The aim of this study was to assess the influence of breathing pattern on the reproducibility of the most commonly used heart rate and blood pressure variability parameters and baroreflex indices. 5-5 min ECG and blood pressure recordings were made and repeated for 10 healthy volunteers in supine rest on 10 consecutive days during spontaneous and 6 min(-1) patterned breathing. We investigated the following parameters: mean RR interval (RRI); the standard deviation of RR intervals (SDRR); the root mean square of successive differences in RRI (RMSSD); the percentage of RRIs which differed by 50% from the proceeding RRI (PNN50); mean systolic arterial pressure (SAP); the standard deviation of SAP (SAP SD); mean mean arterial pressure (MAP); mean diastolic blood pressure (DAP) and baroreflex indices from spontaneous sequence method (upBRS and downBRS) and from cross spectral analysis (LF alpha, HF alpha). To assess reproducibility for each parameter within- and between-subject variability values were calculated and the ratio of within- and between-subject variability was assessed. In addition, we calculated intraclass correlation coefficient (ICC). Compared to spontaneous respiration during 6 min(-1) patterned breathing the heart rate and blood pressure variability increased; upBRS, LF alpha and HF alpha increased, downBRS did not change. However, ICC showed good reproducibility for most parameters, which did not improve further with controlled breathing. In conclusion, respiration had a strong influence on the most widely used cardiovascular autonomic parameters. The controlling of breathing did not result in consistent improvement in their reproducibility.

Erdheim-Chester's disease is a rare multisystem xanthogranulomatosis, afflicting the skeletal system with the occasional involvement of soft tissues. We delineate an unusual case of a cardiac variant of Erdheim-Chester's disease presenting with pericardial effusion and as a collision with a synchronous orbital manifestation. We describe our diagnostic pathway and propose a novel treatment option involving nonsteroidal anti-inflammatory drugs. The role of cyclo-oxygenase in the disease process and inhibition thereof by NSAIDs is hypothesized and discussed.

Our study indicates that traditional sphygmomanometer based values can safely be replaced by values yielded by finger plethysmography, combined with brief orthostatic challenges and that P300 as a cognitive marker cannot be used to assess volume loss.

No abstract

Acute, severe hypovolemia is a medical emergency. Traditional vital sign parameters allow no optimal triage. High predictive power of finger plethysmography-based stroke volume (SV) and pulse pressure (PP) was recently suggested. To assess the performance of the PP and SV parameters, lower body negative pressure of -40 mmHg, than -60 mmHg -corresponding to moderate and severe central hypovolemia -was applied in 22 healthy males (age 35 ± 7 years). Slow breathing induced fluctuations in the above indices, characterized by stroke volume variability (SVV), and pulse pressure variability (PPV), were assessed. Responses in heart rate (HR) and shock index (SI) were also studied. Discriminative capacity of these parameters was characterized by the area under the ROC (receiver operating characteristic) curves (AUC). Results: In comparison of baseline to severe central hypovolemia SV, PP, HR and SI showed good discriminating capacity (AUC 99%, 88%, 87% and 93%, respectively). The discriminating capacity of SVV and PPV was poor (77% and 70%, respectively). In comparison of moderate and severe hypovolemia, the discriminating capacity of the studied parameters was uniformly limited. Conclusions: Plethysmography-based SV and PP parameters can be used to detect acute severe volume loss. Sensitive parameters discriminating moderate and severe central hypovolemia are still lacking.

No abstract

The time honored ancient reflex tests, the Valsalva and Müller maneuvers are still popular in the everyday clinical practice. These maneuvers are capable of imitating both trivial situations and significant pathological conditions. The Valsalva maneuver is still frequently used for the assessment of autonomic neuropathy. Addition of continuous noninvasive blood pressure monitoring allows assessment of both cardiac vagal and sympathetic driven peripheral vasomotor responses. The Müller maneuver has recently gained renewed popularity in simulating episodes of obstructive sleep apnea (OSA). Continuous monitoring of arterial pressure and muscle sympathetic nerve activity (MSNA) casts light on the close relationship between OSA and circulatory abnormalities.

Orthostatic intolerance and postural tachycardia are common complaints, often caused by hypovolemia, antihypertensive medications, diuretics or alcohol. These symptoms could also be related to autonomic failure. Although upright posture renders patients more susceptible to provocation of supraventricular tachyarrhythmias in the electrophysiologic laboratory, orthostasis by itself seldom enough for the induction of such arrhythmias. The authors hereby present a patient, whose AV nodal reentry tachycardia could be provoked by head-upright tilting. Vagal maneuvers could terminate the tachycardia by decreasing the conduction in the slow anterograde pathway, however these maneuvers were successful only after assuming supine posture. The authors' report illustrates the role of autonomic influences, and the mechanism of vagal maneuvers in terminating this common arrhythmia.