Effect of Acupuncture on Heart Rate Variability: A Systematic Review

Table 3

Summary of extracted RCTs.

Authors (year); and origin	Design sample size Conditions	Intervention (regimen)	Heart rate variability	Main results of intergroup differences	Risk of bias
Kwak et al. [22],; South Korea	Parallel; 42 healthy students with examination stress	(A) AT (𝑛=14); (B) sham Tx ( relaxation therapy, 𝑛=14); (C) Co (no Tx, 𝑛=14)	(1) HRT (beats/min); (2) SDNN (ms); (3) SDSD (ms); (4) LF norm (n.u.); (5) HF norm (n.u.); (6) LF/HF	(1) A→, B→, C↓ when comparing between examination and normal time: 𝑃<0.05; (1), (4), and (6) A↓, B→, C→ before and after examination: 𝑃<0.05; (2) A↑, B→, C→ at normal time: 𝑃<0.05; (5) A↑, B→, C→ before and after examination: 𝑃<0.05	U, U, U, U, U
Huang et al. [23],; Taiwan	Parallel; 111 healthy subjects	(A) AT (P6, 20 min on both forearms, 𝑛=39); (B) sham AT ( sham acupuncture at dummy points, 20 min, 𝑛=38); (C) Co: no Tx, 𝑛=34)	(1) Mean RR interval (ms); (2) SD of RR interval (ms); (3) coefficient of variation (%); (4) HF norm (nu); (5) LF norm (nu); (6) LF/HF	(1) A↑, B↑, C→: 𝑃<0.05; (4) A↑, B→, C→: 𝑃<0.05	U, N, N, N, N
Chang et al. [24],; Taiwan	Crossover, 15 healthy subjects	(A) EA (2 Hz, 30 min, 𝑛=15); (B) Sham EA (minimal penetration on nonacupuncture point, no electric stimulation, 𝑛=15); (C) EA plus atropine injection; sessions A, B, C in a randomized order with 3 days between sessions	(1) LF/HF; (2) LF; (3) HF	(1) A↑, B→: NS; (2), (3) A→, B→: NS	U, N, Y, U, U
Chang et al. [25],; Taiwan	Crossover, 15 healthy subjects	(A) EA (2 Hz at Zusanli, 30 min, 𝑛=15); (B) EA (2 Hz at Shousanli, 30 min, 𝑛=15); (C) EA (100 Hz at Zusanli, 30 min, 𝑛=15); (D) EA (100 Hz at Shousanli, 30 min, 𝑛=15); (E) sham EA (minimal penetration on nonacupuncture point, no electric stimulation, 𝑛=15); Sessions in a randomized order with 3 days between sessions	(1) LF/HF; (2) LF; (3) HF	(1) A↑ during and after EA, B→, C→, D→, E→: NS; (2) A↑ during and after EA, B→, C→, D→, E→: NS; (3) A↓ during and after EA, B→, C→, D→, E→: NS	U, N, Y, U, U
Hsu et al. [26],; Taiwan	Crossover, 10 healthy subjects	(A) EA (2 Hz at BL15, 10 min, 𝑛=10); (B) sham EA (𝑛=10)	(1) LF norm; (2) HF norm; (3) LF/HF; (4) HRT	(1)–(4) A↓, B→: 𝑃<0.05	U, N, U, U, U
Hsu et al. [27],; Taiwan	Crossover, 10 healthy subjects	(A) AT (scalp-Sishencong, 10 min, 𝑛=10); (B) AT (Auricular-Shenmen, 10 min, 𝑛=10); (C) sham AT (𝑛=10)	(1) LF norm; (2) HF norm; (3) LF/HF; (4) HRT	(1)–(4) A↓, B↑, C→: 𝑃<0.05	U, N, U, U, U
Kim et al. [28],; South Korea	Crossover, 38 female subjects with regular menstrual cycle	(A) AT (LI4 and SP6, 15 min, 𝑛=38); (B) sham AT (minimal penetration on the same acupoints, 15 min, 𝑛=38); One-month washout between Tx	(1) LF; (2) HF; (3) LF/HF	(1) A↑, B↑: NS; (2) A↑, B↑: 𝑃<0.001 and <0.005; (3) A↓, B↓: 𝑃=0.001 and NS	U, N, Y, U, U
Streitberger et al. [16],; Germany	Crossover, 20 healthy subjects	(A) AT (LI4, 5 min and 15 sec manual stimulation, 𝑛=20); (B) sham AT (blunted placebo needle with no penetration on the same acupoints, 5 min and 15 sec manual stimulation, 𝑛=20)	(1) LF; (2) HF; (3) LF/HF	(1) and (2) A→, B→: NS; (3) A→, B→: NS, but A↑ during stimulation: NS	Y, N, Y, Y, U
Li et al. [29],; China	Parallel, 29 male healthy subjects (after 3 hr driving workout)	(A) AT (15 min, 𝑛=10); (B) sham AT (minimal penetration on nonacupuncture points, 𝑛=10); (C) Co (with driving, 15 min, 𝑛=9)	(1) LF/HF; (2) LF norm; (3) HF norm	(1)-(2) A↓, B→: 𝑃<0.05; (3) A↑, B→: 𝑃<0.05	U, N, Y, U, U
Chang et al. [30],; Taiwan	Parallel, 12 male healthy subjects with no neurological diseases	(A) AT (PC6, 3 sessions with one-week washout, 30 min, 𝑛=6); (B) sham AT (minimal penetration on nonacupuncture points, 3 sessions with one-week washout, 30 min, 𝑛=6)	(1) VLF; (2) LF; (3) HF; (4) LF/HF	NS for all cases	U, N, U, U, U
Kurono et al. [31],; Japan	Crossover, 14 male healthy subjects	(A) AT (epifascial stimulation at CV17 and CV16, needle inserted for 1s only, 𝑛=14); (B) sham AT (AT on nonacupoints, 𝑛=14)	(1) LF; (2) HF; (3) LF/HF	(1)-(2) A↑ in CV17, but not CV16; (3) NS for both CV17 and CV16	U, N, Y, U, U
Liu et al. [32],; USA	1st phase (acute); Crossover, 27 patients with functional dyspepsia (Rome II)	(A) TEA (25 Hz, PC6 and ST36, 30 min, 2 sessions, 𝑛=27); (B) Sham TEA (TEA was performed on sham acupoints, 30 min, 2 sessions, 𝑛=27); (C) Co (electrodes were placed in the acupoints but not turned on, 𝑛=27)	(1) HF; (2) LF/HF	(1) A↑ during 1st 30 min Tx, B→, C→: 𝑃=0.01; (2) A↓, B→, C→: 𝑃<0.05	Y, N, U, U, U
Liu et al. [32],; USA	2nd phase (chronic); Crossover, 27 patients with functional dyspepsia (Rome II)	(A) TEA for 2 weeks (twice daily, 30 min), 1 week-wash-out, sham TEA for 2 weeks; (B) viceversa	(1) HF; (2) LF/HF	(1) A↑ after 2 weeks, B→, C→: 𝑃=0.05; (2) A↓, B→, C→: 𝑃<0.05	Y, N, Y, Y, U
Shi et al. [33],; China	Crossover, 20 patients with coronary heart disease	(A) AT (30 min, 𝑛=20); (B) EA (30 min, 𝑛=20); (C) Co (no Tx, 𝑛=20)	(1) LF; (2) HF; (3) LF/HF	(1) A↓, B↓, C→: 𝑃<0.05; (2) NS for all groups; (3) A→, B↓, C→: 𝑃<0.05	U, N, U, U, U

AT: acupuncture treatment; EA: electroacupuncture; TEA: transcutaneous electroacupuncture; Co: control; Tx: treatment.
Risk of bias (1) sequence generation; (2) incomplete data; (3) patient-blinded; (4) assessor blinded; (5) allocation concealment performed.