Effects of variation in posture and respiration on RSA and pre‐ejection period

Abstract

The extent to which variation in posture and respiration can confound pre-ejection period and respiratory sinus arrhythmia (RSA) as indices of cardiac sympatho-vagal activity was examined. Within-subjects changes in these measures were assessed in 36 subjects during different postures and (paced) respiratory frequencies. Changes from supine to sitting to standing led to reduced RSA values and longer pre-ejection periods, reflecting the known decrease in vagal but not the increase of sympathetic activity. Multilevel path analysis showed that within-subjects changes in sympatho-vagal balance were faithfully reflected by changes in interbeat interval, but imperfectly by changes in RSA and pre-ejection period. It was concluded that pre-ejection period should be stratified for posture and RSA for respiratory frequency to reliably index changes in sympatho-vagal balance when these factors are prone to change (e.g., during 24-h ambulatory recording)

Comparing low frequency heart rate variability and preejection period: Two sides of a different coin

“…Studies using manipulations known to increase cardiac sympathetic activity like mental stress and exercise currently suggest that the PEP outperforms the LF/HF ratio as an index of sympathetic control. Mental or emotional stress increases the LF power in some studies (Langewitz & Ruddel, 1989) but not in all (Hoshikawa & Yamamoto, 1997;Tulen, Boomsma, & Veld, 1999), whereas these stressors systematically shorten the PEP de Geus, Kupper, Boomsma, & Snieder, 2007;Houtveen et al, 2005;Sherwood et al, 1990). Furthermore, cardiac sympathetic activation induced by exercise sometimes evokes a decrease in LFnu power rather than the expected increase (Ahmed, Kadish, Parker, & Goldberger, 1994), whereas systematic and dose-dependent shortening of the PEP is seen during exercise (Houtveen, Rietveld, & de Geus, 2002;Smith et al, 1989).…”

“…From the ECG and the dZ, we obtained the heart period time series and respiration signal (Goedhart et al, 2007;Houtveen et al, 2005). In keeping with PEP scoring, mean LF and HF powers were computed across the entire coded period.…”

“…We next compared the LF/HF ratio, both within and between subjects, to an alternative measure of cardiac sympathetic control, the preejection period (PEP), which can be obtained by ambulatory recording of the thoracic impedance cardiogram Riese et al, 2003). Changes in PEP reflect changes in b-adrenergic inotropic drive to the left ventricle, provided subjects are compared in the same posture (Houtveen, Groot, & de Geus, 2005;Sherwood et al, 1990). If the LF/HF ratio is a valid measure of cardiac sympathetic control, it should show a negative correlation to the PEP, such that longer PEPs are associated with lower LF/HF ratios.…”

Effects of Antidepressants, but not Psychopathology, on Cardiac Sympathetic Control: A Longitudinal Study

“…Postural changes can cause changes in PEP that are partially independent of changes in sympathetic control (Houtveen et al, 2005). To avoid confounding of PEP by posture, three periods were identified in the total recording period in which subjects did not change posture and were quietly sitting for a prolonged period.…”

Ambulatory measurement of the ECG T‐wave amplitude

“…The literature supports changes in PEP as a valid measure of SNS-induced changes in contractility of the left ventricle (Berntson et al, 1994;Goedhart, Kupper, Willemsen, Boomsma, & de Geus, 2006;Harris, Schoenfeld, & Weissler, 1967;Houtveen, Groot, & Geus, 2005;Krzeminski et al, 2000;Mezzacappa, Kelsey, & Katkin, 1999;Miyamoto et al, 1983;Nelesen, Shaw, Ziegler, & Dimsdale, 1999;Newlin & Levenson, 1979;Richter & Gendolla, 2009;Schachinger, Weinbacher, Kiss, Ritz, & Langewitz, 2001;Sherwood, Allen, Obrist, & Langer, 1986;Smith et al, 1989;Svedenhag, Martinsson, Ekblom, & Hjemdahl, 1986;Vrijkotte et al, 2004;Williams, Puddey, Beilin, & Vandongen, 1993;Winzer et al, 1999). A large advantage of the PEP is that it can be measured outside the confines of a hospital or laboratory setting by using ambulatory monitoring devices (Nakonezny et al, 2001;Sherwood, McFetridge, & Hutcheson, 1998;Wilhelm, Roth, & Sackner, 2003;Willemsen et al, 1996).…”