Biomedical subjects
Publications and source records attributed to W Steinbrunn.
Natural history of an aneurysm at the bifurcation of the left coronary artery is reported. A gradual increase in its size occurred over an 18-year period until it was a huge and partially thrombosed sac. It was associated with ectasia of the right coronary artery, aneurysms of the left subclavian artery and thoracic aorta, and calcified dilatations of the branches of the celiac trunk.
A patient with successful implantation of an internal mammary artery graft in the left anterior descending coronary artery complained of residual but different anginal pain after operation. Ischemia was demonstrated during a manual stress test. Angiography revealed anomalous origin of the thyrocervical trunk from the internal mammary artery. Angina and ischemia disappeared after the trunk was ligated.
The effects of the antiaggregant substance ticlopidine and of the anticoagulant acenocoumarol on patency rates of aorto-coronary bypass grafts were compared in a prospective randomized trial. Ticlopidine, 250 mg b.i.d. was administered orally from the first postoperative day till angiography, while anticoagulation with acenocoumarol was initiated on the second to third postoperative day. Side-effects of ticlopidine were rare and patient management with the standard dosage of this drug was easier than oral anticoagulation. From an initial group of 166 randomized patients 149 completed the trial by coronary angiography three months postoperatively. The 78 patients in the ticlopidine group showed a compliance of 85%. The average prothrombin time in the 71 patients receiving acenocoumarol was 26.9%. Detailed statistical analysis of the two study groups revealed no reason to doubt the correctness of randomization. Coronary angiography showed an average patency rate per patient of 84% with ticlopidine and of 82% with acenocoumarol. This and various other measures of graft occlusion did not reveal any substantial difference in graft patency of patients receiving ticlopidine or acenocoumarol. It is concluded that ticlopidine may well be used instead of anticoagulants for prevention of postoperative occlusion of aorto-coronary bypass grafts.
To evaluate the degree of physical activity in hemodialysis patients, working capacity was assessed by bicycle ergometry in 16 hemodialysis patients (mean age 47 +/- 12 [SD] years). The mean length of dialysis treatment was 21 +/- 17 months. The laboratory and clinical findings were as follows (mean values +/- SD): urea 34 +/- 6 mmol/l; creatinine 1127 +/- 169 mumol/l; potassium 5.7 +/- 0.63 mmol/l; calcium 2.25 +/- 0.22 mmol/l; phosphate 1.76 +/- 0.54 mmol/l; hemoglobin 8.54 +/- 1.02 g/dl; hematocrit 26.1 +/- 2.9%; blood pressure 140 +/- 18/86 +/- 9 mm Hg; nerve conduction velocity 39.5 +/- 6.5 m/sec. Mean working capacity was 58 +/- 31 W (41 +/- 24% of normal values) and the specific working capacity (watts/kg body weight) was 0.79 +/- 0.54. The duration of exercise testing was 4.9 +/- 2 min. The ergometry had to be discontinued because of the following reasons: leg fatigue (10 patients); general fatigue (3); dyspnea (1); attainment of maximal heart rate (2). The maximal blood pressure during exercise testing was 149 +/- 21/86 +/- 14 mm Hg and the maximal increase in heart rate 117 +/- 34 beats/min. In patients treated with a beta-blocker agent for hypertension, maximal increase in blood pressure was comparable to normotensive patients. There was a negative correlation between working capacity and the age of the patients (r = 0.77; p less than 0.01). A positive correlation was found between working capacity and the serum creatinine level (r = 0.52; p less than 0.05).
Sudden death in Wolff-Parkinson-White syndrome (WPW) is related to a very fast ventricular response to spontaneous atrial fibrillation (AF) conducted via accessory pathway (AP). The effect of oral amiodarone was studied in 12 patients with WPW syndrome and life-threatening rapid ventricular response via an AP during spontaneous AF. The effective refractory period of the AP in the anterograde direction was 280 ms or less during control study in all patients. After amiodarone therapy, the effective refractory period remained 280 ms or less in 7 of the 12 patients. During incremental atrial pacing, the longest atrial pacing cycle length that produced block over an AP ranged from 200 to 310 ms (mean 261 +/- 42) during the control period and 240 to 980 ms (mean 377 +/- 198) after amiodarone therapy. During AF the shortest ventricular response via the AP could be measured in 10 of 12 of the patients both before and after amiodarone treatment and ranged from 200 to 290 ms (234 +/- 30) and 250 to 500 (mean 302 +/- 75), respectively (p less than 0.01). The average RR interval during AF before and after the drug ranged from 200 to 390 ms (mean 280 +/- 55) and 280 to 650 ms (mean 396 +/- 116), respectively (p less than 0.01). Thus, the safety of amiodarone in the WPW syndrome should be established by electrophysiologic studies and induction of AF, because amiodarone is not protective in all patients with WPW.
A series of follow-ups were carried out in 947 patients who had 12 to 28 months previously (average 16.6 months) undergone a period of rehabilitation at this clinic in Gais . 17 patients were not traced, but from the remaining 930 patients, 35 (3.8%) had died of cardiac disorders, 21 had had nonfatal infarctions, and 51 patients had undergone aortocoronary bypass operation by the follow-up period. The prevalence and grade of angina pectoris (NYHA functional classification) in 816 patients from whom data was obtained remained unchanged. Even after exclusion of all patients with reinfarction or bypass surgery, there was no increase in the severity of angina pectoris in the remaining 752 patients. 705 patients had returned to work, 555 of whom were still in full employment and 118 part-time , while 32 remained active housewives. From the remaining 112 patients who were not working, 55 had retired. In conclusion, a stable course and high grade of employment were observed during the first year after infarction in patients who had undergone a course of rehabilitation at this clinic.
The effect of phentolamine was studied in 5 patients with pulmonary hypertension, of whom 3 had primary pulmonary hypertension and 2 had secondary pulmonary hypertension after pulmonary embolism. They received intravenous phentolamine in doses of 0.5 mg/min to 2 mg/min (i.e. up to a total dose of 27.5 mg in 25 minutes) during diagnostic cardiac catheterization. Under phentolamine infusion only 2 of the 3 patients with primary pulmonary hypertension showed a significant rise in cardiac index, from 1.4 to 2.0 and from 1.8 to 2.2 l/min/m2 respectively, a fall in pulmonary artery mean pressure from 100 to 93 and from 42 to 33 mm Hg respectively, and a decrease in pulmonary vascular resistance from 2950 to 1900 and from 1160 to 725 dyn X sec X cm-5 respectively. In 1 patient with primary, and 2 patients with secondary pulmonary hypertension, infusion of phentolamine had no effect. Interestingly, in the two patients with primary pulmonary hypertension who responded well to phentolamine the condition was very severe. It appears that even in cases with very advanced primary pulmonary hypertension there is a vasospastic component which can be influenced by vasodilators.
A composite picture of the natural history of coronary disease has emerged from a large prospective study of patients who were followed for periods ranging from seven to 13 years. The course of the disease as reflected in the data appears more favorable than that predicted from retrospective studies, with respect to both mortality and quality of life.
Atrioventricular (AV) conduction disturbances in patients (pts) with sick sinus syndrome (SSS) are well known, but sinus node function (SNF) in AV block is not well documented. We therefore performed electrophysiological tests to evaluate SNF in 30 pts with high-degree AV block (group 1) and AV conduction in 15 pts with SSS (group 1). These measurements were repeated after vagolysis with atropine in group 2. In group 1 ergometry was performed if the electrophysiological SNF tests were abnormal. Results (mean +/- 1 SD) for group 1 were: sinus node recovery time (SNRT) 1184 +/- 473 ms, corrected SNRT (cSNRT) 337 +/- 394 ms. In 3 pts SNRT or cSNRT was abnormal. In these 3 pts the response of sinus rate to exercise was insufficient. In group 2 SNRT before and after atropine was 2345 +/- 822 ms and 1558 +/- 815 ms respectively (p less than 0.05), cSNRT 1285 +/- 965 ms and 954 +/- 832 ms (n.s.), sinoatrial conduction time 319 +/- 283 ms and 150 +/- 149 ms (n.s.), and Wenckebach point 532 +/- 178 ms and 383 +/- 68 ms (p less than 0.01). His-ventricle time was 48 +/- 5.8 ms. In 6 of these 15 pts impaired AV-conduction was present (defined as Wenckebach point below 500 ms), but normalized in 4 pts after atropine. We postulate that persistence of abnormal SNF and AV conduction after vagolysis is an argument for organic binodal disease. This occurs with equal frequency in both groups in about 10% of patients. Increased vagal tone is common in SSS and uncommon in AV block. In patients with SSS the frequent additional AV conduction delay must be taken into consideration when atrial pacing is considered.
For the purpose of coronary angioplasty (PTCA) coronary stenoses over 80% usually can only be passed with very small catheters. We therefore developed an instrument with a very small tip-diameter and two balloons of different diameters arranged in line. In 9 cases primary success has been achieved and the degree of stenoses reduced from 89% to 22%. The gradient of 58 mm Hg was only 11 mm Hg after PTCA. When used with caution, the advantages of this catheter in high-degree coronary stenoses is obvious.
Six patients treated with a combination of amiodarone and class I antiarrhythmic agents for a minor arrhythmia developed atypical ventricular tachycardia "en torsades de pointe". All patients had QT-interval prolongation in the ECG. Combined administration of quinidine and amiodarone in a normal volunteer resulted in an increase in plasma quinidine concentration and in QT prolongation, thus confirming the clinical observation of a clinically relevant interaction between the two drugs.
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False aneurysms of the left ventricle after myocardial infarction arae the result of perforation, which usually require early surgical treatment. The clinical features are not characteristic. The chest x-ray may provide important evidence for the diagnosis. Non-invasive diagnosis is possible by means of echocardiography and computer tomography; it is confirmed by angiocardiography. The authors experience with nine cases is described.
In coronary angioplasty (PTCA) stenoses over 80% can usually be passed with very small catheters only. To pass stenoses with different catheters during one procedure may be dangerous because of dissection. We therefore developed an instrument with very small tip-diameter and two balloons of different diameters in series. In 9 cases primary success was achieved and the degree of stenoses reduced from 90% to 23%. The gradient was 58 mmHg and remained only 11 mmHg after PTCA. When used with caution, the advantage of this catheter in high degree coronary stenoses is obvious.
The acute and long-term hemodynamic benefit from atrial synchronization in ventricular (VAT) pacing has been investigated at rest and during exercise in 10 patients undergoing pacemaker implantation for complete A-V block. The results were compared to conventional (VOO) ventricular stimulation at rates of 70 BPM and 96 BPM. Cardiac index (CI) in VAT-pacing increased at rest by 8% and during exercise by 15% more than with VOO pacing (p less than 0.01). No significant change between the two different rates of asynchronous pacing was observed. CI at rest and during exercise was unchanged after 10 weeks of VAT-pacing. CI is regulated by change of stroke volume in VOO-pacing and by heart rate only with VAT-pacing. In contrast to earlier results with asynchronous ventricular pacing, the hemodynamic benefit of pacing in an atrial synchronized mode is long-lasting. Physiologic mechanisms regulate hemodynamics during exercise and in heart failure.
45 patients with uncomplicated myocardial infarction and on no cardiac drugs underwent an exercise test and 24-hour monitoring 53 (range 22-80) days after the acute event before entering a 4-week rehabilitation program. These same tests were repeated 21 days later. Severe ventricular arrhythmias were registered in 14 patients (31%) while monitored on tape, in only 1 patient during exercise. Arrhythmias were more common in patients with ST-depression during exercise (38%) and in patients with reduced work capacity (42%). Non-smokers had no severe arrhythmias. The rehabilitation program had no influence on these findings. Arrhythmias after myocardial infarction correlate with work capacity and myocardial ischemia.
229 unoperated male patients with at least 50% obstructive lesions of at least one major coronary artery were followed for 1604 patient years (7 years per patient). 88 deaths were observed during this period. 54 of the 79 cardiac deaths (68%) were sudden. The percentage of sudden cardiac death was 74% for three-vessel disease, 83% for left main lesions, 81% for ejection fraction (EF) over 0.50 and 75% for EF under 0.36. It is concluded that sudden cardiac death is likely to occur just as well with normal EF (but three-vessel or left main disease) as with severely reduced EF.