Heart rate variability for rapid risk stratification of emergency patients with malignant disease.

INTRODUCTION: Neoplasms are the second most common diseases in western countries. Many patients with malignant diseases repeatedly present themselves in the emergency department (ED). Due to limited capacities, appropriate risk stratification strategies for cancer patients have to be developed. This study assesses if deceleration capacity (DC) of heart rate as a parameter of heart rate variability predicts mortality in emergency patients with malignant diseases. METHODS: Prospectively, 140 adults with different entities of malignant diseases who presented in the medical ED were included. Primary and secondary endpoints were intrahospital mortality and mortality within 180 days, respectively. We calculated DC from short-term ECG readings of the surveillance monitors. Additionally, the Modified Early Warning Score (MEWS) and laboratory parameters such as white blood cells (WBC), lactate dehydrogenase, serum hemoglobin, and serum creatinine were determined. RESULTS: The median age of the patients was 65 ± 14 years. 19.3% of the patients died within the hospital stay and 57.9% died within 180 days. DC and WBC were independent predictors of intrahospital death reaching a hazard ratio (HR) of 0.79 (95% confidence interval (CI) 0.63-0.993, p = 0.043) and of 1.00 (95% CI 1.00-1.00, p = 0.003), respectively. DC and serum creatinine independently predicted death within 180 days (HR 0.90, 95% CI 0.82-0.98, p = 0.023 and HR 1.41, 95% CI 1.05-1.90, p = 0.018, respectively). CONCLUSION: Deceleration capacity of heart rate is suitable for rapid risk assessment of emergency patients with malignant diseases.

Point-of-care testing of cardiac autonomic function for risk assessment in patients with suspected acute coronary syndromes.

BACKGROUND: Impaired cardiac autonomic function has been linked to adverse outcomes in patients with acute coronary syndromes (ACS) but is not included in clinical risk models. This is the first study to investigate whether point-of-care testing of cardiac autonomic function by means of short-term deceleration capacity (DC) of heart rate improves risk assessment in patients with suspected ACS. METHODS: 1821 patients with suspected ACS were prospectively enrolled if they were older than 17 years and in sinus rhythm. Short-term DC was automatically assessed from monitor recordings at hospital admission. The Global Registry of Acute Coronary Events (GRACE) score was used as gold standard risk predictor. Primary endpoint was the composite of intrahospital and 30-day mortality. Secondary endpoint was 180-day mortality. RESULTS: Of the 1,821 patients with suspected ACS, 28 (1.5%) and 60 (3.3%) reached the primary and secondary endpoints, respectively. DC was a highly significant predictor of both endpoints, yielding areas under the curve (AUC) of 0.784 (95% CI 0.714-0.854) and 0.781 (0.727-0.832) (p < 0.001 for both), respectively. Implementing DC into the GRACE-risk model leads to a significant increase of the C-statistics from 0.788 (0.703-0.874) to 0.825 (0.750-0.900; p < 0.01 for difference) and from 0.814 (0.759-0.864) to 0.851 (0.808-0.889; p < 0.01 for difference) for the primary and secondary endpoints, respectively. Stratification by dichotomized DC was especially powerful in patients with GRACE score <140. CONCLUSIONS: In patients with suspected ACS, point-of-care testing of cardiac autonomic function by means of DC is feasible and improves risk assessment by the GRACE score. CLINICAL TRIAL REGISTRATION: Clinicaltrials.gov NCT01486589.

Insertable cardiac monitors after cryptogenic stroke--a risk factor based approach to enhance the detection rate for paroxysmal atrial fibrillation.

BACKGROUND AND PURPOSE: Recently, the CRYSTAL AF trial detected paroxysmal atrial fibrillation (AF) in 12.4% of patients after cryptogenic ischaemic stroke (IS) or cryptogenic transient ischaemic attack (TIA) by an insertable cardiac monitor (ICM) within 1 year of monitoring. Our aim was (i) to assess if an AF risk factor based pre-selection of ICM candidates would enhance the rate of AF detection and (ii) to determine AF risk factors with significant predictive value for AF detection. METHODS: Seventy-five patients with cryptogenic IS/TIA were consecutively enrolled if at least one of the following AF risk factors was present: a CHA2DS2-VASc score ≥4, atrial runs, left atrium (LA) size >45 mm, left atrial appendage (LAA) flow ≤0.2 m/s, or spontaneous echo contrast in the LAA. The electrocardiographic and echocardiographic criteria were chosen as they have been repeatedly reported to predict AF; the same applies for four of the six items of the CHA2DS2-VASc score. The study end-point was the detection of one or more episodes of AF (≥2 min). RESULTS: Seventy-four patients underwent implantation of an ICM; one patient had AF at the date of implantation. After 6 months, AF was detected in 21/75 patients (28%), after 12 months in 25/75 patients (33.3%). 92% of AF episodes were asymptomatic. LA size >45 mm and the presence of atrial runs were independently associated with AF detection [hazard ratio 3.6 (95% confidence interval 1.6-8.4), P = 0.002, and 2.7 (1.2-6.7), P = 0.023, respectively]. CONCLUSIONS: The detection rate of AF is one-third after 1 year if candidates for an ICM after cryptogenic IS/TIA are selected by AF risk factors. LA dilation and atrial runs independently predict AF.

Geometric correlations and breakdown of mesoscopic universality in spin transport.

We construct a unified semiclassical theory of charge and spin transport in chaotic ballistic and disordered diffusive mesoscopic systems with spin-orbit interaction. Neglecting dynamic effects of spin-orbit interaction, we reproduce the random matrix theory results that the spin conductance fluctuates universally around zero average. Incorporating these effects into the theory, we show that geometric correlations generate finite average spin conductances, but that they do not affect the charge conductance to leading order. The theory, which is confirmed by numerical transport calculations, allows us to investigate the entire range from the weak to the previously unexplored strong spin-orbit regime, where the spin rotation time is shorter than the momentum relaxation time.