Relation between heart rate and pulse transit time during paced respiration

Area of Science:

• Cardiovascular Physiology
• Biomedical Engineering
• Non-invasive Monitoring

Background:

• Pulse transit time (PTT) is a non-invasive measure of arterial wave travel time.
• PTT is influenced by factors like heart rate, blood pressure, and arterial compliance.
• Quantitative data on factors influencing PTT, particularly its relationship with cardiac intervals, are limited.

Purpose of the Study:

• To investigate the relationship between cardiac beat-to-beat interval (RR) and pulse transit time (PTT).
• To quantify the correlation between RR interval and PTT changes.
• To determine the temporal relationship between variations in RR interval and PTT.

Main Methods:

• Analysis of PTT and RR intervals in 15 healthy subjects.
• Utilized paced respiration to induce changes in both PTT and RR intervals.
• Employed cross-correlation function to quantify the relationship between PTT and RR intervals.

Main Results:

• Significant changes in PTT (mean range 14 +/- 5 ms) and RR interval (mean range 241 +/- 102 ms) were observed.
• A strong positive correlation (r = +0.69, p < 0.01) was found between PTT and RR intervals.
• PTT changes lagged behind RR interval changes by approximately 3.17 +/- 0.76 beats.

Conclusions:

• A significant relationship exists between beat-to-beat interval and pulse transit time.
• Changes in cardiac rhythm (RR interval) precede corresponding changes in arterial pulse wave velocity (PTT).
• The observed relationship suggests PTT is a sensitive indicator of cardiac interval variations, though not synchronized.