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Table 2 Demographic, PSG, and ECG characteristics in the reference population

From: QTc prolongation is associated with severe desaturations in stroke patients with sleep apnea

Demographics

n/Median (%/IQR)

ECG characteristics

Median (IQR)

Patients (male)

18 (72.2)

RR interval (ms)

887.1 (808.1–998.3)

Age (years)

48.3 (46.2–49.6)

PQ interval (ms)

179.7 (164.1–191.6)

BMI (kg/m2)

35.1 (31.0–37.9)

QRS interval (ms)

93.8 (85.0–102.1)

Atrial fibrillation

1 (5.6)

QT interval (ms)

390.6 (359.4–410.2)

COPD

0 (0)

QTc interval (ms)

405.0 (392.7–420.8)

Dyslipidemia

6 (33.3)

Nocturnal HVR

Median (IQR)

Hypertension

7 (38.9)

SDNN (ms)

38.2 (17.7–54.2)

Smoker

3 (16.7)

RMS-SD (ma)

29.7 (14.7–52.5)

PSG characteristics

Median (IQR)

LF (m2)

563.2 (180.6–1456.1)

AHI (events/h)

29.8 (24.3–37.8)

HF (m2)

320.5 (79.1–788.4)

ODI (events/h)

25.1 (13.2–40.7)

LF/HF

2.1 (1.3–3.6)

Desaturation duration (s)

30.0 (21.1–40.0)

VLF (m2)

186.7 (91.9–481.5)

Desaturation depth (%)

4.7 (3.4–7.9)

SD1 (ms)

21.9 (10.4–37.2)

TST (min)

339.8 (321.0–368.5)

SD2 (ms)

44.5 (23.7–67.7)

Arousal index (events/h)

28.5 (23.9–41.2)

SD1/SD2

2.1 (1.8–2.7)

  1. PSG polysomnography, ECG electrocardiogram, n number of patients, BMI body mass index, COPD chronic obstructive pulmonary disease, IQR interquartile range, AHI apnea–hypopnea index, ODI oxygen desaturation index, TST total sleep time, HRV heart rate variability, SDNN standard deviation of NN intervals, RMS-SD root mean square of successive RR interval differences, LF absolute power of the low-frequency band, HF absolute power of the high-frequency band, LF/RF ratio of LF-to-HF power, VLF absolute power of the very-low-frequency band, SD1 Poincaré plot standard deviation perpendicular the line of identity, SD2 Poincaré plot standard deviation along the line of identity, SD1/SD2 ratio of SD1-to-SD2