purpose: hypercapnia increases minute ventilation (v’e) with little effect on heart rate (hr), whereas hypoxia may increase hr without affecting v’e. however, the effects of hypercapnia and hypoxia on both heart rate variability (hrv) and the clustering of heart beats during spontaneous breathing (respiratory sinus arrhythmia – rsa), are not clear. methods: in this study, 10 human volunteers br...

KEY POINTS Cardiac vagal tone is a strong predictor of health, although its central origins are unknown. Respiratory-linked fluctuations in cardiac vagal tone give rise to respiratory sinus arryhthmia (RSA), with maximum tone in the post-inspiratory phase of respiration. In the present study, we investigated whether respiratory modulation of cardiac vagal tone is intrinsically linked to post-in...

OBJECTIVE To assess the use of the active orthostatic stress test for detecting vagal dysfunction in patients with Chagas' disease with preserved overall systolic function, and to compare it with the respiratory sinus arrhythmia test. METHODS Sixty-one chagasic patients (Ch) and 38 nonchagasic (NCh) patients with no significant evidence of heart disease or systemic diseases underwent Doppler ...

The present longitudinal study examined relations between respiratory sinus arrhythmia (RSA) development and social responsiveness characteristics associated with autism spectrum disorders. Group-based developmental trajectory modeling was used to characterize RSA development patterns in 106 typically developing children across 5, 10, 24, 36, and 48 months of age. A two-group model fit of RSA d...

A method for the accurate time-domain characterization of respiratory sinus arrhythmia (RSA) pattern is presented and applied to two groups of healthy subjects to lay the baseline of RSA patterns and to underlay their features: response to standing, stability in successive recordings, and individuality of the shape of RSA pattern. RSA pattern is evaluated by selective averaging of heart rate (H...

The amplitude of respiratory sinus arrhythmia (RSA) was measured in eight healthy young male students with special reference to the effect of tidal volume (Vt). Under simultaneously controlled respiratory frequency and Vt, the heart rate variability (HRV) of the subjects was measured. While the respiratory frequency was adjusted to either 0.25 or 0.10 Hz, the Vt was controlled at 13 different v...

Resting respiratory sinus arrhythmia (RSAREST) indexes important aspects of individual differences in emotionality. In the present investigation, the authors address whether RSAREST is associated with tonic positive or negative emotionality, and whether RSAREST relates to phasic emotional responding to discrete positive emotion-eliciting stimuli. Across an 8-month, multiassessment study of firs...

Background: Bradycardias have been reported (rarely) associated with acute cholecystitis. Data extraction: We here present the first reported case in which acute cholecystitis was associated with self-limited episodes of slow junctional escape (40/min) and marked sinus arrhythmia. Conclusion: Brady-arrhythmias have been associated with acute biliary disease consistent with the putative mechanis...