Biomedical subjects

B Bienstein

Publications and source records attributed to B Bienstein.

3 recordsLinked to original sources

PubMed2001

[Frequency-dependent rise in absolute threshold during DDD-R stimulation--clinical consequences].

HISTORY AND ADMISSION FINDINGS: A 65-year-old female patient had been supplied with a rate-adaptive DDD-R pacemaker system because of symptomatic sick sinus syndrome with insufficient rate increase one year ago (first implantation of a DDD-system had taken place 14 years ago). In addition she had coronary atherosclerosis without relevant haemodynamic changes. Now she was taken into hospital because of dizziness and dyspnoea on exertion, without loss of consciousness. The physical examination showed normal results concerning heart, lungs and vessels. INVESTIGATIONS: During pacemaker control a significant rate-dependent stimulation threshold increase was found (stimulation rate 70-160/min). Similar results were seen in threshold measurements during operation as well as for the ventricular lead implanted in 1982, and for the new electrode just placed in the right ventricle. Several pacemaker controls within 6 months after implanting the new lead showed a significant increase in pacing threshold. TREATMENT AND COURSE: Because of a new rate-dependent increase of pacing threshold the implantation of a further ventricular lead became necessary. Again a rate dependent threshold increase during and immediately after surgery was detected. This time the programming of the pacemaker allowed a good safety interval because of a generally low stimulation threshold. CONCLUSIONS: This case report demonstrates a rate-dependent rise in threshold on DDD-R stimulation. It clearly shows that this rise occurred more often at high than at low rates of stimulation, but there were marked individual differences. There was no clear correlation between cycle length and the interval from implantation to the investigation. Further investigations including stimulation with various cycle lengths should be carried out in patients at high risk. Furthermore, the development of modern pacemaker systems with autocapture might help to solve this problem.

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PubMed1993

[Reproducible ventricular flutter during programming of a DDD pacemaker].

A bipolar DDD pacemaker system was implanted in a 51-year-old woman with a 2 degrees (Mobitz type) atrioventricular block. The first postimplantation control was unremarkable, but she collapsed 9 weeks later with dyspnoea, tachycardia and profound perspiration. Ventricular flutter occurred twice during routine ambulatory pacemaker function tests one week later. The first episode was terminated by a precordial blow with a fist, but the second required electrical defibrillation. During the subsequent hospitalization abnormal electrolyte balance and digitalis intoxication were excluded. Left-heart catheterization with coronary angiography showed normal left-ventricular function at rest and normal coronary arteries. There was no evidence for an arrhythmogenic right ventricle. Electrophysiological testing with programmed ventricular stimulation provoked ventricular tachycardia with torsade de pointes and transition to ventricular fibrillation. Antiarrhythmic treatment with sotalol, 160 mg twice daily by mouth, failed to suppress the episodes of torsade de pointes. But further programmed ventricular stimulation was uneventful after the sotalol dosage had been increased to 160 mg three times daily.

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PubMed1993

[Congenital fistulas of the coronary arteries. A review with case presentations].

Coronary artery fistulas are rare atypical communications between a coronary artery and a cardiac chamber or other great vascular structure and usually congenital in origin. Many are detected accidentally by the use of coronary angiography. These fistulas often have minor hemodynamical significance and the course is primarily from the proximal left coronary artery to the pulmonary artery. Though symptoms are rare they should be observed carefully in aspect of possible complications. In contrast sometimes coronary artery fistulas are found when searching for the cause of cardiac murmurs or clinical symptoms. Great amounts of shunted blood can result in cardiac volume overload and myocardial ischemia may occur by coronary steal. Surgical closure of these fistulas is the treatment of choice. In our laboratory we found in a series of 3,000 coronary angiographies a 53 year old man with an abnormal communication from the right coronary artery to the right atrium and a 68 year old woman with a fistula from the proximal left anterior descending artery to the pulmonary artery.

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