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Biomedical subjects

D W Behrenbeck

Publications and source records attributed to D W Behrenbeck.

At least 19 recordsLinked to original sources
PubMed1987

Particularities of dual chamber pacemaker therapy in patients after orthotopic heart transplantation.

Since August 1981, 33 orthotopic heart transplantations were performed in our hospital. Three of these patients (9%) had sinus bradycardias with rates as low as 30 beats/min; they were treated by implantation of a dual chamber pacemaker. These patients had two atria as a result of orthotopic heart transplantation, but only the donor atrium was suitable for positioning the atrial lead. In the postoperative period, some nonsurgical complications were observed in one patient who developed atrial fibrillation which we treated with drugs. A cyclosporin-evoked tremor produced several asystoles due to false inhibition by myopotential interference in the VVI mode. During an episode of acute rejection combined with renal insufficiency, loss of atrial and ventricular sensing occurred. The other patients showed no pacemaker-related complications. Our findings in this unique population of pacemaker patients are discussed.

Adult↗
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↗
PubMed1979

[Nitroglycerine in chronic obstructive pulmonary disease (author's transl)].

The effect of 0.8 mg nitroglycerine on haemodynamics and pulmonary functions was examined in 12 patients with chronic obstructive pulmonary disease. Resting heart rate was increased from 72 to 82/min by nitroglycerine, but at rest and on exercise there was only a slight reduction in systolic blood pressure, the diastolic level remaining essentially unchanged. There was a decrease in cardiac index of 16 and 15% at rest and on exercise, respectively. A highly insignificant reduction in mean pulmonary artery pressure occurred both at rest and on exercise. Respiratory variations of pulmonary artery pressure markedly decreased after nitroglycerine and correlated well with airway resistance, which fell by 28%. Pulmonary vascular resistance fell from 188 to 149 dyn.s.cm-5. Vital capacity increased after nitroglycerine as a sign of reduction of pulmonary emphysema. Partial pressure of arterial oxygen and carbon dioxide showed no definite changes at unchanged respiratory rates. Thus nitroglycerine produces a marked improvement in haemodynamics and pulmonary function without any increase in ventilatory distribution abnormalities. These results support the use of nitroglycerine as one of several means of treating chronic obstructive pulmonary disease.

Adult↗
PubMed1979

[Computed axial tomography (cat) in the diagnosis of diseases of the heart and aorta (author's transl)].

Computed axial tomography (CAT) was used in 70 patients with diagnostic problems centering on the heart (47 patients) or the aorta (23). The method proved suitable for the diagnosis, differential diagnosis and serial control of pericardial effusions and also well demonstrated intracardiac tumours. Aortic aneurysms are also easily demonstrated and their extent can be exactly defined. But aortic wall dissection and stenosis of arteries arising from the aorta are not visualized and therefore require angiography.

Adolescent↗
PubMed1979

An approach to direct detection of sinus nodal activity in man.

We are reporting a series of 13 out of a total of 16 patients in whom sinus nodal activity was recorded with the use of intra-atrial electrodes, during diagnostic His-bundle electrocardiography investigations. The protocol consisted of the simultaneous monitoring of the following intra-atrial points: high right atrium, low lateral right atrium, left atrium and the His-bundle electrogram (HBE), which accompanied the detecting sonde placed as a loop in the superior vena cava, with the electrodes facing the sinus nodal area. This permitted an adequate assessment of the sequence of the depolarizing activity. All patients showed sinus nodal potentials preceding the initiation of the P-wave in the surface-EKG or the atrial potential in the high right atrial lead, respectively, in the range of 60 to 270 msec depending upon the functional status of the sinus node in each patient. Such waves were clearly separated from the initiation of the atrial potential by an isoelectric line and showed functional traits compatible with the S-A nodal functions, as many authors have previously reported in experimental animal models. The text contains a review of the relevant literature and discussion upon the diagnostic significance of this method in the assessment of sinus nodal disease.

Adult↗
PubMed1979

[The differential diagnosis of heart failure (author's transl)].

The causes of heart failure may be classified into three groups, hemodynamic causes, disturbances of cardiac rhythm and conduction and diseases of the myocardium. Accordingly the different causes of heart failure are discussed and the technics for diagnosis reviewed. Particular diagnostic problems are mentioned, which may arise in connection with cardiac echinococcosis, atrial myxoma, sarcoid heart disease and myocardial aneurysm.

Arrhythmias, Cardiac↗
PubMed1979

[The direct detection of sinus nodal potentials in man by means of the signal-averaging technique (author's transl)].

In 13 patients in the age range of 34 to 70 years (mean: 53 +/- 10 years), during diagnostic His-bundle investigations, registrations from the sinus nodal area were analyzed with a signal-averaging computer. In 12 patients we were able to get reproducible per-P-potentials with a sino-atrial conduction interval between 56 and 227 ms. The normal sequence of the excitation process from the atrium to the AV node together with the bundle of His and to the ventricles in all patients, and the reproducibility of the signal-averaged pre-P-potentials, which were well outlined from the atrial potential with a reasonable conduction interval, suggest that these signal-averaged pre-P-potentials reflect the sinus nodal activity rather than an ectopic focus. In 5 of 11 comparable cases there was a good correlation between the signal-averaged sino-atrial conduction intervals and those calculated with the extrastimulus technique. In 2 patients this correlation was moderate. The signal-averaging process may be impaired by coarse random noise, frequent atrial or ventricular extrasystoles, and by fluctuations of the baseline of the sinus nodal lead. The fact that the registrations are performed during normal undisturbed sinus rhythm offers a considerable advantage over the extrastimulus technique.

Action Potentials↗
PubMed1978

[Action of molsidomine on haemodynamics at rest and on exercise in patients who have coronary heart disease (author's transl)].

In ten patients with coronary heart disease molsidomine achieved a clear-cut decrease in pre- and after-load of the heart at rest. Due to decreased venous return at rest there was a fall in stroke volume resulting in a fall of systolic and diastolic aortic pressure. But at the same level of standardised exercise, systolic and diastolic arterial pressure and cardiac output were similar with or without molsidomine. Without changing after-load, there was a fall in pulmonary artery mean pressure (P less than 0.005), probably due to an increase in left-ventricular compliance and (or) a fall in pulmonary vascular resistance. A rise in venous capacity or a decrease in venous return during exercise was excluded as a possible mechanism of molsidomine action.

Adult↗
PubMed1978

[Echocardiographic detection of a left ventricular tumor after myocardial infarction (author's transl)].

A mobile left-ventricular tumor was detected by echocardiography in a 28-years-old patient, who has sustained an anteroseptal infarction four years before. The patient was admitted to hospital because of arterial embolism. The echocardiographic finding was validated by left-ventricular angiography. In open-heart surgery a pedunculated tumor was excided, in microscopic study the tumor revealed the findings of an organized thrombus. The echocardiographic and angiographic findings are shown, the echocardiographic differential diagnosis is pointed out.

Adult↗
PubMed1977

[Oesophagosternal and oesophagoapical leads for registration of surface his-bundle potentials (author's transl)].

Theoretically there should be two possibilities of recording His-Bundle potentials from the body surface. Extensive amplifying and signal averaging can improve the signal to noise ratio of the His-Bundle potential. Random noise can be filtered and the periodic signal of the His bundle can be selected. On the other hand improvement of the noninvasive leading conditions could be achieved by positioning of the recording electrodes close to the structure to be investigated and by direction of the surface leading according to the anatomical axis of the bundle of His. For this purpose these new oesophagosternal and oesophagoapical leadings have been developed. The different oesophageal electrode is placed nar the upper cava-right atrial border close to the heart. The indifferent electrode is situated at the xiphisternum or at the apex of the heart. The direction of this lead is close to the direction of the anatomical axis of the His-Bundle. By this means a positive wave within the PR-segment can be registered, which we have called the "HP-wave". In a total of 17 patients these bipolar oesophageal leads were employed, in 12 cases simultaneously with the intracardiac HBE as a reference method. At rest the peak of the HP wave correlated to the maximal amplitude of the intracardiac His spike in more than 90% of patients. 4 patients were investigated by atrial pacing, in 3 cases this correlation could be found, too. Apparently the true His bundle signal can be obtained from the body surface by this new leading system. For improvement of the surface His bundle recordings, we reflect the combination of our noninvasive oseophageal lead with a modified signal averaging system with lesser amplication of the original signal.

Adolescent↗