[New onset atrial fibrillation in patients with sepsis]

BACKGROUND

Atrial fibrillation is the most common new onset arrhythmia in patients hospitalized with sepsis; however, there are no specific treatment guidelines and the ideal therapeutic approaches still remain unclear.

OBJECTIVES

To begin with the current state of knowledge concerning the underling mechanisms, the incidence and prognostic impact of new onset atrial fibrillation during sepsis are presented. Then a possible therapeutic algorithm for the special situation of sepsis is derived with respect to the currently existing atrial fibrillation guidelines. Finally necessary future research topics are outlined.

MATERIAL ANS METHODS

A systematic literature search was conducted in MEDLINE. All publications (reviews and studies) relevant for the summary of the current knowledge regarding new onset atrial fibrillation in septic patients were included.

RESULTS

The underlying patchomechanism is primarily systemic inflammation. Approximately 8% of patients with sepsis and more than 20% of patients with septic shock develop new onset atrial fibrillation. The occurrence of atrial fibrillation is associated with increased morbidity and mortality. The necessity of rhythm control therapy is dependent on the hemodynamic stability. The success rate of electrical cardioversion can be increased by the administration of amiodarone. The necessity of systemic anticoagulation is based on the individual risk of thromboembolism.

CONCLUSION

Further research is needed to unveil the optimal therapeutic strategies for patients with new onset atrial fibrillation during sepsis.

[Cardioprotection by thoracic epidural anesthesia? : meta-analysis]

BACKGROUND

Thoracic epidural analgesia (EDA) is thought to provide cardioprotective effects in patients undergoing noncardiac surgery. The results of two previous meta-analysis showed controversial conclusions regarding the impact of EDA on perioperative survival. The purpose of the present meta-analysis was to evaluate, whether thoracic EDA has the potential to reduce perioperative cardiac morbidity or mortality on the basis of available randomized controlled trials.

PATIENTS AND METHODS

A systematic literature search was conducted in medical databases (Med-Line, EBM-Reviews, Embase, Biosis and Biological Abstracts) and relevant clinical trials including patients undergoing noncardiac surgery were evaluated by two independent investigators. All randomized controlled trials investigating the effects of thoracic EDA on perioperative outcome, published from 1980 up to the end of 2008 were included into this quantitative systematic review. Calculations were performed using the statistics program Review Manager 4.1 using a fixed-effects model.

RESULTS

Nine studies with a total of 2,768 patients were included in the meta-analysis. Thoracic EDA did not reduce perioperative mortality [odds ratio (Peto OR): 1.08; 95% confidence interval (CI) 0.74-1.58]. Patients receiving thoracic EDA demonstrated a tendency to a lower rate of perioperative myocardial infarction. However, this effect of thoracic EDA did not reach statistical significance (Peto OR: 0.65; 95% CI 0.4-1.05).

CONCLUSIONS

The present meta-analysis did not prove any positive influence of thoracic EDA on perioperative in-hospital mortality in patients undergoing noncardiac surgery. Furthermore, it remains questionable if thoracic EDA has the potential to reduce the rate of perioperative myocardial infarction.

The effect of propofol and desflurane anaesthesia on human hepatic blood flow: a pilot study

This study tested the hypothesis that propofol is associated with a higher hepatic blood flow in humans compared with desflurane. Using a cross over study design, 10 patients received first propofol and then desflurane, and a further 10 patients received desflurane and then propofol. Blood flow index in the right and middle hepatic veins, stroke volume index and cardiac index were assessed by transoesophageal echocardiography. Mean arterial blood pressure, stroke volume index and cardiac index were the same in both groups. Propofol was associated with significantly greater blood flow index in the right hepatic vein (median (IQR [range]) 199 (146-237 [66-388]) vs. 149 (112-189 [42-309]) ml.min(-1).m(-2); p = 0.005) and middle hepatic vein (150 (122-191 [57-341]) vs. 125 (92-149 [47-362]) ml.min(-1).m(-2); p < 0.001) compared with desflurane. In routine clinical conditions, propofol anaesthesia was associated with significantly greater hepatic blood flow than desflurane anaesthesia.

[Left ventricular diastolic dysfunction. Implications for anesthesia and critical care]

Over the last two decades there has been a growing recognition that cardiac function is not solely determined by systolic but also essentially by diastolic function. Left ventricular diastolic dysfunction is characterized by an impairment of ventricular filling caused either by abnormal relaxation, an active energy consuming process or decreased compliance, which is determined by passive tissue properties of the ventricle. Doppler echocardiography, including tissue Doppler imaging, has emerged as the preferred clinical tool for the assessment of left ventricular diastolic function. Recently the importance of left ventricular diastolic function is increasingly being recognized also during the perioperative period. Newer studies have shown that after cardiopulmonary bypass there is a significant decrease in left ventricular compliance. Experimental studies have demonstrated that sepsis is associated with a decrease in both active relaxation and ventricular compliance. Initial studies are also focusing on therapeutic options for patients with isolated diastolic dysfunction.

Noninvasive diagnosis of coronary artery disease: a comparison between cardiokymographic and electrocardiographic stress testing

Noninvasive cardiokymography has been further developed to be able to record wall motion abnormalities during exercise. The study was designed to evaluate the diagnostic accuracy of stress cardiokymography and electrocardiography in the diagnosis of coronary artery disease. 223 patients were included in a prospective investigation using a newly developed computerized cardiokymography device. Sensitivity, specificity, and positive predictive value were 61, 69 and 90% for exercise cardiokymography, and 57, 74 and 91% for exercise electrocardiography, respectively. There was no statistically significant difference between cardiokymography and electrocardiography. The combination of electrocardiography and cardiokymography did not produce a significant improvement in diagnostic accuracy in comparison to exercise electrocardiography alone.

Is it feasible to monitor total hepatic blood flow by use of transesophageal echography? An experimental study in pigs

OBJECTIVES

Total hepatic venous blood flow is determined by the common hepatic arterial blood flow and the venous outflow from stomach, spleen, pancreas, small intestine, and bowel, collected by the portal vein, and thus represents overall splanchnic perfusion. We investigated whether transesophageal echography (TEE) can provide a method for bedside assessment of hepatic venous blood flow useful as a noninvasive method for measuring splanchnic perfusion in clinical practice.

DESIGN AND SETTING

Experimental study in 15 anesthetized and ventilated pigs in an animal research laboratory.

INTERVENTIONS

TEE-derived calculations of hepatic venous blood flow were compared with liver blood flow measurements using perivascular ultrasound flow probes surgically positioned on portal vein and common hepatic artery. Parameters were determined at baseline and after modulating splanchnic perfusion by either PEEP maneuver (15 cmH2O) or intravenous epinephrine (0.1 microgram kg-1 min-1).

MEASUREMENTS AND RESULTS

Diameter (d) and velocity time integral (VTI) of all three hepatic veins were determined by TEE, heart rate (HR) was derived from electrocardiography and flow subsequently calculated as Q = pi.(d/2)(2).0.57.VTI.HR. Regression analysis of matched TEE and flow probe values showed a significant linear relationship (r2 = 0.698). Bias analysis revealed a systematic underestimation of liver blood flow by TEE, possibly due to use of 0.57 as correction factor for mean velocity, while changes in liver blood flow were reliably detected.

CONCLUSION

TEE offers a noninvasive approach for monitoring hepatic perfusion and may be used in patients.

Electrocardiographic exercise stress testing for cardiac risk assessment in patients undergoing noncardiac surgery

BACKGROUND

The value of exercise electrocardiography in the prediction of perioperative cardiac risk has yet to be defined. This study was performed to determine the predictive value of exercise electrocardiography as compared with clinical parameters and resting electrocardiography.

METHODS

A total of 204 patients at intermediate risk for cardiac complications prospectively underwent exercise electrocardiography before noncardiac surgery. Of these, 185 were included in the final evaluation. All patients underwent follow-up evaluation postoperatively by Holter monitoring for 2 days, daily 12-lead electrocardiogram, and creatine kinase, creatine kinase MB, and troponin-T measurements for 5 days. Cardiac events were defined as cardiac death, myocardial infarction, minor myocardial cell injury, unstable angina pectoris, congestive heart failure, and ventricular tachyarrhythmia. Potential risk factors for an adverse event were identified by univariate and multivariate logistic regression analysis.

RESULTS

Perioperative cardiac events were observed in 16 patients. There were 6 cases of myocardial infarction and 10 cases of myocardial cell injury. The multivariate correlates of adverse cardiac events were definite coronary artery disease (odds ratio, 8.8; 95% confidence interval [CI], 1.1--73.1; P = 0.04), major surgery (odds ratio, 4.7; 95% CI, 1.3--16.3; P = 0.02), reduced left ventricular performance (odds ratio, 2.0; 95% CI, 1.1--3.8; P = 0.03), and ST-segment depression of 0.1 mV or more in the exercise electrocardiogram (odds ratio, 5.2; 95% CI, 1.5--18.5; P = 0.01). A combination of clinical variables and exercise electrocardiography improved preoperative risk stratification.

CONCLUSIONS

This prospective study shows that a ST-segment depression of 0.1 mV or more in the exercise electrocardiogram is an independent predictor of perioperative cardiac complications.

[Importance of acute PTCA in the treatment of perioperative myocardial infarction]

The mortality of perioperative myocardial infarction is still high and according to recently published data amounts to 17 to 42%. In the seventies introduction of thrombolytic therapy has led to a dramatic reduction in mortality of non-perioperative myocardial infarction. However, in the perioperative situation thrombolytic therapy remains to be problematic in most cases because of expected severe bleeding complications. In the last 4-6 years acute-PTCA has been established in the therapy of acute myocardial infarction. Up to date no data are available concerning the effect of acute-PTCA on mortality of perioperative myocardial infarction. Nevertheless it can be assumed, that acute-PTCA will lead to a considerable reduction in mortality of perioperative myocardial infarction. Therefore, in patients with significant perioperative myocardial infarction immediate coronary angiography and, if indicated, acute-PTCA should be performed. In principle, thrombolytic therapy is considered to be contraindicated in the intra- or postoperative situation. However, if coronary angiography and PTCA are not possible, thrombolysis might be taken into consideration, in particular if the expected bleeding complications are small in relation to the expected benefit of thrombolysis. Since acute-PTCA has been shown to remarkably reduce mortality in patients with cardiogenic shock after acute myocardial infarction, this group of patients should be especially considered.

[Acute myocardial infarction in patients with angiographically normal coronary arteries: clinical features and medium term follow-up]

BACKGROUND

Acute myocardial infarction (MI) in patients with normal coronary arteries has been recognized for several years. In most cases its etiology is unknown. The objective of the present study was to describe clinical features and medium term follow-up of those patients.

PATIENTS AND METHODS

Between April 1991 and December 1996, 9860 coronary angiographies were performed in our hospital. During this period 17 patients with documented myocardial infarction and completely normal coronary arteries were identified. Acute myocardial infarction was defined as the clinical event with acute angina pectoris, ST-elevation typical for myocardial infarction, and an increase in serum creatinine phosphokinase (CPK) above 125 U/l.

RESULTS

The mean peak CPK was 675 U/l (range: 129-1760 U/l). All 17 patients revealed significant ST-segment elevation. According to the ECG criteria there was no predilection for a specific location of MI (9 anterior MIs and 8 inferior MIs). Thrombolytic therapy was performed in 9 patients. In 12 patients areas of localized hypo- or akinesia were shown on left ventricular cineangiography. The mean ejection fraction was 61.5+/-10.3%. The age and sex distribution revealed a bimodel character: there was a younger age group of 9 patients, all men with a mean age of 35.9 years (31-43) and all strong cigarette smokers (mean 28 cigarettes/day) and there was an older group of 7 patients (1 man, 6 women) with a mean age of 56,4 years (47-68) and no significant association with cigarette smoking. During a mean follow-up period of 48.6 months (31-85 months) no patient died and no patient suffered from recurrent chest pain and used nitroglycerin occasionally.

CONCLUSION

Patients with acute MI and angiographically normal coronary arteries show a bimodal sex and age distribution: a younger age group, all men and uniformly strong cigarette smokers and an older group predominantly women with no significant association with cigarette smoking. Both groups seem to have a favorable prognosis.

Resolution of ST-segment elevation in acute myocardial infarction--early prognostic significance after thrombolytic therapy. Results from the COBALT trial

In acute myocardial infarction, early identification of patients at a high mortality risk is important for planning further therapeutic strategies. Previous studies have demonstrated that the extent of early resolution of ST-segment elevation may represent a simple, quick and noninvasive assessment to identify high risk groups of patients. In a subgroup of the COBALT Study population (Continuous Infusion vs Double Bolus Administration of Alteplase), ST-segment elevation was measured before and 90 to 120 minutes after treatment with alteplase. The subgroup of n = 1,760 patients was not different from the total COBALT population of n = 7169 patients regarding most clinical parameters except Killip Class before treatment. However, the overall 30-day mortality differed significantly between the main study and the substudy (7.76% vs 3.52%; p < 0.001). Three groups of ST-segment resolution were defined: 1. complete resolution (resolution > or = 70%; 762 patients), 2. partial resolution (< 70% and > 30%; 491 patients), 3. no resolution (< 30%; 507 patients). Mortality rate at 30 days for complete, partial and no resolution of ST-segment elevation was 1.31%, 4.28% and 6.11%, respectively (p < 0.001). While this significant correlation between the extent of ST-segment resolution and mortality could be observed for inferior acute myocardial infarction, it could not be found in patients with anterior acute myocardial infarction. This in part may be due to a selection bias that leads to an extremely divergent mortality rate of anterior acute myocardial infarction in the main study and the substudy (10.1% vs 3.94%; p < 0.0001). Despite this limitation, resolution of ST-segment elevation in acute myocardial infarction after thrombolytic therapy allows to identify patients at a high mortality risk and may help to select patients for early invasive procedures such as PTCA. Patients with complete ST-segment resolution showed a particularly low mortality rate, irrespective of the alteplase regimen used (front-loaded alteplase vs double bolus alteplase).

Perioperative transcutaneous pacemaker in patients with chronic bifascicular block or left bundle branch block and additional first-degree atrioventricular block

BACKGROUND

Complete heart block is dreaded perioperatively in patients with chronic bifascicular or left bundle branch block (LBBB) and additional first-degree A-V block. Our aim was to investigate the necessity as well as the efficacy and safety of transcutaneous pacing in the perioperative setting.

METHODS

Thirty-nine consecutive patients with asymptomatic chronic bifascicular block or LBBB and prolongation of the P-R interval scheduled to undergo surgery under anesthesia were prospectively enrolled in the study. Preoperatively, a transcutaneous pacemaker (PACE 500 D, Osypka Co.) was applied; its efficacy was checked with intra-arterial blood pressure measurement; the pain level was recorded. Additionally, 24-h Holter monitoring (CM2, CM5) was applied. Occurrences of a block progression or a bradycardia of <40 beats/min with hemodynamic impairment were the defined end points.

RESULTS

Thirty-seven of the 39 patients (95%) could be successfully stimulated with a median current strength of 70 mA; whereby 33 of the 39 patients felt moderate to severe pain. There was no perioperative block progression. Three cases of brady-cardia of <40 beats/min with a critical drop in blood pressure occurred; but these patients were successfully treated with drug therapy without pacemaker stimulation.

CONCLUSION

The perioperative application and testing of the pacemaker was safe and could be performed in nearly all patients successfully. However, we do not consider a routine prophylactic transcutaneous placement in patients with chronic bifascicular or LBBB and additional first-degree A-V block justified. Nevertheless, appropriate drugs and temporary pacemaker equipment should be easily accessible.

Effect of reteplase on hemostasis variables: analysis of fibrin specificity, relation to bleeding complications and coronary patency

The first aim of the present study was to characterize the systemic and fibrin-specific lytic effect of reteplase in the treatment of patients with acute myocardial infarction. The second aim was to investigate the relation of hemostasis variables to risk of bleeding complications and to coronary patency. The present study is a hemostatic substudy of the German Recombinant Activator Study. Forty two patients have been treated with 10 MU of reteplase (Group A) and 100 patients with 15 MU of reteplase (Group B), given as a single bolus. Blood samples for assessment of fibrinogen, plasminogen, alpha-2-antiplasmin, fibrinogen degradation products (FDP) and D-dimers were obtained before and at 2, 4, 8, and 24 h after thrombolytic therapy. The median fibrinogen concentration was decreased from 279 to 169 mg/dl in Group A and from 254 to 92 mg/dl in Group B four hours after administration of reteplase. The decrease in fibrinogen was significantly more pronounced in Group B (P=0.0004). The median plasminogen concentration was decreased to 53% in Group A and to 33% in Group B two hours after administration of reteplase (P=0.0001). Alpha-2-antiplasmin was reduced to 27% and 17,5%, respectively (P=0.0007). D-Dimer levels were increased to 5.2 microg/ml in Group A and 11,6 microg/ml in Group B (P=0.02) and FDP levels to 3.0 microg/ml in Group A and 12,6 microg/ml in Group B (P=0.04). Patients with bleeding complications revealed significant lower nadir levels of fibrinogen than patients without bleeding complications (54 mg/dl versus 125.5 mg/dl, P=0.02). There was no significant difference in any hemostatic parameter between patients with patent and nonpatent infarct related arteries.

CONCLUSIONS

Reteplase causes a moderate systemic lytic effect comparable with other relative fibrin specific thrombolytic agents. An increase in the dose from 10 to 15 MU is associated with a marked increase in both fibrin specific and systemic lytic effect. Patients with bleeding complications reveal significant lower nadir levels of fibrinogen than patients without bleeding complications. Determination of any hemostatic parameter seems to be no useful method to predict efficacy of thrombolysis in terms of coronary patency in the individual patient.

Influence of amiodarone on QT dispersion in patients with life-threatening ventricular arrhythmias and clinical outcome

Increased QT dispersion, defined as the difference between the maximum and minimum QT interval on the standard 12-lead electrocardiogram is assumed to reflect regional inhomogeneity of ventricular repolarization and has been shown to be associated with an increased risk of arrhythmic events. The purpose of the present study is to examine the influence of amiodarone on QT dispersion in patients with life-threatening ventricular arrhythmias and to evaluate the predictive value of QT dispersion after amiodarone therapy for further arrhythmic events. ECG's were obtained in 47 patients 1-2 days before and 6-8 weeks after amiodarone was started. All patients had coronary artery disease with a mean EF of 34 +/- 14%. The QT interval was measured in each lead of a digitized ECG displayed on a high resolution monitor (250 mm s-1). Amiodarone therapy resulted in a significant increase in the maximal QTc interval (476 +/- 44 to 505 +/- 44 ms, p < 0.001). However, measurement of QT dispersion (70 +/- 34 vs 73 +/- 29 ms) and Qtc dispersion (78 +/- 37 vs 77 +/- 31 ms) revealed no significant difference before and after amiodarone. During a one year follow-up period 26 patients were free of arrhythmic events and 7 patients developed further arrhythmic events. The remaining 14 patients were excluded from the one year follow-up analysis because of drug discontinuation (n = 8), death due to heart failure (n = 1), medical intervention (n = 3) and incomplete follow-up (n = 2). No measure of QT dispersion was predictive of recurrent arrhythmic events during treatment with amiodarone.

CONCLUSION

Treatment with amiodarone results in significant QT prolongation without altering QT dispersion. Measurements of QT dispersion were not predictive of amiodarone efficacy in this patient population.

The effect of erythropoietin on lactate, pyruvate and excess lactate under physical exercise in dialysis patients

To investigate EPO-induced increase of hemoglobin on energy metabolism plasma concentrations of lactate (L), pyruvate (P) and excess lactate (XL) were determined in ten dialysis patients at rest, immediately after 6 minutes of ergometric exercise as well as after recovery for 15 and 30 min. The investigations were performed before EPO-therapy at a mean Hb = 7.5 +/- 0.9 g/dl and under EPO-therapy at a mean Hb = 10.0 +/- 0.6 g/dl and at a mean Hb = 11.9 +/- 0.8 g/dl. Ten healthy subjects were subjected to the same investigation at Hb = 14.7 +/- 1.1 g/dl. There was a significant rise of L and XL in all patient groups under ergometric exercise. The increase of hemoglobin from 7.5 g/dl to 10.0 g/dl led to significantly (p < 0.01) lower L and XL concentrations immediately after exercise (L = 4.62 vs 3.23 mmol/l, XL = 2.37 vs 1.38 mmol/l). The further decrease of the mean L and XL values (L = 2.88 mmol/l, XL = 1.05 mmol/l) associated with the rise of hemoglobin to 11.9 g/dl could not be confirmed statistically. In contrast to all patient groups, there was no significant rise in XL in the healthy control subjects under physical exercise. The present results make it evident that patients with renal anemia react even to light physical exercise with pronounced tissue hypoxia in contrast to healthy subjects. The increase of the hemoglobin content under the EPO-therapy leads to a marked reduction of the tissue hypoxia and consequently of anaerobic energy production. A further rise of the hemoglobin content above and beyond 10.5 g/dl will have an additional positive effect on oxygen supply only in occasional cases. The comparison with healthy subjects shows that despite a very large degree of normalization of the hemoglobin content, no normalization of energy metabolism can be attained.