Direct comparison of the diagnostic performance of growth differentiation factor 8 in pediatric versus adult heart failure

INTRODUCTION

Growth differentiation factor 8 (GDF-8, myostatin) has been proposed for the management of adult heart failure (HF). Its potential role in pediatric HF patients is unknown. We sought to investigate its diagnostic performance in adult versus pediatric HF.

METHODS

GDF-8 was measured prospectively in pediatric and adult HF patients and in matching controls. HF was defined as the combination of typical symptoms and impaired left ventricular systolic function. Diagnostic performance for the detection of HF was evaluated by receiver operating characteristic (ROC) analysis.

RESULTS

We enrolled 137 patients with HF (85 pediatric) and 67 healthy controls (47 pediatric). Neither pediatric nor adult HF patients had significantly different GDF-8 levels compared to the reference groups (3.53 vs 3.46 ng/mL, p = 0.334, and 6.87 vs 8.15 ng/mL, p = 0.063, respectively), but pediatric HF patients had significantly lower GDF-8 levels compared to adult patients (p < 0.001). ROC analysis showed no significant improvement adding GDF-8 to NT-proBNP, age and sex (area under the curve (AUC): 0.870 vs 0.868, p = 0.614) in children and neither in addition to age nor sex in adult HF patients (AUC: 0.74 vs 0.62, p = 0.110).

CONCLUSION

GDF-8 did not accurately differentiate between HF patients and normal comparators in neither adults nor in children.

ECG Smart Monitoring versus Implantable Loop Recorders for Atrial Fibrillation Detection after Cryptogenic Stroke-An Overview for Decision Making

Up to 20% of patients with ischemic stroke or transient ischemic attack have a prior history of known atrial fibrillation (AF). Additionally, unknown AF can be detected by different monitoring strategies in up to 23% of patients with cryptogenic or non-cardioembolic stroke. However, most studies had substantial gaps in monitoring time, especially early after the index event. Following this, AF rates would be higher if patients underwent continuous monitoring early after stroke, avoiding any gaps in monitoring. The few existing randomized studies focused on patients with cryptogenic stroke but did not focus otherwise specifically on prevention strategies in patients at high risk for AF (patients at higher age or with high CHA2DS2-VASC scores). Besides invasive implantable loop recorders (ILRs), external loop recorders (ELRs) and mobile cardiac outpatient telemetry (MCOT) are non-invasive tools that are commonly used for long-term ECG monitoring in cryptogenic-stroke patients in the ambulatory setting. The role of MCOT and hand-held devices within ECG smart monitoring in the detection of AF for the prevention of and after cryptogenic stroke is currently unclear. This intense review provides an overview of current evidence, techniques, and gaps in knowledge and aims to advise which patients benefit most from the current available devices.

Gapless Electrocardiogram-Monitoring in stroke at high risk of atrial fibrillation

BACKGROUND AND PURPOSE

Previous studies investigating prolonged electrocardiogram (ECG)-monitoring after ischemic stroke had significant gaps between the index event and the beginning of long-term monitoring. Atrial fibrillation (AF) detection might be higher if prolonged cardiac rhythm documentation is performed with a gapless approach without any interruption of monitoring time.

METHODS

This investigator-initiated, prospective study included patients with acute ischemic stroke or transient ischemic attack at three study centers. Participants received gapless ECG-monitoring via telemetry during stroke-unit admission until implantation of an insertable cardiac monitor (ICM) within the first days after the index event. Patients acted as their own controls and also received standard 24-72-h Holter ECG.

RESULTS

A total of 110 patients were included, of whom 86 (78.2%) had an embolic stroke of unknown source, 14 (12.7%) had small-vessel disease, and 10 (9.1%) had large-artery disease. AF was newly diagnosed in 17 (15.5%) patients via ICM monitoring, compared to one (0.9%) patient via Holter ECG during 6 months of follow-up (p < 0.001). The detection rate of AF within the first 30 days was 10.0%, which accounted for 64% of all new AF diagnoses. The median duration of the detected episodes was 1.7 (interquartile range = 0.2-4.7) h. All patients with new onset AF were treated with oral anticoagulation.

CONCLUSIONS

Gapless ECG-monitoring is an effective strategy to significantly increase the detection rate of AF after ischemic stroke. This finding supports the use of long-term ECG-monitoring with a gapless approach without any interruption in monitoring time as the gold standard for clinical practice.

ST-T segment changes in prehospital emergency physicians in the field: a prospective observational trial

Aims

Due to time-critical decision-making, physical strain and the uncontrolled environment, prehospital emergency management is frequently associated with high levels of stress in medical personnel. Stress has been known to cause ischemia like changes in electrocardiograms (ECGs), including arrhythmias and deviations in ST-T segments. There is a lack of knowledge regarding the occurrence of changes in ST-T segments in prehospital emergency physicians. We hypothesized that ST-T segment deviations occur in prehospital emergency physicians in the field.

Methods

In this prospective observational trial, ST-T segments of emergency physicians were recorded using 12-lead Holter ECGs. The primary outcome parameter was defined as the incidence of ST-T segment changes greater than 0.1 mV in two corresponding leads for more than 30 s per 100 rescue missions. The secondary outcomes included T-wave inversions and ST-segment changes shorter than 30 s or smaller than 0.1 mV. Surrogate parameters of stress were measured using the NASA-Task Load Index and cognitive appraisal, and their correlation with ST-T segment changes were also assessed.

Results

Data from 20 physicians in 36 shifts (18 days, 18 nights) including 208 missions were analysed. Seventy percent of previously healthy emergency physicians had at least one ECG abnormality; the mean duration of these changes was 30 s. Significantly more missions with ECG changes were found during night than day shifts (39 vs. 17%, p < 0.001). Forty-nine ECG changes occurred between missions. No ST-T segment changes > 30 s and > 0.1 mV were found. Two ST-T segment changes < 30 s or < 0.1 mV (each during missions) and 122 episodes of T-wave inversions (74 during missions) were identified. ECG changes were found to be associated with alarms when asleep and NASA task load index.

Conclusion

ECG changes are frequent and occur in most healthy prehospital emergency physicians. Even when occurring for less than 30 s, such changes are important signs for high levels of stress. The long-term impact of these changes needs further investigation.

Trial registration The trial was registered at ClinicalTrials.gov (NCT04003883) on 1.7.2019: https://clinicaltrials.gov/ct2/show/NCT04003883?term=emergency+physician&rank=2

New Generation Miniaturized Insertable Cardiac Monitor with a Long Sensing Vector: Insertion Procedure, Sensing Performance, and Home Monitoring Transmission Success in a Real-World Population

Background

Objective

Methods

Results

Conclusion

Clinical outcomes of pacemaker implantations before and after cancer diagnosis

Background

Cardiotoxicity caused by anticancer treatment affects cardiac conduction. Clinical outcomes of pacemaker patients with newly diagnosed cancer are insufficiently understood.

Purpose

The aim was to investigate the effect of anticancer therapy on pacemaker properties.

Methods

All patients with pacemaker and confirmed cancer diagnosis treated with chemotherapy at our tertiary university hospital were included in this study. The pacemaker database (containing pacemaker related information) was matched with hospital-wide electronic health records (containing cancer types, comorbidities and echo data). Survival data were retrieved from the Statistics Austria Federal Institute. Clinical and pacemaker data of patients with previously diagnosed cancer requiring pacemaker implantation (Group A) were compared to patients with pre-existing pacemaker followed by cancer diagnosis (Group B).

Results

Out of 972 included patients, 295 patients (30.3%) had the pacemaker implantation after their first cancer diagnosis (Group A), and 677 patients (69.7%) had already a pacemaker before their first cancer diagnosis (Group B). Cancer types are displayed in Figure 1. The following cancer types were associated with increased likelihood for pacemaker implantation after cancer diagnosis (Group A): kidney cancer (OR 2.07, 95% CI 1.12 to 3.83, P=0.02), lymphomas (OR 2.27, 95% CI 1.21 to 4.26, P=0.01), and eye cancer (OR 9.29, 95% CI 1.03 to 83.50, P=0.047). Patients in Group A were older at pacemaker implantation (76.0 years [IQR 68.0–82.2] vs. 72.1 years [IQR 64.3–78.0], P&lt;0.001), and single-chamber pacemakers were less frequent (21.8% vs. 32.1%, P=0.001). Pacemaker implantation due to bradycardic atrial fibrillation was less frequent in Group A (15.6% vs. 21.8%, P=0.03), but implantation due to an “unspecified” indication was increased (20.6% vs. 12.7%, P=0.002). Patients in Group A had lower pacing threshold at baseline but had a stronger increase in pacing threshold during the follow-up as indicated in Table 1. No differences regarding left or right ventricular function, left or right end-diastolic diameter, or mitral or tricuspid regurgitation were detected between the groups. Patients in Group A had smaller left atria (59.7±10.7mm vs. 63.9±24.0mm, P=0.02) and smaller right atria (57.9±10.4mm vs. 61.2±11.8mm, P=0.001). Patients with cancer diagnosis requiring pacemaker had worse 10-year survival (31.2% vs. 51.1%, log-rank P&lt;0.001) as shown in Figure 1.

Conclusion

Kidney cancer, lymphoma, and cancer of the eye were associated with increased probability of pacemaker implantation after cancer diagnosis. The significant increase in pacing threshold in patients undergoing chemotherapy could be associated with chemotherapy-induced cardiotoxicity.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Union's Horizon 2020 Future and Emerging Technologies Programme Figure 1. Cancer types and survivalTable 1. Baseline characteristics

Cardiac biomarkers for risk stratification of arrhythmic death in patients with heart failure and reduced ejection fraction

Objectives. Patients with heart failure and reduced left ventricular ejection fraction (HFrEF) are prone to ventricular tachyarrhythmias. We tested whether biomarkers C-terminal Endothelin 1 (CT-ET1), midregional pro atrial natriuretic peptide (MR-proANP) and midregional pro adrenomedullin (MR-proADM) might improve risk stratification for arrhythmic death.Methods: This prospective observational study included 160 heart failure patients with ischaemic cardiomyopathy (ICM) or non-ischaemic, dilated cardiomyopathy (DCM) and 30 control patients without heart disease. Primary endpoint was arrhythmic death (ArD) or resuscitated cardiac arrest (resCA).Results: A total of 61 patients died during the median follow-up of 7.0 [5.2-8.4] years. An ArD or resCA was observed in 48 patients. Plasma levels of CT-ET1 (p = 0.002), MR-proANP (p < 0.001) and MR-proADM (p = 0.013) were significantly higher in ICM or DCM patients compared to controls. MR-proANP levels in ICM patients were associated with a significantly increased risk for ArD or resCA (hazard ratio (HR) = 1.42, [95%CI: 1.08-1.85], p = 0.011) in a multivariable Cox regression model. Plasma levels of CT-ET1 (HR = 1.07 [0.98-1.17], p = 0.113) and MR-proADM (HR = 1.80 [0.92-3.55], p = 0.087) were not associated with ArD or resCA in ICM patients. No significant association with ArD or resCA was found in DCM patients. Multivariable Cox regression showed that CT-ET1 (HR = 1.14 [1.07-1.22], p < 0.001), MR-proANP (HR = 1.64 [1.29-2.08], p < 0.001) and MR-pro ADM (HR = 2.06 [1.12-3.77], p = 0.020) were associated with a higher risk for overall mortality.Conclusion: Patients with HFrEF had elevated levels of CT-ET1, MR-proANP and MR-proADM. Plasma levels of MR-proANP are useful as predictor for arrhythmic death in patients with ICM.

Pacemaker lead-associated tricuspid regurgitation in patients with or without pre-existing right ventricular dilatation

Background

Transcatheter tricuspid valve intervention became an option for pacemaker lead-associated tricuspid regurgitation. This study investigated the progression of tricuspid regurgitation (TR) in patients with or without pre-existing right ventricular dilatation (RVD) undergoing pacemaker implantation.

Methods

Patients were included if they had implantation of transtricuspid pacemaker lead and completed echocardiography before and after implantation. The cohort was divided in patients with and without RVD (cut-off basal RV diameter ≥ 42 mm). TR was graded in none/mild, moderate, and severe. Worsening of one grade was defined as progression. Survival analyses were plotted for 10 years.

Results

In total, 990 patients were analyzed (24.5% with RVD). Progression of TR occurred in 46.1% of patients with RVD and in 25.6% of patients without RVD (P < 0.001). Predictors for TR progression were RV dilatation (OR 2.04; 95% CI 1.27–3.29; P = 0.003), pre-existing TR (OR 4.30; 95% CI 2.51–7.38; P < 0.001), female sex (OR 1.68; 95% CI 1.16–2.43; P = 0.006), single RV lead (OR 1.67; 95% CI 1.09–2.56; P = 0.018), mitral regurgitation (OR 2.08; 95% CI 1.42–3.05; P < 0.001), and enlarged left atrium (OR 1.98; 95% CI 1.07–3.67; P = 0.03). Survival-predictors were pacemaker lead-associated TR (HR 1.38; 95% CI 1.04–1.84; P = 0.028), mitral regurgitation (HR 1.34; 95% CI 1.02–1.77; P = 0.034), heart failure (HR 1.75; 95% CI 1.31–2.33; P < 0.001), kidney disease (HR 1.62; 95% CI 1.25–2.11; P < 0.001), and age ≥ 80 years (HR 2.84; 95% CI 2.17–3.71; P < 0.001).

Conclusions

Patients with RVD receiving pacemaker suffered from increased TR progression, leading to decreased survival.

Graphic abstract

Comparison of burst versus ramp antitachycardia pacing therapy for ventricular tachycardia: A meta-analysis

Current guidelines recommend at least one attempt of defibrillator antitachycardia pacing (ATP) therapy, showing preference for burst therapy. The objective of this study is to compare ramp versus burst ATP therapy proportion of success and acceleration in treating spontaneous or induced ventricular tachycardia (VT). The review protocol was previously published in PROSPERO. Data synthesis and measures of heterogeneity (I² ) was performed by CMA® software v.3 comparing proportions in both groups. Sensitivity analysis was performed as subgroup or meta-regression according to quality, clinical characteristics, and differences in design. Thirteen studies including 30,117 VT episodes in 1672 patients were analyzed. There was no significant difference in the proportion of success between burst and ramp therapy in spontaneous VT (odds ratio = 1.116; 95% confidence interval [CI] = 0.788-1.579; I²  = 89%). There was no significant difference in the proportion of success between burst and ramp therapy in induced VT (odds ratio = 0.820; 95% CI = 0.468-1.437; I²  = 93%). No significant difference was found in the proportion of acceleration between burst and ramp in spontaneous VT (odds ratio = 0.792; 95% CI = 0.476-1.317; I²  = 83%). No significant difference was found in the proportion of acceleration between burst and ramp in induced VT (odds ratio = 1.234; 95% CI = 0.802-1.898; I²  = 55%). Sensitivity analysis did not change main results. There is no difference in success or in acceleration proportion between burst or ramp ATP therapy irrespective if the VT was spontaneous or induced. Future implantable cardioverter defibrillator programming guidelines should offer both ATP therapies without preference in one of them.

Sex Differences and Long-Term Outcome in Patients With Pacemakers

Introduction: Evidence of sex-related differences in patients with pacemakers regarding comorbidities is insufficiently investigated. The aim of this study was to determine the relationship of cardiovascular comorbidities and sex category with properties of pacemaker implantation, pacemaker follow-up, and long-term survival.

Methods: This retrospective, single-center cohort study consisted of 6,362 pacemaker-patients (39.7% female) enrolled between May 2000 and April 2015. Functional pacemaker parameters were registered at regular pacemaker controls. Survival status and cause of death were analyzed in relation to comorbidities, implanted pacing devices, and echocardiography. Survival analyses were plotted for a 10-year follow-up.

Results: Patients with hypertension or hyperlipidemia had higher rates of implantations due to sick sinus syndrome (28.6 vs. 25.5% without hypertension, P < 0.001; 30.7 vs. 25.7% without hyperlipidemia, P < 0.001), while endocarditis was associated with higher rates of implantations due to AV block (46.7 vs. 33.4%, P < 0.001). Patients with valvular heart disease had higher rates of pacemaker implantation due to bradycardic atrial fibrillation (24.9 vs. 21.0% without valvular heart disease, P < 0.001). Ventricular pacing threshold increased in both sexes during the follow-up and was higher in women in the final follow-up (0.94 vs. 0.91 V in men, P = 0.002). During the 10-years follow-up, 6.1% of women and 8.6% of men underwent lead replacement (P = 0.054). Device and lead replacement rates were increased if the comorbidities coronary artery disease, heart failure, hypertension, hyperlipidemia, valvular heart disease, previous stroke/TIA, atrial arrhythmias, chronic kidney disease, or endocarditis were present. Diabetes and previous CABG increase the rates of device replacement, but not the rate of lead replacement. Severe tricuspid regurgitation after implantation of pacemaker was present in more men than women (14.4 vs. 6.1%, P < 0.001). In a multivariate COX regression, the following variables were associated with independent decrease of 10-year survival: hypertension (HR 1.34, 95% CI 1.09–1.64), chronic kidney disease (HR 1.83, 95% CI 1.53–2.19), tricuspid regurgitation after pacemaker implantation (HR 1.48, 95% CI 1.26–1.74). Survival was independently increased in female sex (HR 0.83, 95% CI 0.70–0.99) and hyperlipidemia (HR 0.81, 95% CI 0.67–0.97).

Conclusions: Cardiovascular comorbidities influenced significantly pacemaker implantations and long-term outcome.

Trial Registration:ClinicalTrials.gov Unique identifier: NCT03388281.

Pacemaker lead-induced progression of primary vs. secondary tricuspid regurgitation

Background

Currently no data are available whether the implantation of right ventricular (RV) pacemaker (PM) lead worsens preexisting primary or secondary (functional due to RV dilatation, RVD) tricuspid regurgitation (TR).

Purpose

The aim of the present retrospective analysis was to assess TR after PM implantation with a RV lead.

Methods

Patients with PM implantation (n=990) were enrolled if they had routine echocardiography including assessment of TR before first implantation and immediately after. RVD and severity of TR were characterized visually. Based on RVD in baseline echocardiography, patients were divided into 2 groups: with primary TR (without preexisting RVD, n=743) or secondary TR (with preexisting RVD, n=243).

Results

Lead-induced worsening of TR was present in both groups (Table 1). Progression from mild/moderate to severe TR was observed in 6.7% of patients with primary TR, compared to 25.6% of patients with secondary TR (P=0.001). Using an ordinal regression model, the probability to progress to severe TR with primary TR was 14.8% (95% CI 11.0%-19.7%), compared to 41.6% (95% CI 40.3%-42.8%) with secondary TR (P&lt;0.001).

Conclusion

Preexisting secondary TR was associated with higher rates of lead-induced progression to severe TR compared to primary TR. Leadless pacing or tricuspid valve clipping post-PM implantation could be an option for patients with preexisting secondary TR and indication for a PM.

Table 1. Patient characteristics.

Funding Acknowledgement

Type of funding source: Public grant(s) – EU funding. Main funding source(s): This study was supported by the European Union's Horizon 2020 Future and Emerging Technologies Programme [Grant number 732170].

Fitness to Drive After Syncope and/or in Cardiovascular Disease - An Overview and Practical Advice

The risk of syncope occurring while driving has implications for personal and public safety. Little is thought about the medical considerations related to the driving of motor vehicles. Physicians treating patients with cardiovascular disease need to acquire basic competences to be able to advise them about their fitness to drive. Current knowledge, governmental regulations, and recommendations concerning fitness to drive in patients with syncope and/or cardiovascular disease are presented. Narrative review with educational and clinical advice. Cardiovascular disease can make a driver lose control of a vehicle without warning and thereby lead to an accident. The main pathophysiological mechanisms of sudden loss of control are disturbances of brain perfusion (eg, syncope with or without cardiac arrhythmia, sudden cardiac death due to ventricular fibrillation or asystole, stroke, etc.) and marked general weakness (eg, after major surgery or in heart failure). Patients with syncope and/or cardiovascular disease should be properly advised by their physicians about their fitness to drive, and restrictions should be documented.

Elevated plasma levels of asymmetric dimethylarginine and the risk for arrhythmic death in ischemic and non-ischemic, dilated cardiomyopathy - A prospective, controlled long-term study

INTRODUCTION

Elevated plasma levels of asymmetric dimethylarginine (ADMA), an inhibitor of NO synthase, are associated with adverse outcome. There is no data available, whether ADMA levels are associated with arrhythmic death (AD) in patients with ischemic cardiomyopathy (ICM) or non-ischemic, dilated cardiomyopathy (DCM).

METHODS AND RESULTS

A total of 110 ICM, 52 DCM and 30 control patients were included. Primary outcome parameter of this prospective study was arrhythmic death (AD) or resuscitated cardiac arrest (RCA). Plasma levels of ADMA were significantly higher in ICM (p < 0.001) and in DCM (p < 0.001) patients compared to controls. During a median follow-up of 7.0 years, 62 (32.3%) patients died. AD occurred in 26 patients and RCA was observed in 22 patients. Plasma levels of ADMA were not associated with a significantly increased risk of AD or RCA in ICM (hazard ratio (HR) = 1.37, p = 0.109) or in DCM (HR = 1.06, p = 0.848) patients. No significant association was found with overall mortality in ICM (HR = 1.39, p = 0.079) or DCM (HR = 1.10, p = 0.666) patients. Stratified Kaplan-Meier curves for ADMA levels in the upper tertile (>0.715 µmol/l) or the two lower tertiles (≤0.715 µmol/l) did not show a higher risk for AD or RCA (p = 0.221) or overall mortality (p = 0.548). In patients with left ventricular ejection fraction ≤ 35%, ADMA was not associated with AD or RCA (HR = 1.35, p = 0.084) or with overall mortality (HR = 1.24, p = 0.162).

CONCLUSIONS

Plasma levels of ADMA were elevated in patients with ICM or DCM as compared to controls, but were not significantly predictive for overall mortality or the risk for arrhythmic death.

Cardiac Autonomic Dysfunction in Multiple Sclerosis: A Systematic Review of Current Knowledge and Impact of Immunotherapies

Cardiac autonomic dysfunction (CAD) has been reported in patients with multiple sclerosis (MS). This systematic review summarizes the evidence for the types and prevalence of CAD in MS patients, as well as its association with MS type, disease characteristics, fatigue and immunotherapies used to treat MS. The analysis revealed that CAD is correlated with pathophysiological processes of MS, can trigger serious cardiovascular complications that may reduce life expectancy, and may have implications for treatment with immunotherapies, especially fingolimod. Numerous mainly small case-control or cohort studies have reported various measures of CAD (particularly heart rate variation) in MS patients, showing higher rates of abnormality versus controls. A smaller number of studies have reported on cardiac autonomic symptoms in MS, including orthostatic intolerance/dizziness in around 50% of patients. CAD also appears to be associated with disease duration and to be more common in progressive than relapsing-remitting MS. However, although a substantial evidence base suggests that assessing CAD in people with MS may be important, standardised methods to evaluate CAD in these patients have not yet been established. In addition, no studies have yet looked at whether treating CAD can reduce the burden of MS symptoms, disease activity or the rate of progression.

Importance of Diastolic Function for the Prediction of Arrhythmic Death: A Prospective, Observer-Blinded, Long-Term Study

BACKGROUND

Patients with ischemic or dilated cardiomyopathy and reduced left ventricular ejection fraction (LVEF) face a high risk for ventricular arrhythmias. Exact grading of diastolic function might improve risk stratification for arrhythmic death.

METHODS

We prospectively enrolled 120 patients with ischemic, 60 patients with dilated cardiomyopathy, and 30 patients with normal LVEF. Diastolic function was graded normal (N) or dysfunction grade I to III. Primary outcome parameter was arrhythmic death (AD) or resuscitated cardiac arrest (RCA).

RESULTS

Normal diastolic function was found in 23 (11%) patients, dysfunction grade I in 107 (51%), grade II in 31 (14.8%), and grade III in 49 (23.3%) patients, respectively. After an average follow-up of 7.0±2.6 years, AD or RCA was observed in 28 (13.3%) and 33 (15.7%) patients, respectively. Nonarrhythmic death was found in 41 (19.5%) patients. On Kaplan-Meier analysis, patients with dysfunction grade III had the highest risk for AD or RCA (P<0.001). This finding was independent from the degree of LVEF dysfunction and was observed in patients with LVEF≤35% (P=0.001) and with LVEF>35% (P=0.014). Nonarrhythmic mortality was the highest in patients with dysfunction grade III. This was true for patients with LVEF≤35% (P=0.009) or >35% (P<0.001). In an adjusted model for relevant confounding factors, grade III dysfunction was associated with a 3.5-fold increased risk for AD or RCA in the overall study population (hazard ratio=3.52; P<0.001).

CONCLUSIONS

Diastolic dysfunction is associated with a high risk for AD or RCA regardless if LVEF is ≤35% or >35%. Diastolic function grading might improve risk stratification for AD.

High incidence of atrial fibrillation after successful catheter ablation of atrioventricular nodal reentrant tachycardia: a 15.5-year follow-up

Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common type of supraventricular tachycardia. Slow pathway (SP) ablation is the treatment of choice with a high acute success rate and a negligible periprocedural risk. However, long-term outcome data are scarce. The aim of this study was to assess long-term outcome and arrhythmia free survival after SP ablation. In this study, 534 consecutive patients with AVNRT, who underwent SP ablation between 1994 and 1999 were included. During a mean follow-up of 15.5 years, 101 (18.9%) patients died unrelated to the procedure or any arrhythmia. Data were collected by completing a questionnaire and/or contacting patients. Clinical information was obtained from 329 patients (61.6%) who constitute the final study cohort. During the electrophysiological study, sustained 1:1 slow AV nodal pathway conduction was eliminated in all patients. Recurrence of AVNRT was documented in 9 patients (2.7%), among those 7 patients underwent a successful repeat ablation procedure. New-onset atrial fibrillation (AF) was documented in 39 patients (11.9%) during follow-up. Pre-existing arterial hypertension (odds ratio 2.61, 95% CI 1.14–5.97, p = 0.023), age (odds ratio 1.05, 95% CI 1.02–1.09, p = 0.003) and the postinterventional AH interval (odds ratio 1.02, 95% CI 1.00–1.04, p = 0.038) predicted the occurrence of AF. The present long-term observational study after successful SP ablation of AVNRT confirms its clinical value reflected by low recurrence and complication rates. The unexpectedly high incidence of new-onset AF (11.9%) may impact long-term follow-up and requires further clinical attention.

Sex difference in inappropriate therapy and survival among 1471 implantable cardioverter-defibrillator recipients

Introduction

To assess a potential relationship between sex and outcome in recipients of an implantable cardioverter‐defibrillator (ICD).

Methods and Results

All 1471 ICD recipients between 2000 and 2015 were sex‐related analyzed with the following outcome parameters: overall survival (OS), the occurrence of inappropriate and appropriate antitachycardia pacing (ATP), and shock therapy. We followed 1206 (82%) male and 265 (18%) female ICD recipients during 4.1 ± 3.6 and 4.3 ± 3.8 years, respectively, (P = .369). Kaplan‐Meier analysis revealed that there was no significant difference in OS between female and male patients (P = .132). After adjustment for relevant confounding factors in a multivariate model, sex remained a nonsignificant predictor of overall mortality (hazard ratio [male] = 1.11; P = .493). Negative binomial regression analysis revealed that women received less appropriate ATP therapy (rate ratio [RR] = 0.37; P = .043), whereas rates of appropriate shock therapy (RR = 1.95; P = .369) did not differ between women and men. No significant differences were observed in the occurrence of inappropriate ATP (RR = 1.22; P = .715) and inappropriate shock therapy (RR = 0.64; P = .121).

Conclusion

Female and male patients equally benefit from ICD therapy in terms of OS. Women are less likely to receive appropriate ATP therapy, whereas appropriate shock and inappropriate ATP and shock therapy are independent of sex.

GDF-15 is a better complimentary marker for risk stratification of arrhythmic death in non-ischaemic, dilated cardiomyopathy than soluble ST2

Growth differentiation factor (GDF)-15 and soluble ST2 (sST2) are established prognostic markers in acute and chronic heart failure. Assessment of these biomarkers might improve arrhythmic risk stratification of patients with non-ischaemic, dilated cardiomyopathy (DCM) based on left ventricular ejection fraction (LVEF). We studied the prognostic value of GDF-15 and sST2 for prediction of arrhythmic death (AD) and all-cause mortality in patients with DCM. We prospectively enrolled 52 patients with DCM and LVEF ≤ 50%. Primary end-points were time to AD or resuscitated cardiac arrest (RCA), and secondary end-point was all-cause mortality. The median follow-up time was 7 years. A cardiac death was observed in 20 patients, where 10 patients had an AD and 2 patients had a RCA. One patient died a non-cardiac death. GDF-15, but not sST2, was associated with increased risk of the AD/RCA with a hazard ratio (HR) of 2.1 (95% CI = 1.1-4.3; P = .031). GDF-15 remained an independent predictor of AD/RCA after adjustment for LVEF with adjusted HR of 2.2 (95% CI = 1.1-4.5; P = .028). Both GDF-15 and sST2 were independent predictors of all-cause mortality (adjusted HR = 2.4; 95% CI = 1.4-4.2; P = .003 vs HR = 1.6; 95% CI = 1.05-2.7; P = .030). In a model including GDF-15, sST2, LVEF and NYHA functional class, only GDF-15 was significantly associated with the secondary end-point (adjusted HR = 2.2; 95% CI = 1.05-5.2; P = .038). GDF-15 is superior to sST2 in prediction of fatal arrhythmic events and all-cause mortality in DCM. Assessment of GDF-15 could provide additional information on top of LVEF and help identifying patients at risk of arrhythmic death.

Risk of arrhythmic death in ischemic heart disease: a prospective, controlled, observer-blind risk stratification over 10 years

BACKGROUND

Risk of arrhythmic death is considered highest in ischemic heart disease with severe left ventricular ejection fraction (LVEF) reduction. Non-invasive testing should improve decision-making of prophylactic defibrillator (ICD) implantation.

DESIGN

We enrolled 120 patients with ischemic heart disease and LVEF < 50% and 30 control subjects without ischemic heart disease and normal LVEF. An initial assessment, a second assessment after 3 years and a final follow-up comprised of pharmacological baroreflex testing (BRS), short-term spectral [low-frequency (LF) to high-frequency (HF) ratio] and long-term time-domain analysis of heart rate variability (SDNN), exercise Microvolt T-wave alternans (MTWA) and others.

RESULTS

The median follow-up was 7·5 years. Resuscitated cardiac arrest and arrhythmic death due to ventricular arrhythmias ≥ 240/min was observed in 18% and 15% of patients, respectively. Cardiac death was observed in 28% of patients. The incidence of arrhythmic death and resuscitated cardiac arrest was identical in patients with ischemic heart disease with LVEF < 30% and ≥ 30%. No significant difference between subgroups with LVEF of < 30%, 30-39% and ≥ 40% was found either. MTWA, BRS, SDNN and LF to HF ratio failed to identify patients at risk of arrhythmic death in a multiple regression model.

CONCLUSIONS

Ischemic heart disease patients with LVEF < 30% and ≥ 30% face the same risk of arrhythmic death. Stratification techniques fail to identify high-risk patients. Therefore, the current practice to constrain prophylactic ICDs to patients with severely reduced LVEF seems to be insufficient.

Multiple autonomic and repolarization investigation of sudden cardiac death in dilated cardiomyopathy and controls

BACKGROUND

Prophylactic defibrillator implantation is recommended in dilated, nonischemic heart disease and left ventricular ejection fraction of ≤0.30 to 0.35. Noninvasive testing should improve accuracy in decision making of prophylactic defibrillator implantation.

METHODS AND RESULTS

We enrolled 60 patients (median age, 57 years) with dilated cardiomyopathy and left ventricular ejection fraction ≤0.50, and 30 control subjects (median age, 59 years) with left ventricular ejection fraction >0.50. The protocol included an initial assessment, a second assessment after 3 years, and a final follow-up: pharmacological baroreflex testing (baroreceptor reflex sensitivity), short-term spectral analysis of heart rate variability (low frequency/high frequency), and long-term time domain analysis (SD of all normal-to-normal R-R intervals), exercise microvolt T wave alternans, and signal-averaged ECG, and corrected QT-time. The median follow-up was 7 years. End points were cardiac death, resuscitated cardiac arrest, and arrhythmic death. Cardiac death was observed in 21 patients. Resuscitated cardiac arrest and arrhythmic death caused by ventricular tachyarrhythmias ≥240 per minute was observed in 7 and 10 patients, respectively. In the single time point analysis, microvolt T wave alternans, baroreceptor reflex sensitivity, and SD of all normal-to-normal R-R intervals at initial testing added significant information regarding cardiac death. Microvolt T wave alternans added information on resuscitated cardiac arrest or arrhythmic death at multiple time points (P<0.001). False-negative microvolt T wave alternans results were seen in 8% of patients.

CONCLUSIONS

Noninvasive testing and left ventricular ejection fraction could not reliably identify patients with dilated cardiomyopathy at risk of fatal ventricular tachyarrhythmias. Therefore, the strategy to confine prophylactic implantable cardioverter-defibrillator implantation to patients with dilated cardiomyopathy and severely reduced LV function should be reconsidered.

Implantable loop recorder in unexplained syncope: classification, mechanism, transient loss of consciousness and role of major depressive disorder in patients with and without structural heart disease

OBJECTIVE

To stratify mechanisms and predictors of unexplained syncope documented by an implantable loop recorder (ILR) in patients with and without structural heart disease (SHD).

DESIGN AND SETTING

Prospective study in consecutive patients of a university cardiac centre.

PATIENTS AND METHODS

An ILR was implanted in 70 patients (34 male/36 female, aged 55 (17) years) in whom syncope remained unexplained after thorough testing. SHD was present in 33 patients (ischaemic cardiomyopathy in 16, dilated cardiomyopathy in 9 and hypertrophic cardiomyopathy in 8) and absent in 37 patients (mean (SD) left ventricular ejection fraction 46 (4)% vs 61 (7)%, respectively).

RESULTS

A syncopal recurrence occurred during 16 (8) months in 30 patients (91%) with SHD and in 30 patients (81%) without SHD. Fifteen patients (45%) versus 19 patients (51%), respectively, had an ILR-documented arrhythmia at the time of recurrence which led to specific treatment. The remaining 15 patients (45%) with SHD and 11 patients (30%) without SHD had normal sinus rhythm at the time of the recurrence. On stepwise multivariate analysis only major depressive disorder was predictive for early recurrence during ILR follow-up (p = 0.01, hazard ratio = 3.35, 95% CI 1.1 to 7.1). Fifty seven per cent of patients with major depressive disorder had sinus rhythm during recurrence compared with 31% of patients without the disorder (p = 0.01). Conversely, no patient with major depressive disorder had asystole compared with 33% without (p<0.001).

CONCLUSIONS

The presence of SHD has little predictive value for the occurrence or type of arrhythmia in patients with unexplained syncope. Patients with major depressive disorder are prone to early recurrence of symptoms and have no evidence of arrhythmia in most cases. The ILR leads to specific treatment in half of all patients.

Core and skin surface temperature course after normothermic and hypothermic cardiopulmonary bypass and its impact on extubation time

BACKGROUND AND OBJECTIVE

Cardiopulmonary bypass is associated with temperature pertubations that influence extubation time. Common extubation criteria demand a minimum value of core temperature only. The aim of this prospective study was to test the hypothesis that changes in core and skin surface temperature are related to extubation time in patients following normothermic and hypothermic cardiopulmonary bypass.

METHODS

Forty patients undergoing cardiac surgery were studied; 28 patients had normothermic cardiopulmonary bypass (nasopharyngeal temperature >35.5 degrees C) and 12 had hypothermic cardiopulmonary bypass (28-34 degrees C). In the intensive care unit, urinary bladder temperature and skin surface temperature gradient (forearm temperature minus fingertip temperature: >0 degrees C = vasoconstriction, < or =0 degrees C = vasodilatation) were measured at 30-min intervals for 10 h postoperatively. At the same intervals, the patients were evaluated for extubation according to common extubation criteria.

RESULTS

On arrival in the intensive care unit the mean urinary bladder temperature was 36.8 +/- 0.5 degrees C in the normothermic group and 36.4+/-0.3 degrees C in the hypothermic group (P = 0.014). The skin surface temperature gradient indicated severe vasoconstriction in the both groups. The shift from vasoconstriction to vasodilatation was faster in normothermic cardiopulmonary bypass patients (138+/-65 min) than in patients after hypothermic cardiopulmonary bypass (186+/-61 min, P = 0.034). There was a linear relation between the time to reach a skin surface temperature gradient = 0 degrees C and extubation time (r2 = 0.56, normothermic group; r2 = 0.82, hypothermic group).

CONCLUSIONS

The transition from peripheral vasoconstriction to vasodilatation is related to extubation time in patients following cardiac surgery under normothermic as well as hypothermic cardiopulmonary bypass.

Ventricular tachycardia in arrhythmogenic right ventricular dysplasia/cardiomyopathy: Clinical presentation, risk stratification and results of long-term follow-up

BACKGROUND

Not all patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) are at risk for sudden cardiac death. The aim of the study was to evaluate the risk stratification in patients with ARVD/C.

METHODS AND RESULTS

Programmed ventricular stimulation (PVS) was performed in 34 ARVD/C patients. Twenty-two, 7 and 4 patients had documented sustained monomorphic ventricular tachycardia (smVT), non-smVT and ventricular fibrillation, respectively. One patient experienced syncope only. An implantable cardioverter defibrillator (ICD) was implanted in 11 patients inducible in smVT with hemodynamic compromise, in 4 patients with documented ventricular fibrillation and in one patient with non-smVT (194 ms tachycardia cycle length) (ICD group, n = 16). Ten patients were left without any antiarrhythmic therapy, 5 patients received antiarrhythmic drugs and 3 patients underwent successful VT ablation (non-ICD group, n = 18). Thirteen patients had an abnormal signal averaged ECG. During 6.5 +/- 2.4 years 69% of ICD patients received appropriate discharges and one non-ICD patient had a hemodynamically tolerated smVT recurrence (no sudden cardiac death in both groups). Comparison between the cycle lengths of clinical VT, induced VT and follow-up VT revealed a strong relationship (R = 0.62-0.88). On multivariate analysis abnormal signal averaged ECG and decreased left ventricular ejection fraction were statistically significant predictors for VT recurrence.

CONCLUSIONS

In ARVD/C the tachycardia cycle length of clinical VT, PVS-induced VT and follow-up VT correlate well implicating that a PVS-guided approach does not provide additional information. Spontaneous arrhythmia in combination with clinical presentation allows identification of patients in need for an ICD.

Prolonged asystole provoked by head-up tilt testing

We describe a patient with a history of neurocardiogenic syncopes who had a positive headup tilt test that resulted in an lasting asystole lasting 34 seconds. However, the previously carried out Schellong test with a 30-min phase of standing showed a normal result. The patient showed typical orthostatic symptoms while tilted at the angle of 75 degrees. Shortly before asystole occurred, heart rate variability showed high frequency bands, indicating vagal stimulation. The pathophysiology of neurocardiogenic syncope (NCS) in context with heart rate variability is discussed. This patient was successfully treated with propranolol. This case shows the utility of a provocative head-up tilt test in establishing the diagnosis of NCS. If the Schellong test is normal, still further examination by tilt-table test is indispensable.

Perspectives for core and skin surface temperature guided extubation in patients after normothermic cardiopulmonary bypass

OBJECTIVE

To investigate the relationship between changes in core and skin surface temperature and extubation time in patients following normothermic cardiopulmonary bypass (CPB).

DESIGN

Prospective observational study.

SETTING

Intensive care unit (ICU) of a university hospital.

PATIENTS

Patients admitted to the ICU after cardiac surgery.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Thirty-two patients undergoing cardiac surgery with the use of normothermic CPB were studied. In the ICU, urinary bladder temperature and skin surface temperature gradient (forearm temperature minus fingertip temperature) were measured at 30-min intervals for 10 h postoperatively. Every half-hour an anaesthesiologist, blinded to temperature measurements, checked the possibility of extubation. On arrival in the ICU the mean skin surface temperature gradient of the patients was 1.9+/-1.6 degrees C, indicating vasoconstriction of the dermal vessels (>0 degrees C = vasoconstriction, <0 degrees C = vasodilation) while the mean urinary bladder temperature was 36.8+/-0.4 degrees C. The change from thermoregulatory vasoconstriction to vasodilation (skin surface temperature gradient of 0 degrees C) was 137+/-49 min after arrival in the ICU. The mean time until extubation was 135+/-55 min after arrival in the ICU. There was a linear relation between a temperature gradient of 0 degrees C and extubation time, r(2)=0.49. Later, 181+/-67 min after arrival in the ICU, the urinary bladder temperature reached its maximum of 38.2+/-0.6 degrees C.

CONCLUSIONS

This study demonstrates that the transition period from peripheral vasoconstriction to vasodilation provides an opportunity for postoperative extubation.

Unexplained syncope in patients with structural heart disease and no documented ventricular arrhythmias: value of electrophysiologically guided implantable cardioverter defibrillator therapy

AIMS

To evaluate electrophysiologically guided implantable cardioverter defibrillator (ICD) therapy in patients with syncope, structural heart disease and no documented sustained ventricular tachycardia (sVT).

METHODS AND RESULTS

Programmed ventricular stimulation (PVS) was performed in 52 patients (age 62+/-10 years): 40 patients had ischaemic and 12 patients had idiopathic dilated cardiomyopathy. On PVS sVT and ventricular fibrillation were induced in seven and four patients, respectively, and two patients spontaneously experienced symptomatic sVT. These patients received an ICD (ICD group, n=13). Non-inducible patients were left on conventional therapy (non-ICD group, n=39). During 5+/-2.8 years five ICD patients received therapies, all appropriate. There were seven non-sudden deaths and overall survival analysis revealed no significant difference. Recurrent syncope occurred in five ICD and four non-ICD patients and did not correlate well with sVT. The positive and negative predictive values of PVS for tachyarrhythmias or sudden death were 36 and 98%, respectively.

CONCLUSION

Syncope per se does not necessarily herald a bad prognosis. PVS identifies high-risk patients. Induction of ventricular fibrillation with double or triple extrastimuli is of limited value. Patients with poor left ventricular function and bad clinical condition benefit most from an ICD. Syncope and sVT are not necessarily correlated during follow-up, which may merit consideration.

Electromagnetic interference by transcutaneous neuromuscular electrical stimulation in patients with bipolar sensing implantable cardioverter defibrillators: a pilot safety study

Neuromuscular electrical stimulation (NMES) is a frequently applied therapy for the treatment of pain and a therapeutic option to increase thigh muscle strength and endurance capacity in patients with heart failure. Electromagnetic interference (EMI) by the signals with sensing of ICDs is possible. Eight patients with subpectoral ICD systems and different transvenous bipolar sensing leads were subjected to electrical stimulation of the neck and shoulder and of the thighs using different stimulation algorithms. EMI with ventricular sensing was detectable in three of eight subjects. EMI occurred during stimulation of the neck (n = 2) and thigh (n = 2). EMI by NMES with atrial sensing was seen in two of four subjects with dual chamber ICDs. The safety of peripheral NMES has to be individually tested as EMI can also occur in ICD patients with bipolar sensing.

Can hypocapnia reduce cerebral embolization during cardiopulmonary bypass?

BACKGROUND

Cerebral embolization is a major cause of central nervous dysfunction after cardiopulmonary bypass. Experimental studies demonstrate that reductions in arterial carbon dioxide tension (PaCO2) can reduce cerebral embolization during cardiopulmonary bypass. This study examined the effects of brief PaCO2 manipulations on cerebral embolization in patients undergoing cardiac valve procedures.

METHODS

Patients were prospectively randomized to either hypocapnia (PaCO2 = 30 to 32 mm Hg, n = 30) or normocapnia (PaCO2 = 40 to 42 mm Hg, n = 31) before aortic cross-clamp removal. With removal of the aortic cross-clamp embolic signals were recorded by transcranial Doppler ultrasonography for the next 15 minutes.

RESULTS

Despite significant differences in PaCO2, groups did not differ statistically in total cerebral emboli counts. The mean number of embolic events was 107 +/- 100 (median, 80) in the hypocapnic group and 135 +/- 115 (median, 96) in the normocapnic group, respectively (p = 0.315).

CONCLUSIONS

Due to the high between-patient variability in embolization, reductions in PaCO2 did not result in a statistically significant decrease in cerebral emboli. In contrast to experimental studies, the beneficial effect of hypocapnia on cerebral embolization could not be demonstrated in humans.

The use of the antioxidant tirilazad mesylate in human liver transplantation: is there a therapeutic benefit?

OBJECTIVES

To test the hypothesis whether in patients undergoing liver transplantation the antioxidant tirilazad mesylate can reduce hepatic ischaemia-reperfusion injury and improve postoperative outcome.

DESIGN

Prospective, randomised, placebo controlled trial.

SETTING

University hospital.

PATIENTS

20 patients were randomised to receive either tirilazad mesylate or placebo (saline).

INTERVENTIONS

Patients in the tirilazad group (n = 10) received four intravenous infusions of tirilazad at 6-h intervals (men 3 mg/kg, women 3.75 mg/kg) after the induction of anaesthesia. The other patients (n = 10) served as controls.

MEASUREMENTS AND RESULTS

Plasma levels of malonaldehyde (MDA) were determined after the induction of anaesthesia prior to the infusion of tirilazad (baseline), during the anhepatic period, and 5 min and 24 h after reperfusion. Postoperatively, alanine aminotransferase, aspartate aminotransferase, prothrombin time, and serum cholinesterase were determined daily for 1 week. Compared to baseline, plasma MDA levels did not significantly change during the anhepatic period and after reperfusion and they did not differ between groups. Postoperative liver enzymes and prothrombin time did not differ between groups, but on the first (p = 0.03) and second (p = 0.01) postoperative day cholinesterase levels were significantly higher in tirilazad-treated patients than in control patients. For neither length of stay in the intensive care unit nor hospital stay were any differences observed between groups.

CONCLUSIONS

In patients undergoing liver transplantation, tirilazad does not improve overall outcome. Whether the higher cholinesterase levels on the first 2 postoperative days in tirilazad treated patients indicates an earlier recovery of liver function remains to be tested.

[Protein catabolism after lung transplantation and heart transplantation]

Any surgical intervention is associated with an activation of protein catabolism, the extent of which is dependent on the severity of surgical trauma. There is a paucity of reports on protein catabolism after transplantation of chest organs (lung transplantation (LTX) and heart transplantation (HTX)). The aim of the present study was to quantify and compare the extent of postoperative protein catabolism and associated metabolic perturbations in patients after LTX and HTX. Eighteen consecutive patients after LTX and 15 consecutive patients after HTX who required postoperative intensive care for more than 4 days, constituted the study population. The nitrogen balance (assessed on the basis of the urea nitrogen production rate and nitrogen intake) was assessed retrospectively and correlated with insulin requirements, immunosuppression and the clinical course. Within the first 5 days the nitrogen balance became progressively negative in both groups, reaching a maximum on the 5th day. Thereafter the nitrogen balance of patients following LTX remained negative, whereas the nitrogen balance of patients following HTX tended to improve. The evolution of nitrogen balance significantly differed between both groups (p < 0.01). The mean nitrogen loss was -0.29 +/- 0.17g/kg BW/day after LTX versus -0.22 +/- 0.12g/kg BW/day after HTX. Smaller amounts of glucocorticoids were used for immunosuppression in patients after HTX than in patients after LTX; nevertheless, heart transplant recipients required higher doses of insulin to maintain normoglycemia. A regression analysis revealed that the duration of stay at the intensive care unit (p < 0.001) and the amount of glucocorticoids (p < 0.01) negatively affected the nitrogen balance, whereas an increased protein intake (p < 0.001) exerted a positive effect. Compared to other major surgical procedures, protein catabolism is excessively elevated in patients after thoracic transplantation. Immunosuppressive therapy with glucocorticoids contributes to protein degradation; the nitrogen balance after LTX is more negative than that after HTX because of higher glucocorticoid requirements following LTX. More aggressive nutritional intervention and especially an increased nitrogen intake might help to reduce protein losses in these patients.

Nitric oxide concentration in the gas phase of the gastrointestinal tract in man

Nitric oxide (NO) has been implicated in various aspects of physiological regulation in the gastrointestinal tract. Hence, measurement of luminal NO concentrations is of interest for studying physiological and pathophysiological alterations in NO generation; however, at present, no reliable measurement techniques are available. Here we describe novel approaches for measurement of NO concentrations directly in the gas phase of the stomach and colon in healthy subjects and patients. Studies were conducted in young healthy volunteers (n = 13), intensive care patients (n = 8) and patients undergoing gastroscopy (n = 8) or colonoscopy (n = 8). NO concentrations were measured by chemolumininescence detection in air obtained through a nasogastric tube, after inflation into the stomach of a defined volume of air, or directly in the air suctioned from the endoscope. The mean NO concentration obtained from the stomach of healthy volunteers studied under baseline conditions was 18.0 +/- 2.8 (SEM) p.p.m. Day-to-day reproducibility of NO measurements was high. Tube feeding with a nitrite- and nitrate-free feeding solution left gastric NO concentrations unchanged, but standardized bicycle exercise caused an approximately 30% decrease in NO levels. NO concentrations in intensive care patients were approximately 2 log cycles lower than in healthy volunteers. NO levels in the colon were similar to those in the stomach. We have described two readily applicable techniques for direct, uncontaminated measurement of NO concentrations in the lumen of the gastrointestinal tract. Our finding of a striking reduction in gastric NO concentrations in intensive care patients requires further study.