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Biomedical subjects

R R Abendroth

Publications and source records attributed to R R Abendroth.

At least 19 recordsLinked to original sources
PubMed1985

[Cimetidine and ranitidine in intensive care patients. Double-blind randomized cross-over study on intravenous administration: hemodynamics, plasma coagulation, blood gases and acid-base status].

Intravenous cimetidine 200 mg, and ranitidine 50 mg were administered as 2 minute infusions to 50 intensive-care patients. Cimetidine and ranitidine differed significantly in their effect on systolic arterial blood pressure measured during the second minute (alpha = 0.01). In the case of cimetidine the haemodynamic parameters measured over 10 minutes revealed a clearly defined fall in systolic, diastolic and mean arterial blood pressure as well as a rise in heart rate. The initial values were regained 5 minutes after drug application. Adverse effects of ranitidine on haemodynamics were much less than those of cimetidine. Neither drug produced any essential change in clotting parameters (partial thromboplastin time, plasma thrombin time, thromboplastin time and fibrinogen) measured before and 5 minutes after application, nor had they any effect on blood-gases or acid-base status.

Acid-Base Equilibrium↗
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

[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

[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↗
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

[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↗
PubMed1981

[Non-invasive recording of late ventricular potentials--methodology and first clinical experiences (author's transl)].

Late potentials occurring 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 hz at a sampling rate of 10 khz. The number of repetitions of the averaging process ranged between 150 and 300. 52 patients were studied. In 11 control subjects, no late potentials were detected within the ST segment. Late potentials were observed in 3/27 patients without previously documented ventricular tachycardia, all having left ventricular aneurysms. All three patients had evidence of increased ventricular vulnerability (one dying from ventricular tachycardia, one with stimulus-inducible ventricular tachycardia, one with multiple episodes of ventricular fibrillation after surgery). In patients with previously documented ventricular tachycardia and/or fibrillation, late potentials occurred in 7/14 cases (50%), mainly in those with aneurysms (6/8 pts = 75%). Mean onset of late potentials after the QRS complex was 38 +/- 20.1 ms, mean amplitude was 3.9 +/- 2.0 uV, and mean duration was 17.1 +/- 5.4 ms. We conclude that late potentials, which represent late depolarization of a mass of ventricular tissue after slow conduction, herald increased susceptibility to ventricular tachycardia mainly in patients with ventricular aneurysms.

Adult↗
PubMed1981

[Prognostic significance of ventricular echo beats induced during programmed ventricular stimulation (author's transl)].

To determine the incidence and prognostic significance of the repetitive ventricular response, the present retrospective study was done in 123 patients (75 male, 48 female, mean age +/- S.D. 49 +/- 14 years) with a variety of cardiac rhythm disorders. Programmed right ventricular stimulation was done at a basic pacing rate of 120 b.p.m. using one (S2) and two (S2,S3) premature stimuli. The data were analysed as to the presence ro absence of a repetitive ventricular response and the outcome of the patients ((1) sudden death less than or equal to 1 h or documented ventricular fibrilllation without myocardial infaction without myocardial infarction; (2) survivors or patients dying from non-cardiac or non-suddenly). A repetitive ventricular response was observed in 45/123 patients (36.6%) after one and in 51/120 patients (42.5%) after two premature stimuli. It occurred in 9/9 patients with ventricular fibrilation and in 20/23 patients (87%) with ventricular tachycardia. Mean follow-up period was 84 +/- 37.1 weeks (+/- S.D.). Five patients were lost to follow-up. 17/123 patients were classified as sudden death patients, the remaining patients were regarded as surviving (or dying non-suddenly). After one premature stimulus, a repetitive ventricular response was observed in 34.9% of survivors and in 47.1% of non-survivors (n.s.). After two premature stimuli, the incidence of a repetitive ventricular response increased from 36.8% in survivors to 70.6% in non-survivors (p less than 0.005). 12/106 of patients (11.3%) surviving and 10/17 patients (58.8%) non-surviving had more than three ventricular echo beats (p less than 0.005). All patients non-surviving who demonstrated a repetitive ventricular response has intraventricular reentry. Depending on the regidity of the criteria used (i.e. number of echo beats), the sensitivity of the test ranged between 47 to 88%, whereas the specificity ranged between 44 to 94%. The number of false-positives was high (43 to 80%); however, the number of false-negatives was low (4 to 8%). Concluding, this retrospective study has shown a correlation between sudden death and the incidence and number of repetitive ventricular response (depending on the number of premature stimuli) and the type of reentrant beats (bundle branch reentry or intraventricular reentry).

Adult↗
PubMed1981

[Electrophysiological effects of the new antiarrhythmic drug flecainide (R 818) in man (author's transl)].

The electrophysiological effects of the new antiarrhythmic drug Flecainide (R 818) was tested in altogether 27 patients with and without disturbances of sinus node function and intraventricular conduction. Flecainide was given intravenously in a dose of 1 mg/kg and 2 mg/kg. Constant "therapeutic" plasma levels were reached by application of 1 mg/kg as a bolus and an additional infusion of 1 mg/kg during the test period of 20 min. The drug had no significant effects on sinus node function even in patients with sinus node dysfunction tested so far. Intracardiac conduction time was prolonged within all compartments of the heart in a dose-dependent manner. After bolus injection of 1 mg/kg, the HRA-A interval lengthened by 10.4%, the A-H interval by 13.5%, the H-V time by 15.7% and the V-RVA interval by 29.1% of the control value. In addition, the QRS complex widened by 8.1%. After 2 mg/kg Flecainide the HRA-A interval was prolonged by 9.0%, the A-H interval by 24.4%, the H-V time by 40.2%, and the V-RVA interval by 16.5% of the control value. The QRS complex widened by 24.2%. In contrast, there was only a small and often insignificant increase in the refractoriness of the different compartments of the heart (5-15% increase of the control value). In two patients with bundle branch block, a higher degree A-V block distal the H potential occurred after 2 mg/kg Flecainide. These electrophysiological effects may explain some antiarrhythmic actions of Flecainide. In addition, possible side effects of the drug can be assessed. In patients with intraventricular conduction defects the drug should be used with caution especially when given iv in higher doses.

Adult↗
PubMed1981

[Clinical-electrophysiological study of the effect of lorcainide on induction of ventricular tachycardia (author's transl)].

11 patients (mean age 52 +/- 16.3 years) with recurrent ventricular tachycardia (VT), in whom VT could be initiated by programmed ventricular stimulation, were studied before and after lorcainide, a new antiarrhythmic agent. Lorcainide was either injected intravenously at a dose of 2 mg/kg within five to ten minutes (n = 3) or infused at a rate of 0.1 mg/kg/min up to the same total dose. After intravenous administration, there was no change in inducibility of VT in three patients, whereas in seven patients VT was either more difficult to induce requiring two instead of one premature beat (n = 2) or a higher rate of basic pacing (n = 2) or VT was no longer inducible (n = 3). In one case, VT was easier to induce. In patients with still inducible VT, the rate of VT decreased from 220 +/- 33 b.p.m. to 186 +/- 49.1 b.p.m. (non-significant). The echo zone for initiation of VT did not show any consistent change. The coupling interval between the last stimulated complex and the first beat of VT increased from 327 +/- 66.8 ms to 390 +/- 98.6 ms (p less than 0.05). The effective refractory period of the right ventricle increased slightly though not significantly. In three cases paradoxical side effects, probably due to lorcainide, were observed. The blood level of lorcainide at the end of injection or infusion immediately before right ventricular stimulation was 0.69 +/- 0.48 micrograms/ml (range 0.11 to 1.74 micrograms/ml). No N-dealkylated metabolite of lorcainide was detected after intravenous injection. Thus far, lorcainide is effective in preventing initiation of VT in some patients making it more difficult to induce in others. However, long-term efficacy and tolerance to the drug cannot be predicted from the data of this study though the data suggest that the drug might be effective on the long-term run against ventricular tachyarrhythmias.

Benzeneacetamides↗