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Biomedical subjects

D Burckhardt

Publications and source records attributed to D Burckhardt.

At least 73 records · Page 4Linked to original sources
PubMed1986

Withdrawal of the long-acting beta blocker bopindolol is not associated with beta-adrenoceptor supersensitivity.

beta-Adrenoceptor sensitivity after abrupt withdrawal of long-term therapy (5-12 months) with bopindolol (1-2 mg/day), a long-acting beta-adrenoceptor blocking agent with intrinsic sympathomimetic activity, was assessed in five patients with uncomplicated essential hypertension. The chronotropic dose 25 of isoproterenol (CD 25), plasma concentrations of catecholamines, triiodothyronine and thyroxin, plasma renin activity and aldosterone, hemoglobin, hematocrit and oxyhemoglobin dissociation were measured on the last day of bopindolol administration and 1, 2, 3, 6, and 13 days after abrupt replacement by placebo tablets. The chronotropic dose 25 of isoproterenol (microgram/m2) was greater than 25.6 in all patients on the last day of bopindolol therapy. On day 1 in patients who had been taking 2 mg/day of bopindolol, CD 25 remained greater than 25.6 but fell to 12.1 in the one patient who had been taking 1 mg/day. On day 2, CD 25 was 10.19 +/- 2.97 and felt gradually to the lowest value of 3.76 +/- 1.19 on day 13. Throughout the study, plasma concentrations of catecholamines, triiodothyronine and thyroxin, and oxyhemoglobin dissociation remained unchanged. Plasma renin activity and plasma aldosterone, which were suppressed during bopindolol therapy, rose during placebo, coinciding with a fall in hemoglobin and hematocrit. No subjective symptoms of increased beta-adrenoceptor-mediated functions were reported by the patients throughout the whole study period. Therefore, hypersensitivity of beta-adrenoceptor-mediated responses was not demonstrated within the first 13 days after sudden withdrawal of bopindolol.

Adrenergic beta-Antagonists↗
PubMed1986

Non-invasive grading of aortic regurgitation by Doppler ultrasonography.

Doppler ultrasound without concomitant echocardiographic imaging was used to grade isolated aortic regurgitation in 21 patients. The severity of aortic regurgitation was subsequently graded (from 0 to IV) angiographically. A 2 MHz continuous wave Doppler transducer was placed over the apex of the heart and the beam was aimed parallel to the mitral flow by means of acoustic guidance. Mitral pressure half time was calculated from the analogue maximum velocity tracing and it was less than or equal to 60 ms in 10 controls; 50-120 ms in five patients with grade II, 120-160 ms in nine patients with grade III, and greater than or equal to 160 ms in seven patients with grade IV aortic regurgitation. These results indicate that a semi-quantitative grading of aortic regurgitation may be obtained non-invasively with non-imaging Doppler ultrasonography in patients without concomitant mitral valve disease.

Adult↗
PubMed1985

[Use of Doppler ultrasound in cardiac diagnosis].

In cardiac diagnosis Doppler ultrasound provides quantitative data in the assessment of pressure gradient and valve area in stenotic lesions. In atrioventricular valves pressure half-time can be determined. In regurgitant lesions the only method capable of providing quantitative analysis of aortic regurgitation is calculation of forward-to-reverse flow ratio by multigate Doppler. All the other single-gate Doppler or 2-D-echo Doppler methods, such as LV or LA mapping, recording of impaired mitral flow and diastolic/systolic flow ratio, permit only semiquantitative assessment of regurgitant volumes. Finally, semiquantitative analysis of shunt volumes appears possible in children.

Child↗
PubMed1985

Coronary artery bypass grafts. Influence of preoperative risk factors on the late postoperative course.

In order to assess the influence of preoperative risk factors on the late postoperative course, 186 consecutive patients in whom coronary artery bypass graft (CABG) was performed for chronic stable angina (169 men, 17 women, mean age +/- SD 54 +/- 8 years) were followed for an average of 54 (6 to 113) months. The overall five-year survival rate by life-table analysis was 90 +/- 2 percent. The postoperative course was considered favorable in 112 patients (60 percent) in whom angina was absent or improved by at least 2 NYHA classes throughout the entire follow-up, and was unsatisfactory in 74 patients. It was concluded that the late postoperative course of patients with CABG was unfavorably influenced by the presence of two or three risk factors, and a high preoperative cholesterol level was the only single risk factor associated with unsatisfactory outcome.

Adult↗
PubMed1985

[Aortocoronary bypass operation in the elderly patient: favorable long-term course].

Age has been identified as an independent risk factor for coronary artery bypass grafting (CABG). We evaluated, therefore, the perioperative phase and long-term prognosis of all patients over the age of 64 (n = 80), who had been operated on for coronary heart disease at the University Hospital of Basel/Switzerland between 1979 and 1983. These elderly subjects were compared to 80 patients, 50 to 60 years old at the time of CABG, who were matched for degree of angina pectoris, coronary artery disease, left ventricular ejection fraction, sex and year of operation (matched-pairs analysis). Evaluation of long-term prognosis was based on regular clinical controls and on a questionnaire, sent to the patients in June 1984. During the perioperative phase 3 patients over 64 died versus 0 in the group of patients 50-60 years old. There were more complications in the older group (perioperative myocardial infarction 10 vs. 4, pulmonary embolism 2 vs. 0, cerebro-vascular insult 4 vs. 0). Three vs. one permanent pacemaker had to be implanted for irreversible AV-block. The difference in hospital stay, 21 vs. 19 days, was not significant. The cumulative survival rate was in both groups 95% after one year and 86 vs. 92% 5 years after CABG (difference not significant), despite the fact that significantly more elderly patients have had myocardial infarction prior to CABG. After an average follow-up of 28 months, 72% vs. 60% were without thoracic pain; 63 vs. 49% considered themselves in a good overall condition.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1984

Suppression of high-grade ventricular ectopic activity by antiarrhythmic drug treatment as a marker for survival in patients with chronic coronary artery disease.

In order to investigate the relationship between the ease of suppression of complex (frequent multiform, repetitive, and early) ventricular premature beats (VPBs) and subsequent survival, 50 consecutive patients with chronic coronary artery disease (CAD) were followed retrospectively during a mean observation period of 16 months. A total of 124 drug trials were performed using single or combined class I, II, and III antiarrhythmic drugs. Thirty-nine patients were considered "responders" (elimination of Lown classes greater than or equal to IVa and reduction of greater than 30 multiform VPBs to occasional unifocal VPBs during Holter monitoring), whereas in 11 patients VPBs could not be adequately suppressed ("nonresponders"). There were no significant differences in age and congestive heart failure in the two groups. There were three deaths (one sudden) in the 39 "responders" but five deaths (three sudden) in the 11 "nonresponders" (p less than 0.01 for all deaths, p less than 0.05 for sudden deaths). Cumulative probability of survival at 12 months was 0.93 for "responders" and 0.64 for "nonresponders" (p less than 0.005). Significant side effects necessitated drug withdrawal in four patients. Our data suggest that survival in patients with CAD is better when complex VPBs can be suppressed.

Adult↗
PubMed1984

Persisting symptoms despite permanent pacing. Incidence, causes, and follow-up.

Persisting symptoms, consisting of palpitations, dizziness, or syncope, were found in 49 of 570 consecutively followed patients (8.6 percent) with permanent pacemakers (PM). Among 540 patients with ventricular PM, 19 had syncope and 24 dizziness; among 30 patients with dual-chamber PM, five had palpitations and one dizziness. Symptoms were PM-related in 17, caused by tachyarrhythmias in 12, of noncardiac origin in 16, and of unknown origin in four patients. Holter monitoring was necessary for evaluating the persisting symptoms in 36 patients and helpful in 32 studies (89 percent). Symptoms were relieved in all patients with PM-related causes but only in 6/16 patients (38 percent) with syncope or dizziness of noncardiac origin despite various therapeutic measures. In patients with either documented tachyarrhythmias or unknown cause of syncope or dizziness, antiarrhythmic drugs led to symptomatic improvement in 11 of 12 treated patients during an average follow-up of 15 months. We concluded that: (1) persistent syncope, dizziness, or palpitations occurred in 8.6 percent of 570 patients after PM-implantation; (2) symptoms were more frequent but less severe in patients with dual-chamber PM than in those with ventricular PM; (3) tachyarrhythmias as a possible cause of symptoms were found in 25 percent of patients; (4) symptomatic improvement was noted in 28 of 29 patients when a PM-related cause or tachyarrhythmias were treated.

Adult↗
PubMed1984

Clinical evaluation of the St. Jude Medical heart valve prosthesis. A two-year follow-up of 150 patients.

To evaluate the clinical performance of the St Jude Medical bileaflet heart valve prosthesis, we followed 150 consecutive patients (95 male and 55 female patients, mean age 54 years, range 1 to 74 years) for an average of 24 months. These included 74 patients with aortic, 56 patients with mitral, and 20 patients with multiple valve replacement. During the 2 year follow-up, there were a total of four perioperative and seven late deaths, two of which were prosthesis related. Reoperation was necessary in four patients, because of paravalvular leaks in two patients with mitral and one patient with aortic prostheses and because of leaflet dislodgment in one patient with a mitral prosthesis, a postoperative complication that has not been reported previously. The thromboembolic rate per 100 patient-years was 2.6 in aortic and 2.9 in mitral valve replacement, the symptoms being reversible in all patients. All patients were receiving anticoagulant therapy. A total of four complications of anticoagulant therapy (three minor and one fatal) were observed. Significant hemolysis was observed in none of the patients. In patients with dyspnea, the New York Heart Association functional classification was 2.7 +/- 0.8 preoperatively versus 1.3 +/- 0.6 postoperatively. In patients with angina, it was 2.6 +/- 0.6 preoperatively versus 1.03 +/- 0.2 postoperatively. Noninvasive Doppler measurements revealed excellent flow characteristics, values being close to those obtained in natural valves (mean +/- standard deviation of maximal flow velocity: 1.5 +/- 0.5 versus 0.9 +/- 0.1 m/sec in the aortic position; 1.1 +/- 0.3 versus 0.8 +/- 0.3 m/sec in the mitral position).

Adolescent↗
PubMed1983

[Atypical and ischemic chest pain more than a year after aortocoronary bypass].

215 consecutive patients were followed up for more than a year (22 +/- 9 months) after aortocoronary bypass. Recurrence of ischaemic (anginal) and atypical chest pain was assessed: 54% of all patients were completely without pain postoperatively, 76% free of angina and 93% improved by at least one NYHA class. The frequency of severe atypical chest pain was similar pre- and postoperatively (11% and 13%, respectively), but nearly double that of postoperatively severe angina (13% vs 7%, P less than 0.05). Limiting atypical chest pains in patients with pre-operative atypical chest pain was much more frequent postoperatively than in patients who pre-operatively had only angina (30% vs 11%, P less than 0.005). These two patient groups did not differ with respect to age, sex, degree of vessels disease, exercise-induced ischaemia or number and patency of bypasses. Thus, exercise-limiting atypical chest pain can influence the surgical results in up to 30% of patients with pre-operative atypical chest pain (with or without typical angina).

Adult↗
PubMed1983

[Problems of digitalis therapy].

The problems of digitalis therapy are closely related to the intoxication rate of 10-20% in patients under longterm treatment. Awareness of the problems occurring in digitalis therapy should result in a decrease in the intoxication rate. This can be accomplished by (1) information to the patient and (2) information to the physician regarding the pitfalls of digitalis therapy. In this context reference will be made to therapeutic range, mode of digitalization, absorption, conditions associated with decreased digitalis tolerance, conditions involving increased need of digitalis, conditions associated with decreased need for digitalis, and drug interactions.

Digitalis↗
PubMed1983

Evaluation of systolic murmurs by Doppler ultrasonography.

Non-invasive continuous and pulsed wave Doppler ultrasonography was performed in 102 consecutive patients with clinically ill defined systolic murmurs to differentiate between flow murmurs, mitral regurgitation, aortic stenosis, and ventricular septal defect, as well as to assess the severity of aortic stenosis. Diagnoses with the Doppler method were based on velocity, direction, and duration of flow signals and were subsequently verified by cardiac catheterisation in all patients. Multiple evaluations were made in 31 patients. Sensitivity and specificity were 0.87 and 0.77 in mitral regurgitation, 0.9 and 1.0 in aortic stenosis, and 1.0 and 1.0 in ventricular septal defect. In 67 patients the estimation of severity of aortic stenosis using the Doppler technique to calculate aortic pressure gradients from maximum flow velocity was significantly correlated with that determined at catheterisation. It is concluded that Doppler ultrasonography is a highly useful technique for the non-invasive evaluation of clinically ill defined systolic murmurs.

Adult↗