Heinz Weber

Evaluation of esophageal tracheal combitube in cardiopulmonary resuscitation.

Prompt establishment of an airway is a primary goal in CPR of nonbreathing and unconscious patients. The esophageal tracheal combitube (ETC) is a new airway, designed for emergency intubation providing sufficient ventilation whether the airway is placed into the trachea or into the esophagus. We evaluated the effectiveness of the ETC in 31 patients during CPR. Blood gas analyses obtained during esophageal placement of the ETC showed results comparable to those of ventilation with a conventional endotracheal airway (ETA). The ETC appeared to oxygenate and ventilate patients adequately without complications. The efficacy, safety, and ease of insertion ensure rapid airway control. It is concluded that the ETC provides a sufficient alternative to the ETA whenever ideal conditions or trained staff for endotracheal intubation are not immediately available.

Prognostic value of heart rate variability in patients awaiting cardiac transplantation.

Time and frequency domain parameters of heart rate variability (HRV) were determined in patients with severe end stage heart failure awaiting cardiac transplantation (HTX). These parameters were then correlated with mortality to investigate the performance of HRV in discriminating between groups with high and low risk of death. The standard deviation of five consecutive RR intervals (SDANN) was found to be the parameter with the greatest sensitivity (90%) and specificity (91%). Patients with SDANN values of < 55 msec had a twenty‐fold increased risk of death (90% confidence limits: 4–118, P < 0.001). The results furthermore suggest that measurements of HRV are superior to other prognostic markers such as left ventricular ejection fraction, pulmonary artery wedge pressure, cardiac index, and serum sodium levels. We conclude that HRV is a powerful, noninvasive tool to assess the risk of death in candidates for HTX. HRV measurements can therefore be used as a supplement to other markers of risk to determine the optimal therapeutic strategy in patients with severe congestive heart failure.

Diurnal variation of ventricular response to atrial fibrillation in patients with advanced heart failure

Variability of ventricular rate was quantified by two measures of heart rate variability: the SD of the mean R-R interval (SDNN) and the SD of the 5-minute mean R-R interval (SDANN). In 35 patients with atrial fibrillation and advanced heart failure (left ventricular ejection fraction 20% +/- 9%, cardiac index 2.4 +/- 0.7 L/min/m2), SDNN and SDANN were compared to 13 preselected clinical and hemodynamic variables for prediction of outcome. During a 12-month follow-up period, 8 (23%) patients deteriorated clinically; 3 (9%) died, and 5 (14%) underwent heart transplantation. SDNN and SDANN correlated to the difference of the mean R-R interval between night (2 AM to 3 PM) and day (11 AM to noon) with r values of 0.62 and 0.77, respectively. From 15 preselected variables, only SDANN (chi 2 = 6.7, p = 0.01) was independently associated with survival on multivariate analysis. Dichotomized SDANN at 100 msec accurately predicted 12-month survival in 28 (80%) patients (relative risk = 9.77, p = 0.001). In conclusion, analysis of heart rate variability is useful in quantifying diurnal variation of ventricular rate in atrial fibrillation and might be useful in predicting survival in patients with advanced heart failure.

Noninvasive estimation of coronary flow reserve by transesophageal Doppler measurement of coronary sinus flow

Abstract Currently available methods for the measurement of coronary flow reserve (CFR) are invasive and time-consuming, and need adequate laboratory equipment and staff. 1–4 Furthermore, most of these methods are limited by various methodologic problems. 5,6 Transesophageal echocardiography enables visualization of the distal coronary sinus in most patients. Accordingly, we investigated the ability of transesophageal echocardiography to calculate CFR by Doppler measurement of coronary sinus flow (CSF) at rest and after dipyridamole administration.

Beneficial hemodynamic effects of prostaglandin E1 infusion in catecholamine-dependent heart failure: results of a prospective, randomized, controlled study.

ObjectiveTo study the hemodynamic effects of prostaglandin E1: (PGE1)administered in addition to a standard catecholamine infusion in patients with severe chronic heart failure. DesignProspective, placebo-controlled, randomized, single-blind study. SettingIntensive care unit at a university hospital. PatientsThirty patients with severe chronic heart failure, New York Heart Association functional class TV (28 men, two women, with a mean age of 54 ± 2 yrs, mean left ventricular ejection fraction 10 ± 0.6%). All patients received oral therapy with digitalis, furosemide (mean dose 300 ± 46 mg/day), and enalapril (20 ± 2.7 mg/day). InterventionsHemodynamic measurements using pulmonary artery flotation catheters were performed at baseline, ≥24 hrs after standardized catecholamine infusion with dopamine (3 μg/kg/min) and dobutamine (5 μg/kg/min), as well as 48 hrs after randomization to infusion therapy with PGE1 (30 μg/kg/min) or a placebo. Measurements and Main ResultsThe addition of PGE1 to an ongoing catecholamine infusion in 20 patients caused a 16 ± 4% decrease in mean pulmonary arterial pressure (p < .001), a 22 ± 5% decrease in pulmonary artery occlusion pressure (p < .0001), a 24 ± 8% decrease in pulmonary vascular resistance index (p < .001), a 20 ± 9% decrease in right atrial pressure (p < .01), a 14 ± 3% decrease in mean arterial pressure (p < .001), and a 29 ± 4% decrease in systemic vascular resistance index (p < .0001). These PGE1- induced decreases occurred without a change in heart rate.Stroke volume index increased with PGE1 therapy by 34 ± 7% (p < .0001), and cardiac index increased by 34 ± 6% (p < .0001). No hemodynamic changes were observed during combined infusion with catecholamines and placebo in ten patients. ConclusionPGE1 improves the hemodynamic state in end-stage chronic heart failure patients already receiving a standard dose dopamine/ dobutamine infusion. (Crit Care Med 1994; 22:1084–1090)

Infusion of nifedipine after coronary artery bypass grafting decreases the incidence of early postoperative myocardial ischemia

We performed a randomized study on patients undergoing elective coronary bypass grafting to examine whether postoperative infusion of nifedipine (n = 25) could reduce the incidence of isolated transient myocardial ischemia, myocardial infarction, or both. The control group (n = 25) received nitroglycerin. Hemodynamic and Holter monitoring and serial assessment of enzymatic and electrocardiographic changes were performed for all patients. Both groups showed comparable preoperative and operative data. The incidence of myocardial infarction was significantly lower in the nifedipine group (n = 1) as compared with the control group (n = 4), whereas the number of patients with isolated transient myocardial ischemia was similar in both groups (nifedipine, 3; control, 4). At the time of peak activity, levels of creatine kinase (350 +/- 129 versus 511 +/- 287 IU/mL), creatine kinase-MB (8.4 +/- 5.4 versus 17.1 +/- 11.0 IU/mL), and glutamate-oxaloacetate-transaminase (30.4 +/- 4.4 versus 41.0 +/- 7.9 IU/mL) were markedly lower in the nifedipine group (p less than 0.05). We conclude that infusion of nifedipine after elective coronary artery bypass grafting effectively decreases the incidence of myocardial infarction and the extent of myocardial necrosis during the early postoperative period.

Stress-induced cardiomyopathy (Tako-Tsubo syndrome) in Austria

Background: Tako-Tsubo syndrome (TS) is a still rarely diagnosed clinical syndrome, which is characterized by acute onset of chest pain, transient cardiac dysfunction with (frequently) reversible wall motion abnormalities (WMAs), but with no relevant obstructive coronary artery disease. Methods and results: Among 179 consecutive patients with proven diagnosis of TS that were retrospectively analysed in this multicentre registry, women represented the majority of patients (94%) while only 11 men (6%) developed TS. Mean age was 69.1±11.5 years (range 35–88 years). Cardinal symptoms of TS, which led to admission, were acute chest pain (82%) and dyspnoea (32%), respectively. All patients demonstrated typical WMAs, whereby four different types of WMAs could be defined: (1) a more common apical type of TS (n=89; 50%); (2) a combined apical and midventricular form of TS (n=23; 13%); (3) the midventricular TS (n=6; 3%); and (4) an unusual type of basal WMAs of the left ventricle (n=3). Only in 101 patients (57%), a clear causative trigger for onset of symptoms could be identified. In-hospital cardiovascular complications occurred in 25 patients (14%) and consisted of cardiac arrhythmias in 10 patients (40%), cardiogenic shock in six patients (24%), cardiac decompensation in eight patients (32%) and cardiovascular death in one patient, respectively. Echocardiographic control of left ventricular function after the initial measurement was available in almost 70% of the patients: complete recovery of WMAs was found in 73 patients (58.87%); 49 patients (39.52%) showed persistent WMAs. Recurrences of TS were only seen in four patients. During the follow-up period, 13 patients died: three of cardiovascular causes and 10 of non-cardiac causes. In-hospital mortality was 0.6%, 30-day mortality was 1.3% and 2-year mortality was 6.7%. Conclusions: This study represents to date the largest series of patients suffering from TS in Austria and worldwide. Similar to others, in our series the prevalence of TS was significantly higher in women than in men, while in contrast to other studies, the apical type of TS was detected most frequently. The similar clinical presentation of TS patients to the clinical picture of acute myocardial infarction demonstrates the importance of immediate coronary angiography for adequate differential diagnosis of TS. TS is not necessarily a benign disease due to cardiovascular complications as well as persistent WMAs with delayed recovery.

Increased heart rate variability after radiofrequency ablation.

Abstract Radiofrequency ablation is a safe and highly effective modality of treatment for patients with atrioventricular (AV) nodal reentrant 1 and circus movement 2,3 tachycardias. Inappropriate sinus tachycardia has been described after the procedure. 4 Vagal withdrawal has been implicated in its occurrence, assuming damage of postganglionic parasympathetic fibers in the region of the AV node. 4 In the present study, heart rate (HR) variability was analyzed after radiofrequency ablation to further characterize any direct or indirect effect of radiofrequency energy on the sinus node.

Subsidiary pacemaker function in complete heart block after His-bundle ablation.

To investigate the electrophysiological properties of ventricular impulse formation after His-bundle ablation in 11 patients, incremental ventricular overdrive stimulation studies were performed. The studies, which were spread over a follow-up period of up to 601 days, were carried out invasively with temporary leads as well as noninvasively with the implanted pacemakers and chest wall inhibition. The overdrive pacing rate was increased in steps of 10 beats/min, and the pacing duration was 2 minutes at each level. Ten out of 11 patients had a reliable ventricular escape rhythm; in the remaining patient, consistently no subsidiary pacemaker function was observed up to 10 seconds. In 83% of the studies, incremental ventricular overdrive stimulation caused progressive suppression of ventricular impulse formation with exponential increase in ventricular recovery time and progressive postrecovery subsidiary pacemaker depression. In the remaining 17%, ventricular recovery time showed a heterogeneous response to overdrive stimulation--as possible cause alterations in the sympathetic tone and limitations attributable to the method used are discussed. The results of this study demonstrate a rate-dependent overdrive suppression of subsidiary ventricular pacemaker tissue. This can be of clinical importance in patients with complete heart block and rate-adaptive pacemakers because sudden pacemaker failure or temporary pacemaker inhibition at high stimulation rates may cause Stokes-Adams attacks not reproducible at lower pacing rates.

Potential life-threatening cardiac arrhythmias associated with a conventional hypocaloric diet

Nine obese children (mean age 12.7 years, mean overweight 74.2%) were treated for 3 weeks with a very low calorie diet containing high quality protein. Eight patients (patients A) received a commercially available diet (240 kcal/1004 kJ/day) and 1 patient (patient B) a homemade dietary regimen (500 kcal/2100 kJ/day). Both preparations were supplemented with micronutrients; however, the daily intake of minerals was significantly less in patient B. All patients were monitored for the appearance of cardiac arrhythmias by frequent 24-hour Holter recordings. In patients A the mean loss of body weight was 9.4 +/- 2.4 kg, patient B lost 8.7 kg. The mean daily nitrogen balance was negative (patients A: 10.2 g/day, patient B: 6.8 g/day). Frequent blood chemistry evaluations were unremarkable. On the 14th day of treatment patient B developed arrhythmias (ventricular couplets, non-sustained ventricular tachycardias); in patients A no ventricular dysrhythmias were observed. Our data suggest that very low calorie diets containing protein of high biologic value can be associated with potentially dangerous arrhythmias.