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V Hombach

Publications and source records attributed to V Hombach.

At least 217 records · Page 12Linked to original sources
PubMed1986

Recovery of ventricular late potentials from body surface using the signal averaging and high resolution ECG techniques.

In 70 patients (3 females and 67 males), aged 16-72 years (mean: 51 +/- 9 years), the low noise ECG was recorded from body surface by the signal averaging and the high resolution beat-to-beat techniques. We found 61 patients were suffering from coronary heart disease, 4 had atypical coronary heart disease (syndrome X), 4 had dilatative cardiomyopathy, and one had the long QT syndrome (Romano-Ward syndrome). We found the following recovery rates for ventricular late potentials within the ST segment with the averaging technique: clearcut in 13/53 patients, doubtful in 16/53 patients, and late potentials absent in 26/53 patients. With the beat-to-beat technique the following recovery rates were found: clearcut late potentials in 27/70 patients, doubtful in 23/70 patients, none in 20/70 patients, and intermittently occurring late potentials in 18/70 patients (categorized as doubtful late potentials). When comparing the detection of late potentials with both methods in individual patients, we found concordant results in 39/53 patients studied (positive with both methods in 24/53 patients, negative with both methods in 15/53 patients), and discordant results in 14/53 patients (positive with the beat-to-beat technique and negative with the averaging technique in 12 individuals, negative with the beat-to-beat technique and positive with the averaging technique in the remaining 2 patients). The correlation between the incidence of late potentials and the presence of exercise-induced myocardial ischemia (submaximal bicycle exercise) was higher when using the high resolution beat-to-beat technique, as holds also true for the correlation to complex ventricular arrhythmias.(ABSTRACT TRUNCATED AT 250 WORDS)

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

Noninvasive control of the early postimplantation period.

Modern programmable pacemakers often incorporate features that allow one to perform a series of diagnostic maneuvers to aid in postimplantation surveillance. These features often include noninvasive measurements of thresholds, lead impedance, and intracardiac electrogram recognition via telemetry circuits. Interindividual differences in these measurements are so great that one must utilize individual comparisons for longitudinal studies of reliability. While these devices allow "fine tuning" of individual units, they require major time-consuming efforts and add to the total device costs.

Adult↗
PubMed1986

Beneficial effects of intracoronary nifedipine during percutaneous transluminal coronary angioplasty.

In twelve patients with coronary heart disease and hemodynamically significant coronary artery stenoses (LAD: 11, LAD plus RCA: 1) the effect of intracoronary nifedipine, 0.2 mg, on PTCA-related myocardial ischemia was evaluated. The severity of angina pectoris during balloon inflation was not significantly reduced by nifedipine, whereas the sum of ST segment alterations in Einthoven and Goldberger leads on inflation was significantly decreased by the drug. Before inflation intracoronary nifedipine lowered the systolic arterial blood pressure significantly, whereas diastolic and mean aortic pressure and heart rate remained unchanged. At the end of the inflation period heart rates were significantly faster after nifedipine, and the heart rate-blood pressure product higher with nifedipine. No significant correlations could be calculated between the extent of ST segment alterations and any of the hemodynamic parameters. From our results we conclude that, besides the possibility of ventricular afterload reduction, the beneficial cardioprotective effect of intracoronary nifedipine may mainly be attained by the local "cardioplegic" action of this substance.

Adult↗
PubMed1986

[Diastolic micropotentials in high-resolution surface ECG in QT syndrome].

Patients suffering from long QT syndrome are threatened by torsade de pointes tachycardias and sudden arrhythmic cardiac death. An inhomogenic sympathetic innervation of the heart with dominance of the left cervicothoracic sympathetic nerves has been considered to be a major cause of life threatening cardiac arrhythmias. This study presents the electrocardiographic and electrophysiologic results of 7 patients with long QT syndrome. In agreement with data published earlier our results of Holter monitoring, exercise testing and programmed electrical right ventricular stimulation were of no diagnostic or prognostic significance in predicting syncopal attacks or sudden arrhythmic cardiac death. Thus, the high resolution ECG methods played an important role in this study. During noninvasive recordings of signal averaged ECGs and high resolution surface ECGs with beat to beat registration, diastolic microvolt potentials could be detected in 6/7 patients within the ST segment and in 5/7 patients after the T wave. Our results evidently show that the signal averaged ECG and the high resolution surface ECG could be of diagnostic significance in patients with long QT syndrome.

Adolescent↗
PubMed1985

Haemodynamic and antiarrhythmic protective effects of intracoronary perfusion during percutaneous transluminal coronary angioplasty.

In 17 anaesthetized open-chest pigs, experiments were performed to determine if a myocardial protective effect can be obtained by intracoronary perfusion through the dilatation catheter during balloon inflation for percutaneous transluminal coronary angioplasty. Placement of the catheter such that the balloon lay in the middle third of the left anterior descending coronary artery caused a significant deterioration in haemodynamic status prior to balloon inflation, and on 5 occasions led to the development of ventricular fibrillation (VF). Balloon inflation without perfusion for periods of up to 5 min produced further haemodynamic deterioration, and culminated in VF in 4/14 cases. Simultaneous perfusion during balloon inflation (proximal perfusion pressure 900-1200 mmHg), with flow rates of 14.5 ml min-1 for arterial whole blood and 21 +/- 7 ml min-1 for blood diluted with 0.90% NaCl (haematocrit approx. 25%), not only prevented the haemodynamic deterioration but resulted in an improvement compared with values obtained with the catheter in position prior to balloon inflation. In no case did VF occur during 5 min of balloon inflation plus perfusion. The use of diluted blood as the perfusate was not associated with intracatheter thrombus formation, which was sometimes seen as a complication of whole blood perfusion.

Angioplasty, Balloon↗
PubMed1984

[Endocardial cardioversion--a new method for treating recurrent ventricular tachycardia].

The effect of endocardial cardioversion was investigated in 17 patients (aged 26-76 years), ten of them with ventricular tachycardia, either spontaneous or initiated by programmable stimulation. During a total of 14 days of observation there were 33 episodes of spontaneous or induced ventricular tachycardia. A special cardioverter catheter had been placed into the right ventricle and endocardial microshocks were given ranging from 0.05-2.0 J. All patients could feel the shock, but in most instances it was mild to moderate, in only one painful. The tachycardia was slowed in 20% of all microshocks, moderate acceleration occurred in 6%, while in 71% the tachycardia rate remained unchanged. In 7 out of 65 microshocks sinus rhythm occurred spontaneously, after an interval in which the tachycardia slowed. Atrial fibrillation was induced in 6% of cases, but there was no instance of ventricular fibrillation. Reversion directly to sinus rhythm after endocardial cardioversion occurred in 26 of 33 episodes of ventricular tachycardia, while in 7 episodes the tachycardia rate slowed. In no case was it necessary to use external DC cardioversion to terminate a ventricular tachycardia. Threshold values for successful cardioversion of ventricular tachycardia averaged 0.77 (+/- 0.63) J. In one patient, atrial flutter with a relatively high A-V conduction rate was converted into atrial fibrillation by an intra-atrial microshock of 5.0 J. Thus endocardial cardioversion proved effective and safe in terminating ventricular tachycardia, even in patients in whom anti-tachycardic ventricular pacemaker stimulation had failed. The method is apparently not suitable for the conversion of supraventricular tachy-arrhythmias to sinus rhythm.

Adult↗
PubMed1984

Noninvasive beat-by-beat registration of ventricular late potentials using high resolution electrocardiography.

We have developed a new high resolution ECG equipment for recording cardiac microvolt potentials from the body surface. Noise reduction has been achieved by specially designed suction electrodes, by spatial averaging of the electrocardiograms from four electrode pairs, using extremely low noise amplifiers, by performing registrations within a Faraday cage, and by teaching the patient to relax during end expiratory breath holding. Fourteen young males (controls) and 30 patients with various cardiac diseases (27 with CHD) were studied. In normals ventricular late potentials were not seen, but in 12/30 patients clearcut diastolic potentials were found. In 7/12 patients with positive findings, late potentials appeared beat-by-beat, in 5/12 patients those signals occurred intermittently, in 11/30 patients questionably, and in the remaining 5/30 patients no late potentials were recorded. One patient with the Romano-Ward syndrome revealed phases with stable beat-by-beat and intermittently occurring ventricular late potentials. These results demonstrate the feasibility of continuous non-invasive recording of ventricular late potentials, whose clinical and prognostic significance remains to be established.

Adolescent↗
PubMed1984

[Detection of patients at risk for sudden heart death by long-term ECG. The role of life-threatening ventricular arrhythmias].

Recognition of patients at risk of sudden cardiac death and prevention of such lethal events represent important and, for the most part, unresolved problems in clinical cardiology. From pathologic-anatomical and clinical studies of instances of sudden death it is known that in more than 80% the lethal electrical events, that is ventricular fibrillation, are attributable to myocardial ischemia, usually due to coronary artery disease. Experience in experimental studies as well as in treatment of patients with myocardial infarction on coronary care units has shown that certain types of arrhythmias such as frequent, multiform, repetitive and early-occurring (R-on-T) ventricular premature beats, in particular, may be associated with sudden arrhythmic cardiac death. Accordingly, in 1971, Lown and Wolf proposed a system for grading of ventricular arrhythmias and their severity which assumed world-wide importance for clinical and prognostic studies. This system of classification contains quantitative and qualitative criteria and is ordered in part on exclusion and in part on hierarchy, in which it is implied that the hierarchy of ventricular premature beats corresponds with that of the risk of death. Since the system enables only semiquantitative delineation of ventricular arrhythmias whose absolute number, however, within a given observation period appears to be of prognostic relevance and, additionally, since the Lown system is encumbered by the fact that classification is based only on the most severe arrhythmia with subsequent loss of information regarding concurrent arrhythmias of lesser severity, Bigger and his associates, in 1978, suggested a modification to provide quantification of all ventricular premature beats. In addition to the problems inherent to grading ventricular premature beats, further problems are also incurred with respect to spontaneous variability of ventricular arrhythmias. Based on statistical considerations and clinical studies accordingly, adequate assessment of complex ventricular arrhythmias prerequisites continuous monitoring for a period of 24 to 48 hours. Furthermore, for the exact recognition and quantitative detection of ventricular arrhythmias, the reliability of the individual systems for continuous ECG monitoring plays an important role since, by no means, have they all been validated in arrhythmia-detection capabilities. Since 1971, a number of clinical studies have shown, in particular, that complex ventricular arrhythmias are of important prognostic relevance in characterization of patients at risk of sudden cardiac death. The results may be summarized as follows: Ventricular premature beats can be found frequently in

Adult↗
PubMed1983

Dose dependence of tolerance during treatment with mononitrates.

In order to test the clinically supposed development of tolerance during chronic high-dose nitrate therapy, we studied a total of 24 patients with angiographically proven coronary heart disease at rest and during ergometric exercise (supine position, 50 w for 3 min). Pulmonary arterial pressure (PAP, floating catheter), arterial blood pressure (cuff method), cardiac output (Fick principle), heart rate, and exercise capacity (w X min) were measured at rest and exercise before and during chronic (4 weeks) oral therapy with 5-isosorbide mononitrate (5-ISMN), 3 X 20 mg/day (n = 14) and 3 X 50 mg/day (n = 10). After acute administration, both doses of 5-ISMN decreased mean PAP at rest and during exercise (rest: by 25% with 20 mg and by 29% with 50 mg; exercise: by 30% with 20 mg and by 45% with 50 mg), whereas cardiac output and stroke volume were only reduced by 5-ISMN at rest. During chronic treatment with 60 mg and 150 mg 5-ISMN, and additional administration of 20 mg or 50 mg respectively lowered PAP at rest by 15% and 19%; during ergometric exercise PAP was 22% and 14% lower than during ergometry before any drug treatment. The exercise capacity slightly increased during treatment to 60 mg 5-ISMN, whereas it decreased by 25% on chronic treatment with 150 mg 5-ISMN per day. Our results show that acute administration of 5-ISMN in either dose (20 mg and 50 mg) exerts unloading effects on the heart and will increase the exercise tolerance. In contrast to the higher dose of 150 mg 5-ISMN per day, chronic treatment with the lower dose of 60 mg 5-ISMN daily will not result in drug tolerance.

Adult↗
PubMed1983

Long-term treatment of patients with coronary heart disease using isosorbide dinitrate, nifedipine and molsidomine.

1. After initial acute administration of 20 or 60 mg ISDN, 2 mg molsidomine and 20 mg nifedipine, a clear effect on the circulation and an increase in work tolerance is detectable. 2. Following 4 weeks' treatment with 3 X 20 mg ISDN, there is no essential loss of action in the venous branch or with respect to working capacity. 3. After 4 weeks' treatment with 3 X 60 mg ISDN, the improvement in working capacity is partially retained, but the action on the venous branch is significantly poorer. 4. During 4 weeks' treatment with 3 X 20 mg nifedipine, there is no essential loss of action in the arterial or venous branches, or with respect to working capacity. 5. Our results with continuous high doses of ISDN indicate that high doses should be used only in monitored exceptions.

Adult↗
PubMed1982

[Continuous registration of micropotentials of the human heart. Initial experiences with a new high resolution ECG amplifier system].

A new ECG-amplifier system for recording cardiac microvolt potentials from the body surface is described. The improvement in signal-to-noise ratio was achieved by using specially designed suction electrodes, which were isolated from each other; by applying parallel signal averaging from four electrode pairs via four low-noise amplifiers; and by conducting the registration in Faraday cage. in 14 normal subjects, 12 patients with coronary heart disease and one patient with surgically corrected ventricular septal defect and pulmonary stenosis, pre-P-potentials (possible sinus node activity), His bundle potentials and ventricular late potentials were recorded with differing degrees of success. Variations of the time intervals to the preceding QRS complex were observed within the S-T segment in six of nine patients with demonstrable ventricular late ventricular late potentials. The advantage of such continuously recording ECG system lies in the highly accurate registration of cardiac micropotentials, particularly with ventricular late potentials that are changing in time, whereas the signal-averaging technique does not provide such possibilities.

Adolescent↗
PubMed1982

[5-isosorbide mononitrate at rest and on exercise in coronary heart disease: acute and long-term effect].

Haemodynamic effects of 5-isosorbide mononitrate (5-ISMN) were studied at rest and on exercise in 31 patients with angiographically confirmed coronary heart disease. A decrease in arterial blood pressure and mean pulmonary artery pressure without significant change in heart rate, cardiac output and stroke volume occurred both at rest and on exercise after 20 mg of 5-ISMN to 12 patients. Administration of 50 mg 5-ISMN to 19 patients achieved greater decrease in mean pulmonary artery pressure; cardiac output and stroke volume were highly significantly reduced at rest, while on exercise both cardiac output and stroke volume remained unchanged. Ten patients, in whom after a single dose of 50 mg 5-ISMN the mean pulmonary artery pressure at rest and on exercise had decreased 28% and 45%, respectively, with a definite rise in exercise tolerance, repeat acute administration of a single dose of 50 kmg 5-ISMN produced a fall in mean pulmonary artery pressure at rest by 20% after 50 mg three times daily for four weeks. On exercise the fall was only 14% below the control levels before treatment. In addition, exercise tolerance was reduced. These results indicate that acute administration of 5-ISMN at rest and on exercise decreases cardiac work load. But on chronic administration of high doses, tolerance to the drug may develop.

Adult↗