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Biomedical subjects

M Pfisterer

Publications and source records attributed to M Pfisterer.

At least 55 records · Page 3Linked to original sources
PubMed1998

Selective versus non-selective antiarrhythmic approach for prevention of atrial fibrillation after coronary surgery: is there a need for pre-operative risk stratification? A prospective placebo-controlled study using low-dose sotalol.

AIM: This study evaluated the advantages of 'selective' over 'non-selective' antiarrhythmic prevention of atrial fibrillation after coronary surgery based on a new risk prediction algorithm. METHODS AND RESULTS: In a retrospective analysis of a prospective randomized trial, a model for risk prediction was determined based on clinical data of the control group (A; n = 107) and tested in a test group (B; n = 107, treated with low dose sotalol). Using this algorithm, the effect of a 'selective' antiarrhythmic approach in high-risk patients was compared to a 'non-selective' approach, where all patients were treated. In total, 75 (35%) patients developed atrial fibrillation and 14 (7%) side-effects led to discontinuation of study medication. Based on the risk prediction algorithm, 36% of group A patients were classified as high-risk patients with an incidence of atrial fibrillation of 76% compared to 26% in low-risk patients (P < 0.0001). The selective approach, i.e. treatment of high-risk patients only reduced the incidence of atrial fibrillation from 76% to 50% (P = 0.0295) compared to a reduction from 44% to 26% (P = 0.0065) when all patients were treated. More importantly, with the non-selective approach 100% of patients were exposed to the possible side-effects of sotalol and costs compared to 24% only with the selective approach (P < 0.0001). CONCLUSIONS: Thus, a selective approach based on a clinical risk prediction algorithm should improve the cost-effectiveness and safety of low-dose sotalol in the prevention of atrial fibrillation after coronary bypass surgery.

Adult↗
PubMed1998

Dobutamine stress echocardiography to detect inducible demand ischemia in anesthetized patients with coronary artery disease.

BACKGROUND: A cardiac risk stratification test that can be performed during operation would be expected to give valuable information for the therapeutic management of patients who need urgent noncardiac surgery. This study was designed to evaluate the feasibility and safety of a dobutamine-atropine stress protocol to detect inducible demand ischemia in anesthetized patients. METHODS: A standard dobutamine-atropine stress protocol was performed in 80 patients with severe coronary artery disease during fentanyl-isoflurane anesthesia. Biplane transesophageal echocardiography and 12-lead electrocardiography were used to detect induced ischemia. After dobutamine testing, esmolol, nitroglycerin, or both were used to revert ischemia and any hemodynamic changes, as appropriate. RESULTS: The protocol detected inducible ischemia or achieved the target heart rate in 75 of the 80 (94%) patients. None of the prospectively defined adverse outcomes, such as cardiovascular collapse, severe ventricular arrhythmia, persistent (> or =5 min) ischemia, or hemodynamic instability, occurred in any of the patients. Ischemia was induced and detected in 73 of the 80 (91%) patients. CONCLUSION: Dobutamine stress echocardiography is feasible in anesthetized patients with severe coronary artery disease. The lack of serious complications and the high sensitivity to detect inducible ischemia in this patient population provide the basis for further evaluation of the safety and diagnostic value of dobutamine stress echocardiography during general anesthesia in larger studies of patients at risk for coronary artery disease undergoing noncardiac surgery.

Anesthesia, General↗
PubMed1998

Predictors of loss of atrioventricular synchrony in single lead VDD pacing.

OBJECTIVE: To evaluate maintenance of proper VDD function, defined as persistence of sinus rhythm with atrial synchronous ventricular pacing, and to define factors predicting failure of the VDD mode in patients with atrioventricular (AV) block and normal sinus function. DESIGN: Observational study in 86 consecutive patients (mean (SD) age 74 (12) years; 38 women, 48 men) with single lead VDD pacing systems (Intermedics Unity, n = 66, Medtronic Thera VDD, n = 20), implanted for high degree AV block with documented normal sinus node. Pacemaker function was assessed by event counters, telemetric measurements, and Holter recordings. Demographic, radiological, and pacing variables were correlated with loss of proper VDD function. RESULTS: During a mean (SD) follow up of 10 (10) months (range 1-37), sinus rhythm and atrial triggered ventricular pacing were maintained in 70 of 86 patients (81%). Atrial undersensing was observed in nine patients, lead migration in two, atrial fibrillation in three, and symptomatic sinus bradycardia in two. Univariate predictors of loss of proper VDD function were: low position of the atrial dipole relative to the carina (> or = 6 cm; p < 0.01) during fluoroscopy; and maximum programmable atrial sensitivity of the pacemaker (p = 0.03). In a multivariate analysis, only dipole position remained predictive of outcome (p < 0.02). Not predictive were sex, age, symptoms before pacemaker implantation, cardiothoracic ratio or dilatation of individual heart chambers on chest x ray, side of device implant, and P wave amplitude at implant. CONCLUSIONS: To maintain proper VDD function in the long term, a low anatomical dipole position relative to the carina should be avoided. Electrical guidance of dipole positioning does not seem to influence long term outcome.

Adolescent↗
PubMed1998

Significance of Supraventricular Tachyarrhythmias After Coronary Artery Bypass Graft Surgery and Their Prevention by Low-Dose Sotalol: A Prospective Double-Blind Randomized Placebo-Controlled Study.

BACKGROUND: The single most frequent complication after coronary artery bypass graft surgery is the occurrence of supraventricular tachyarrhythmias leading to a prolonged hospital stay. Although several drugs have been used to treat these arrhythmias, effective prevention was only possible with beta-blocking drugs in selected patients. It was, therefore, the aim of the present study to evaluate the significance of supraventricular tachyarrhythmias in presence of today's cardioprotective management in a broad spectrum of patients and to assess the possible preventive effect and safety of low-dose sotalol after coronary artery bypass graft surgery. METHODS AND RESULTS: In a prospective randomized double-blind placebo-controlled trial, 220 consecutive patients referred for elective coronary artery bypass graft surgery were randomized to 80 mg sotalol twice daily (n = 110) or matching placebo (n = 110) for 3 months with the first dose given 2 hours before surgery. There were no significant differences in baseline characteristics between the two groups. Low-dose sotalol reduced the rate of supraventricular arrhythmias from 43% (placebo) to 25% (sotalol, P <.01), which was atrial fibrillation in 83%, flutter in 7%, and other supraventricular arrhythmias in 10%. Only 7% of all arrhythmias were observed after day 9. Hospital stay was 11 +/- 4 days in patients with supraventricular arrhythmias versus 9 +/- 2 days (P <.001) in patients without. On the fourth postoperative day, heart rate was lower in the sotalol group (75 +/- 12 versus 86 +/- 14 beats per min; P <.0001), but QTc was not significantly prolonged (sotalol, 0.44 +/- 0.03; placebo, 0.43 +/- 0.03; P, ns). Study medication had to be discontinued due to side effects in 6.4% of sotalol and 3.6% of placebo patients (P, ns), but relevant side effects occurred only in two sotalol patients late after surgery. CONCLUSIONS: These data show that without antiarrhythmic therapy the incidence of supraventricular arrhythmias after coronary artery bypass graft surgery is high (43%) and that supraventricular arrhythmias were associated with a prolonged hospital stay (+/-2 days). Prophylactic treatment with low-dose sotalol reduced the incidence of supraventricular arrhythmias significantly (by 40%), thereby reducing overall hospital stay in treated patients. Because more than 90% of all supraventricular arrhythmic episodes occurred within 10 days after surgery and considering the small proarrhythmic effect of sotalol late after surgery, prophylactic treatment with sotalol may be recommended for the first 10 postoperative days to safely reduce supraventricular tachyarrhythmias.

Journal Article↗
PubMed1998

Safe use of platelet GP IIb/IIIa inhibitors.

The platelet membrane glycoprotein IIb/IIIa receptor inhibitor abciximab is used for the treatment of patients undergoing high-risk percutaneous coronary interventions and is used in approximately one third of coronary interventions in the United States and a growing number of procedures in Europe. Recent clinical trials have shown that this potent antiplatelet agent significantly reduces the incidence of death and nonfatal myocardial infarction and the need for revascularization. With expanding experience since the commercial release of abciximab in February 1995, several strategies to enhance the safety of abciximab have emerged. In particular, new data confirm that the risk of bleeding--identified as a concern in the original EPIC trial--can be substantially reduced through the use of low-dose adjunctive heparin, early sheath removal, and fastidious postprocedure vascular access site care. Other recommendations for enhancing the safety of potent antiplatelet agents in a variety of clinical situations are provided. The following article reflects insights regarding the safety of glycoprotein IIb/IIIa inhibitors expressed by a group of international experts convened in Davos, Switzerland, February 16, 1997. This report attempts to review clinical progress to date, formulate recommendations, and map out potentially fruitful lines of inquiry for future investigation.

Abciximab↗
PubMed1997

The inverse Nehb J lead increases the sensitivity of Holter electrocardiographic monitoring for detecting myocardial ischemia.

A major reason for the relatively low sensitivity of Holter electrocardiography (ECG) for detecting ischemia is that the sensitivity of bipolar leads used for Holter ischemia monitoring has not been systematically evaluated, making lead selection difficult. Therefore, this study evaluated the sensitivity of 6 bipolar Holter leads for detecting ischemia during percutaneous transluminal coronary angioplasty. Seventy-five patients, each of whom had > 1 mm ST-segment elevation on an intracoronary electrocardiogram from the myocardium distal to the stenosis during balloon occlusion, were studied for the occurrence of > or = 1 mm ST-segment elevation or depression on the simultaneously recorded Holter leads II, III, aVF, CM5, CR4, and inverse Nehb J. The study found that the inverse lead Nehb J provided a significantly higher overall sensitivity for detecting myocardial ischemia than Holter leads II, III, aVF, CM5, and CR4. Also, the use of inverse lead Nehb J significantly increased the sensitivity of 2- and 3-lead Holter ischemia monitoring. These findings were based on a significantly higher sensitivity of inverse lead Nehb J for detecting ischemia induced by transient occlusion of the left anterior descending coronary artery and a slightly higher sensitivity for detecting ischemia induced by occlusion of the left circumflex coronary artery. None of the bipolar leads studied provided a very high sensitivity for detecting ischemia induced by occlusion of the right coronary artery. These findings show that adequate lead selection can increase the sensitivity of Holter ischemia monitoring. Furthermore, the lack of a highly sensitive lead for detection of inferior ischemia indicates that further evaluation of bipolar leads is warranted.

Angioplasty, Balloon, Coronary↗
PubMed1997

[Survived sudden cardiac death in aortic stenosis and Wolff-Parkinson-White syndrome: Differential diagnosis and therapy].

Based on a case of a 72 year old woman with hemodynamically non-significant aortic stenosis. WPW-syndrome and out-of-hospital cardiac arrest, the diagnostic assessment and differential diagnosis of potentially fatal arrhythmias are discussed. In particular, the incidence of supraventricular and ventricular arrhythmias in patients with WPW-syndrome, their prognostic impact and therapeutic options are outlined.

Aged↗
PubMed1997

[Severe congestive heart failure as a medical emergency].

Acute severe heart failure is one of the leading causes of emergency hospitalization in Switzerland. The decompensation often occurs in the setting of preexisting heart failure. A precise diagnosis is of paramount importance because of the bad prognosis of this disease, and because there is a broad therapeutic armamentarium which can significantly modify the disease process. Besides the physical examination, echocardiography is the most helpful additional examination in these patients. The therapeutic strategy is to eliminate causes and precipitating factors, to assure blood and oxygen supply to the organs, to optimize cardiac work, to normalize intravascular and secondarily extravascular volume, to treat arrhythmias and to combat neurohumoral activation. The World Health Organisation and the European Society of Cardiology have published guidelines providing useful algorithms for diagnosis and treatment.

Acute Disease↗
PubMed1997

Long-term prognosis of young patients after myocardial infarction in the thrombolytic era.

BACKGROUND: Myocardial infarction (MI) in young adults is a rare event. In the Framingham study, the 10-year incidence rate of MI per 1,000 was 12.9 in men 30-34 years old. Overall, 4-8% of patients with acute MI are < or = 40 years old. HYPOTHESIS: It was the purpose of this study to assess the in-hospital and long-term morbidity and mortality in patients < or = 40 years old with acute myocardial infarction compared with older patients in the thrombolytic era. METHODS: A consecutive series of 75 patients aged < or = 40 years (mean 35.0 +/- 4.8) with acute myocardial infarction was compared with an equally sized group of patients aged > 40 years (mean 65.1 +/- 9.8). RESULTS: Thrombolysis or direct percutaneous transluminal coronary angioplasty was performed in 52 versus 24% (p = 0.0004) and 5.3 versus 2.7% (p = NS) in younger and older patients, respectively. Significantly fewer young patients had multivessel disease (28 vs. 64%, p < 0.004). No in-hospital mortality was observed in patients with reperfusion therapy irrespective of age. After a mean followup time of 47 +/- 35 months, cardiac mortality was 0 and 11% (p < 0.03), respectively, in young and older patients with, and 3 versus 24% (p < 0.02) without reperfusion therapy, respectively. In addition, significantly fewer patients in the younger age group developed recurrent angina pectoris (12 vs. 39%, p = 0.0004) or congestive heart failure (9 vs. 34%, p = 0.0005) irrespective of reperfusion therapy. CONCLUSION: Our observations demonstrate that long-term prognosis after myocardial infarction in young patients is excellent in the thrombolytic era.

Adult↗
PubMed1997

Noninvasive stress testing of myocardial ischemia: comparison of GRE-MRI perfusion and wall motion analysis to 99 mTc-MIBI-SPECT, relation to coronary angiography.

In the evaluation of ischemic heart disease only MR imaging seems to have the potential to assess myocardial perfusion, function, and coronary morphology on a single instrument. The aim of this study was to assess the feasibility of a stress test with dipyridamole (0. 56 mg/kg) to analyze myocardial perfusion by Gd first-pass enhancement in ultrafast gradient-recalled-echo MRI (perf-MRI), and wall motion by cine gradient-recalled-echo MRI (Cine-MRI) in one imaging session. Twelve patients underwent complete rest and stress studies; satisfactory MR images were acquired in 10 patients. By 99 mTc-MIBI-SPECT sensitivities to detect ischemic segments were 66.7 % with Perf-MRI, 80.0 % with WM-MRI and 86.7 % for Perf-WM-MRI (Perf-MRI vs Perf-WM-MRI; p = 0.03). Scar was equally detected with a sensitivity of 91.6 % with either MRI technique. Thus, Perf-Cine-MRI provides complementary information for the management of ischemic heart disease and has a higher sensitivity than Perf-MRI alone.

Contrast Media↗
PubMed1997

Influence of n-6 and n-3 polyunsaturated fatty acids on the resistance to experimental tuberculosis.

It has previously been shown that the n-3 polyunsaturated fatty acids (PUFAs) eicosapentaenoic acid (20:5(n-3)) and docosahexaenoic acid (22:6(n-3)) possess antiinflammatory properties and can interfere with immune functions. To evaluate whether this would affect resistance to infection, we studied the influence of different types of fatty acids (FAs) on experimental tuberculosis in an animal model. Three groups of 26 weanling guinea pigs were fed isocaloric diets with 26 cal% fat that differed in FA composition with respect to saturated FAs, linoleic acid (18:2(n-6)), eicosapentaenoic acid (20:5(n-3)), and docosanexaenoic acid (22:6(n-3)) as follows: (1) reference (REF) group: 14.8 cal% saturated FAs and 2.8 cal% linoleic acid; (2) n-6 group: 4.6 cal% saturated FAs and 15.4 cal% linoleic acid; (3) n-3 group: 6.3 cal% saturated FAs, 10 cal% linoleic acid, 1.4 cal% eicosapentaenoic acid, and 0.9 cal% docosahexaenoic acid. After 13 weeks, 18 animals from each group were intramuscularly injected with 180 colony-forming units (CFU) Mycobacterium tuberculosis strain H37Rv. Eight noninfected animals per group served as controls. Seven weeks later, the mean number of mycobacteria recovered from the spleens of the n-3 group (log 4.34 CFU, standard error of the mean [SEM], 0.12) was significantly higher than from the REF group (log 3.90 CFU; SEM, 0.15) and the n-8 group (log 3.93 CFU; SEM, 0.13; P < .05). In addition, the Root Index of Virulence (RIV) showed the most pronounced progression of the disease in the n-3 group. The mean size of the tuberculin reaction was larger in the n-3 group than in the other groups (P < .05). There was no significant difference between the n-6 group and the REF group. We conclude that supplementing the diet with n-3 FAs eicosapentaenoic acid and docosahexaenoic acid can affect resistance to M tuberculosis, whereas supplementing with n-6 FAs does not.

Animals↗
PubMed1996

[Risk stratification following myocardial infarct].

In recent decades, early mortality of acute myocardial infarction has decreased from above 30% to below 10%. Many survivors of acute myocardial infarction are at increased risk for cardiac death and/or nonfatal recurrent ischemic events. This has not changed with the introduction of thrombolysis. How can high risk patients be identified who would benefit from coronary revascularization and/or from antiarrhythmic treatment? Based on clinical findings such as a large infarction, infarction of the anterior wall, congestive heart failure, cardiogenic shock during the acute phase, post-infarct angina and a history of previous infarctions, high risk patients who should undergo coronary angiography and--if feasible--revascularization can be defined. Patients with symptomatic arrhythmias should receive medical or interventional antiarrhythmic treatment. All patients who are clinically considered not to be at high risk should undergo risk stratification with signal averaged ECG, non-invasive stress testing and non-invasive quantification of left ventricular function. In the presence of late potentials, ischemia during stress testing and impaired left ventricular function, further evaluation with Holter ECG or an electrophysiologic study and coronary angiography is indicated. In infarct survivors over 75 years old, the therapeutic goal is improvement of quality of life, i.e. relief of symptoms, rather than improvement of prognosis. Invasive procedures should therefore be considered only in individual patients. However, in all postinfarct survivors the assessment and treatment of cardiovascular risk factors and secondary medical prevention is mandatory.

Adult↗
PubMed1996

[Supraventricular tachycardias: mechanism, diagnosis and therapy].

Most of the paroxysmal forms of supraventricular tachycardia are reentry tachycardias in origin with either an AV-nodal reentry (AVNRT; approx. 50%) or an AV reentry circuit via accessory pathway (AVRT; approx. 30%) as the anatomical basis of tachycardia. The therapeutic options include either drug therapy or transcatheter radiofrequency ablation. In asymptomatic patients, where supra-ventricular tachycardia or WPW syndrome was documented incidentally, an expectative approach without therapy is usually recommended. However, if frequent tachycardia recurrences or severe clinical symptoms (syncope, pre-syncope make treatment mandatory, medical therapy with either betablockers, calcium antagonists or digoxin should be tried if AV-nodal reentry tachycardia is the mechanism (no evidence of WPW syndrome on the 12-lead ECG). In patients with symptomatic WPW syndrome or drug refractory AV-nodal reentry tachycardia, transcatheter radiofrequency ablation with its good results and low complication rate is the therapy of choice. The treatment modality is particularly indicated in young patients who otherwise would need lifelong drug therapy. In contrast, supraventricular tachycardias with badly defined anatomical substrate, such as multifocal atrial tachycardias or atrial fibrillation, should in the first place be treated medically and not by radiofrequency ablation.

Anti-Arrhythmia Agents↗
PubMed1996

[Drug therapy of cardiac insufficiency: status 1995].

Congestive heart failure is a frequent disorder with an estimated prevalence of 0.4-2% in the general population. Despite recent advances in our understanding of the pathophysiology of this disorder and new developments in its treatment, the prognosis of heart failure remains poor. All patients with heart failure should undergo diagnostic evaluation to determine the type of cardiac dysfunction, establish its etiology and orient treatment. Angiotensin converting enzyme (ACE) inhibitors, diuretics and digoxin are the standard therapy for chronic congestive heart failure caused by systolic dysfunction. ACE inhibitors are indicated in all stages of heart failure, even in asymptomatic patients. Diuretics should be added in the presence of fluid retention. Digoxin remains an important component in the management of refractory symptoms and atrial fibrillation. Symptomatic improvement and reduced morbidity have been shown with all these drugs. However, improved survival has been documented for ACE inhibitors only. Currently, numerous drugs with different mechanisms of action are being evaluated in ongoing clinical trials. Promising results have been published, mainly with beta-receptor blockers and newer positive inotropic substances. Rapidly growing evidence from basic research will advance our understanding of heart failure and hopefully pave the way for new preventive and therapeutic strategies in the near future.

Adrenergic beta-Antagonists↗
PubMed1996

[Intracoronary ultrasound: scientific aspects and clinical possibilities].

The recent development of miniaturized ultrasound devices incorporated at the tip of flexible angiographic catheters permits, for the first time in vivo, visualization of the full circumference of the vessel wall from a single tomographic view, similar to a histological study. Potential advantages of intracoronary ultrasound as compared to coronary angiography include characterization of the intramural anatomy of the vessel wall in normal and atherosclerotic segments as well as quantification of luminal dimensions and severity of stenoses using planimetry even in vessels with complex plaque morphology. Intracoronary ultrasound has therefore been called the new gold standard for vascular imaging. The method has been validated in vitro and in vivo and is highly reproducible. The complication rate of intracoronary ultrasound imaging is low. In addition to research applications, there are several emerging clinical applications for intracoronary ultrasound in the diagnosis of coronary artery disease, for instance for angiographically indeterminate lesions, in the assessment of transplant vasculopathy or in planning and guiding of coronary interventional procedures.

Coronary Angiography↗
PubMed1996

[Assessment of ventricular arrhythmias].

In the evaluation of patients with ventricular arrhythmias, those patients with asymptomatic ventricular arrhythmias, who usually comprise a low-risk population, have to be differentiated from patients with symptomatic ventricular arrhythmias (presyncopal symptoms, syncope, cardiac arrest). In general, patients with asymptomatic ventricular arrhythmias should not be treated with antiarrhythmic drugs; however, patients with recent myocardial infarction and asymptomatic ventricular arrhythmias, which may indicate an increased risk of sudden death, should undergo further risk stratification, since some of them might benefit from preventive antiarrhythmic therapy with a beta-blocking agent of amiodarone. In contrast to asymptomatic patients, patients with symptomatic ventricular arrhythmias are at high risk for sudden death, and, if functional status does not mandate against active therapy, these patients should undergo coronary angiography and electrophysiologic evaluation. Revascularization procedures and specific antiarrhythmic measures such as antiarrhythmic drug therapy, ablative therapy (surgical resection or transcatheter radiofrequency ablation of the arrhythmogenic focus) or the implantation of a cardioverterdefibrillator (ICD) are frequently needed in such patients. Consequently, in this high-risk population, early referral to a cardiac center with an electrophysiologic laboratory is recommended, whereas it should be strongly mandated against empirical antiarrhythmic drug therapy.

Adrenergic beta-Antagonists↗