What question did this study set out to answer?

The study aims to clarify the effects of pathological respiratory patterns on heart rate turbulence in obstructive sleep apnea syndrome (OSAS).

March 24, 2026

Effects of pathological respiratory pattern on heart rate turbulence in sleep apnea

Key Result

Heart rate turbulence late deceleration (TS) is significantly higher during obstructive apnea episodes than normal respiratory phases (7.4±5.4 vs. 2.7±1.2, p<0.001) in severe sleep apnea.

Key Points

The study aims to clarify the effects of pathological respiratory patterns on heart rate turbulence in obstructive sleep apnea syndrome (OSAS).
Analyzed heart rate turbulence using polysomnography data from patients with severe OSAS.
Evaluated heart rate fluctuations following isolated ventricular premature complexes during normal and obstructive apnea episodes.
Compared early rate acceleration (TO) and late deceleration (TS) indexes across normal and obstructive apnea phases.
TO values during obstructive apnea did not differ significantly from normal respiratory periods.
TS during obstructive apnea was significantly higher than during normal phases (7.4 vs. 2.7, p<0.001).
The findings indicate a paradoxical increase in TS during obstructive apnea episodes followed by a decrease in normal phases.

Structured PICO

Does obstructive apnoea pattern alter heart rate turbulence compared to normal respiratory pattern in patients with severe OSAS?

Population

20 patients with severe obstructive sleep apnea syndrome (OSAS), mean age 62±14

Intervention

Obstructive apnoea pattern (OA) during polysomnography

Comparator

Normal respiratory pattern (NR) epochs during the same polysomnography

Outcome

Heart rate turbulence (HRT) indexes: early rate acceleration (TO) and late deceleration (TS)surrogate

Obstructive apnea episodes paradoxically increase the late deceleration index of heart rate turbulence compared to normal respiratory phases in severe OSAS patients, reflecting complex autonomic responses.

Main Result

Absolute Event Rate: 0% vs 0%

Abstract

Although baroreflex sensitivity (BRS) impairments are involved in cardiovascular disease's development in OSAS, the mechanism underlying this derangement is rather unknown. BRS can be non-invasively assessed by heart rate turbulence (HRT) analysis. This is the first study separately assessing HRT during normal (NR) and obstructive apnoea pattern (OS) with the aim to describe the effects of pathological respiratory pattern on HRT in OSAS. HRT is characterized by an early rate acceleration (TO) and a late deceleration (TS) indexes describing heart rate fluctuations following spontaneous isolated ventricular premature complexes. Results on 20 polysomnography of severe OSAS pts. (age 62±14) showed that, while the TO during OA is not significantly different from those of NR epochs (-0.3±1.8 vs. -0.4±1.2), the TS during OA is very significantly higher than in NR phases (7.4±5.4 vs. 2.7±1.2 , p<0.001 Wilcoxon matched pairs test). This novel finding showed a not previously known paradoxical TS increasing during OA episodes followed by a marked decrease during subsequent NR phases. This can be related to repetitive brief inspiration against an obstructed airway, generating intrathoracic pressure changes, that in the initial phase results in marked hypotension and a paradoxical reduction sympathetic activity while, toward the end generates a gradually increasing sympathetic activity. Such deeper understanding of the integrated autonomic response in different OSA pathophysiological conditions could be useful to address an overall cardiorespiratory assessment and treatment in sleep-related breathing disorders.

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