of the last administration. There was a general dependency of plasma levels on the given dose, however, with considerable overlapping in individual values. In 24 patients the arrhythmias ceased, in six patients there was a clear, in two a moderate improvement. There was no clear therapeutic effect in four patients who were treated with a daily dose of 50 and 100 mg, respectively. Among the 36 patients, three who had plasma levels exceeding 2 micrograms/ml developed tremor and dizziness. After dose-reduction these side effects disappeared. The present results suggest that therapeutic plasma levels of aprindine are in the range of 1.0 to 1.75 micrograms/ml. A plasma level of 2 micrograms/ml should not be exceeded because of the possibility of side-effects. In six healthy males time-concentration curves of aprindine and its metabolites in plasma and urine were measured by gas chromatography. From the results a two-compartment model may be applied, the half-life of elimination was calculated to be 37 hours (plasma) and 31 hours (urine). With respect to the metabolites, in plasma only des-ethyl-aprindine (DEAP), in urine DEAP, hydroxy-, des-phenyl- and des-indanyl-aprindine could be found. Unlike aprindine, the DEAP-concentration curve in plasma showed a very slight decrease until the end of the 96-hour period of determination.

Aprindine↗
PubMed1982

[Mitral valve prolapse and platelet activity in young patients with cerebral ischaemia (author's transl)].

In 47 patients under 45 years of age (average age 35.4 years) with more or less localised cerebral ischaemia without evidence of arteriosclerosis echocardiography showed mitral valve prolapse in 13 cases. This was slightly more frequent than in an age and sex-matched control group. The difference was not statistically significant. In three quarters of the patients (n = 35) a significantly raised beta-thromboglobulin level was found indicating increased platelet activity. No definite conclusions can be drawn as to the cause of cerebral ischaemia which is probably due to embolism. However, treatment with platelet aggregation inhibitors should be considered.

Adult↗
PubMed1982

Effects of antiarrhythmic surgery on late ventricular potentials recorded by precordial signal averaging in patients with ventricular tachycardia.

In seven patients with documented ventricular tachycardia (VT) and prior myocardial infarction, late potentials (LP) were recorded at the end of or after the QRS complex from the body surface using high-gain amplification and the signal averaging technique (RC filter settings 100 to 300 Hz). In 6 to 7 patients VT could be initiated by programmed right ventricular stimulation; in one case, VT was inducible only from the left ventricle during surgery. Surgery was guided by epi- and endocardial mapping. In most cases besides resection of scar tissue, a partial or complete subendocardial encircling ventriculotomy was performed. Postoperatively, LPs were abolished in five cases, VT being no longer inducible. In the remaining two patients, LPs were still present. VT was still inducible in one of these two cases whereas in the other case, no programmed testing was done postoperatively. These data suggest that the abolition of LPs by surgery is closely related to the disappearance of the propensity to stimulus-induced VT. Thus, the averaging technique represents a new approach to the noninvasive control of the efficacy of surgery in patients with VT and prior myocardial infarction.

Adult↗
PubMed1982

Prevalence of late potentials in patients with and without ventricular tachycardia: correlation with angiographic findings.

Late potentials occurring at the end of or after the QRS complex were searched for from the body surface using high gain amplification and signal averaging techniques with filter settings between 100 and 300 hertz. The number of repetitions of the averaging process ranged between 150 and 300. Two hundred thirty-six patients were studied. In 27 control subjects, no late potentials were recorded. Among 146 patients without ventricular tachycardia or fibrillation, late potentials were present in 49 (34 percent). The mean duration of late potentials was 31 +/- 15.3 ms (median 25). Of 63 patients with documented ventricular tachycardia or fibrillation, 45 (71 percent) had late potentials (mean duration 51 +/- 31.5 ms; median 50) (probability [p] greater than 0.001). There was a close correlation between the detection of late potentials and left ventricular function. Late potentials occurred more frequently in patients with than in those without ventricular akinesia or aneurysm and in patients with than in those without ventricular tachycardia or fibrillation. In conclusion, late potentials are a frequent finding in patients with regional contraction abnormalities, both in patients with and in those without documented ventricular tachycardia. The greater prevalence and longer duration of these signals in patients with ventricular tachycardia or fibrillation might be responsible for the greater susceptibility to ventricular tachycardia. Long-term follow-up studies will be necessary to assess the possible prognostic significance of late potentials in patients without previously documented ventricular tachycardia or fibrillation.

Angiocardiography↗
PubMed1982

Electrophysiological actions of calcium antagonists in the heart.

Electrophysiological studies have shown that Ca antagonists affect only cardiac structures in which impulse propagation is mediated by the slow channel, i.e., mainly the sinoatrial and atrioventricular nodes. In addition they may depress abnormal slow conduction in diseased fibers. Ca antagonists do not represent a homogeneous group as different compounds seem to have different electrophysiological actions. In man, Ca antagonists normally have no significant effect on sinus node function. However, in patients with sinus node dysfunction, the same drugs may induce dangerous bradycardia or sinoatrial block. These different effects seem to be at least in part due to the different responsiveness of the normal and diseased sinus node to changes in autonomic tone via the baroreceptor reflex. In the A-V node, conduction and refractoriness are prolonged by each Ca antagonist to a different degree. In this regard, D 600 and verapamil have a very strong effect, whereas nifedipine in normal doses does not influence A-V nodal conductivity, and tiapamil and diltiazem have an intermediate position between these extremes. The results may have clinical relevance for antiarrhythmic therapy with Ca antagonists. In addition, they can help to avoid dangerous side effects in patients with disease of the sinus or A-V node.

Atrioventricular Node↗
PubMed1982

[Electrophysiological findings and follow-up in patients with syncope (author's transl)].

92 patients (mean age 54 +/- 14.7 years, 54 men) with unexplained syncopes were investigated by Holter monitoring, exercise testing and His-bundle-electrography (high-rate and programmed atrial stimulation). The diagnoses on 43 patients were sinus node dysfunction, in 32 cases atrio and/or intraventricular block, and in 6 patients idiopathic atrial fibrillation, whereas 8 patients had a history of ventricular tachycardia, 48 patients received a pacemaker (mean age 58 +/- 12.9 years), and 44 patients were discharged without a pacemaker (mean age 49 +2- 15.6 years). The mean duration of follow-up was 56 +2- 17.1 months. There were 13 deaths, 9 patients died from heart failure, 1 died suddenly, and 3 patients died from non-cardiac causes. 7 patients were lost to follow-up. 54 patients had no syncope any longer, while in 18 cases syncope was still present, 14 patients without pacemaker and 4 patients with pacemaker still had attacks. The cardiac mortality was 18.8% (with pacemaker) and 2.3% (without pacemaker). The only sudden cardiac death was observed in a patient with pacemaker. This study shows that pacemaker implantation bases on electrophysiologic study is able to improve symptoms in patients with syncope. However, the long-term prognosis of the patients is mainly depending on the severity of their underlying heart disease.

Adult↗
PubMed1982

[Effect of flecainide on chronic ventricular arrhythmias (author's transl)].

After an initial pilot study in five patients, the effect of flecainide on chronic ventricular arrhythmias was tested during 48-hour oral administration of 250 mg twice a day in nine further patients with previously drug-resistant chronic, stable ventricular arrhythmias. Mean age was 45.9 +/- 14.9 years; seven patients were male. Three patients had coronary artery disease, whereas the diagnoses in the remaining patients were congestive cardiomyopathy, aortic stenosis or no apparent heart disease. Continuous Holter monitoring with quantitative evaluation was performed in all patients for 24 hours before and during a two days' period of treatment. The mean number of ventricular ectopic beats decreased from 20.3 +/- 6.4 beats/min during hour six of treatment and further to 3.1 +/- 7.7 beats/min during hour 25 to 48 after onset of treatment. In either of nine patients, the mean decrease in ventricular ectopic rate was 97.5%. In only one patient, therapy was ineffective, Ventricular couplets were completely suppressed in six of eight cases. Looking at the spontaneous variability of ventricular ectopic beats during the control period, eight of nine patients showed a decrease which considerably exceeded the statistically necessary one. Headache of moderate degree was reported in one case in the pilot study. Therapy had to be stopped after the first dose because of QRS widening in another patient. In conclusion, this short-term study suggests that flecainide may be an effective drug for the management of ventricular arrhythmias.

Adult↗
PubMed1982

[Response of ventricular late potentials after surgical therapy of ventricular tachycardia].

19 patients with either previously documented sustained ventricular tachycardia (VT) (n = 16) or only inducible VT (n = 3, one of whom had recurrent syncope), due to previous myocardial infarction were studied pre- and postoperatively. Mean age was 53 +/- 6 years, 16 were male, 3 female. In all but one, VT could be induced preoperatively by programmed right ventricular stimulation. Late potentials (LP) were recorded at the end of or after the QRS-complex from the body surface using high-gain amplification and the signal averaging technique (RC-filter settings 100 to 300 Hz). Indication for surgery was either intractable VT or bypass grafting and/or aneurysmectomy. Preoperatively, mean duration of late potentials was 54 +/- 37.7 ms, mean amplitude was 12 +/- 14.0 mean V. Surgery was guided by epi- and endocardial mapping. In 14 cases endomyocardial encircling ventriculotomy was the main procedure, whereas in 5 patients only aneurysmectomy and bypass grafting were performed. Postoperatively, late potentials were no longer detectable in 12 cases, whereas in 6 of 7 cases there was a decrease in duration, but no essential change in amplitude. A postoperative electrophysiological study was performed in 18 cases. In those 12 patients with abolition of LPs, the maximal number of inducible ventricular echo beats using an extended stimulation program from three right ventricular sites, ranged between 1 and 5 in 9 cases, between 10 and 11 VE in 2 cases, whereas VT was induced in only 1 case. In 6 patients in whom LPs were still detectable, ventricular tachycardia could still be induced in 2 cases and a maximal response of ten echo beats was observed in another patient. Abolition of LP by surgery is closely related to the disappearance of the propensity to stimulus-induced VT. Thus the averaging technique may provide a non-invasive procedure to assess the successful outcome after operation for ventricular tachycardia. If, however, LPs are still present, this does not exclude successful surgical abolition of the propensity to ventricular tachycardia.

Cardiac Pacing, Artificial↗
PubMed1982

[Electrophysiological effects of flecainide on stimulus-inducible ventricular tachycardia].

13 patients (54 +/- 11.8 years) with either spontaneously occurring ventricular tachycardia (N = 12) or recurrent syncope (n = 1) probably due to ventricular tachycardia were studied electrophysiologically. In all patients, ventricular tachycardia could be initiated by programmed right ventricular stimulation during the control study. Ventricular tachycardia was sustained in eleven patients and non-sustained in the remaining two. After several days of oral administration of flecainide (400 to 500 mg per day) sustained ventricular tachycardia could still be initiated in seven cases that had to be interrupted by overdrive stimulation in five cases, and by cardioversion in the remaining two. In six cases, short, self-terminating episodes of ventricular tachycardia were induced. In four patients, induction of ventricular tachycardia was unchanged or made easier, whereas in seven cases ventricular tachycardia was more difficult to induce (i.e. later during the step-like stimulation program). The mean rate of induced ventricular tachycardia decreased from 215 +/- 59.4/min (+/- S.D.) to 169 +/- 44.1/min during flecainide (p less than 0.025). The interval between the tachycardia-initiating beat and the first beat of tachycardia increased from 323 +/- 61.1 ms to 438 +/-148.3 ms (P less than 0.02). The effective refractory period of the right ventricle was prolonged from 240 +/- 20.5 ms t 279 +/- 37.3 ms (P less than 0.005). The plasma concentration of flecainide at the time of stimulation was 995 +/- 238 ng/ml. Thus, flecainide exerts a marked effect on the rate of induced ventricular tachycardia, whereas the mode of induction did not change considerably. The prophylactic effect of long-term therapy with flecainide in patients with recurrent ventricular tachycardia needs further studies.

Adult↗
PubMed1982

The surgical treatment of ventricular tachycardias. Simple aneurysmectomy versus electrophysiologically guided procedures.

Between 1971 and 1982, 41 patients were operated upon for recurrent sustained ventricular tachycardia. All but three had severe coronary artery disease with a history of myocardial infarction. In 10 patients (Group I) simple aneurysmectomy with or without aorta-coronary bypass grafting was done. Thirty-one patients (Group II) had an electrophysiologically guided procedure, mainly partial or complete encircling endocardial ventriculotomy (EEV) at the earliest source of electrical activity during ventricular tachycardia. The results in the two groups indicate a clear superiority of electrophysiologically guided procedures over a simple aneurysmectomy regarding early and late disappearance of tachycardiac rhythm problems (p = 0.01); the differences between the two groups in hospital mortality (p = 0.43) and long-term survival are not significant. We compared our data with results in 160 cases of simple aneurysmectomy and 224 cases of electrophysiologically guided operations recently published in the literature. This comparison confirms the higher efficiency of mapping-guided procedures in eradicating ventricular tachycardias. The improvements in hospital and long-term survival, again, are not significant.

Adult↗