The non-invasive echocardiographic assessment of right ventricular myocardial work in a healthy population

Figures & data

Figure 1. (A) Tracing the tricuspid regurgitation velocity-time integral; (B) analysis of speckle tracking echocardiography-derived right ventricular global longitudinal strain; (C) evaluation of the event timings of the tricuspid valve and pulmonic valve in the parasternal short-axis views; (D) measurement of right ventricular myocardial work by incorporating pulmonary pressures, right ventricular strain and cardiac cycle timings.

Table 1. Clinical and echocardiographic characteristics of the study population.

Parameters	Total (n = 263)	Male (n = 100)	Female (n = 163)	p Value*
Age (years)	34 (29, 45)	34 (29, 43)	35 (29, 45)	.454
Height (cm)	163 (158, 170)	172 (169, 175)	159 (156, 163)	<.0001
Weight (kg)	58 (52, 67)	68 (62, 75)	54 (50, 59)	<.0001
BMI (kg/m²)	22.2 (20.1, 24.2)	23.0 (21.8, 25.1)	21.2 (19.2, 23.5)	<.0001
BSA (m²)	1.6 (1.5, 1.8)	1.8 (1.7, 1.9)	1.5 (1.5, 1.6)	<.0001
SBP (mmHg)	119 (108, 129)	126 (117, 131)	114 (104, 125)	<.0001
DBP (mmHg)	72 ± 10	74 ± 10	70 ± 10	.010
Heart rate (bpm)	66 (61, 74)	64 (58, 72)	68 (63, 75)	.001
PASP (mmHg)	22 (19, 25)	21 (19, 25)	22 (20, 25)	.115
PAMP (mmHg)	16 (14, 18)	16 (14, 18)	17 (15, 18)	.008
PADP (mmHg)	14 (12, 15)	13 (11, 15)	14 (12, 15)	.001
RV EDV (ml)	91 (83, 104)	108 (97, 121)	87 (78, 92)	<.0001
RV ESV (ml)	38 (34, 45)	49 (42, 55)	35 (31, 38)	<.0001
RV ejection fraction (%)	58 (56, 60)	55 (54, 56)	60 (58, 61)	<.0001
TAPSE (mm)	21 (19, 24)	22 (19, 24)	20 (18, 23)	.127
RV FAC (%)	47 ± 6	44 ± 4	49 ± 5	<.0001
RV S′ (cm/s)	13 (12, 15)	13 (12,14)	13 (12, 15)	.689
RV FWLS (%)	−23.1 ± 3.8	−22.0 ± 3.4	−23.8 ± 3.8	<.0001
RV GLS (%)	−20.1 ± 2.7	−19.3 ± 2.4	−20.7 ± 2.7	<.0001

Note: BMI: body mass index; BSA: body surface area; DBP: diastolic blood pressure; EDV: end-diastolic volume; ESV: end-systolic volume; FAC: fractional area change; RV: right ventricular; RV FWLS: RV free wall longitudinal strain; RV GLS: RV global longitudinal strain; PADP: pulmonary artery diastolic pressure; PAMP: pulmonary artery mean pressure; PASP: systolic pulmonary artery pressure; S′: tissue Doppler-derived tricuspid lateral annular systolic velocity; SBP: systolic blood pressure; TAPSE: tricuspid annular plane systolic excursion.

*p Value refers to gender differences.

Table 2. Parameters of right ventricular myocardial work.

	Total, mean ± SD or median (IQR)	Total, 95% limits of normality ± SE^a,b	Male, mean ± SD or median (IQR)	Male, 95% limits of normality ± SE^a,b	Female, mean ± SD or median (IQR)	Female, 95% limits of normality ± SE^a,b	p Value*
RVGWI (mmHg%)	306 (249, 351)	186 ± 5.0^b	270 (219, 326)	133 ± 15.4^b	323 (275, 375)	206 ± 8.1^b	<.0001
RVGCW (mmHg%)	354 (297, 408)	225 ± 5.9^b	319 (269, 375)	165 ± 18.2^b	372 (321, 433)	241 ± 12.6^b	<.0001
RVGWW (mmHg%)	21 (11, 33)	66 ± 3.3^a	22 (14, 32)	67 ± 6.6^a	20 (11, 35)	69 ± 3.1^a	.607
RVGWE (%)	93 (90, 96)	83 ± 0.5^b	92 (89, 95)	78 ± 1.8^b	94 (90, 96)	83 ± 0.7^b	.057

Note: IQR: interquartile range; RV: right ventricular; RVGCW: RV global constructive work; RVGWE: RV global work efficiency; RVGWI: RV global work index; RVGWW: RV global work waste; SD: standard deviation; SE: standard error.

^aHighest expected value.

^bLowest expected value.

*p Value refers to sex differences.

Figure 2. Individual values of right ventricular global work index (RVGWI), right ventricular global constructive work (RVGCW), right ventricular global wasted work (RVGWW) and right ventricular global work efficiency (RVGWE) according to sex and age categories. Horizontal lines represent median values or mean values. *p Value <.05 between sexes.

Table 3. Parameters of myocardial work and pulmonary artery pressure values according to sex and age.

	<30 years (n = 69)		30–40 years (n = 97)		40–50 years (n = 61)		≥50 years (n = 36)		p Value		Male		Female
	Male (n = 25), mean ± SD or median (IQR)	Female (n = 44), mean ± SD or median (IQR)	Male (n = 44), mean ± SD or median (IQR)	Female (n = 53), mean ± SD or median (IQR)	Male (n = 19), mean ± SD or median (IQR)	Female (n = 42), mean ± SD or median (IQR)	Male (n = 12), mean ± SD or median (IQR)	Female (n = 24), mean ± SD or median (IQR)	Male	Female	R	p Value	R	p Value
PASP (mmHg)	21 (19, 23)	21 (19, 24)	21 (19, 24)	21 (19, 23)	21 (18, 25)	23 (20, 25)	23 (20, 26)	25 (19, 27)^b	.334	.008	0.147	.144	0.247	.001
PADP (mmHg)	13 ± 2	14 ± 2	13 ± 3	13 ± 2	12 ± 2	14 ± 2*	14 ± 2	14 ± 3	.359	.225	0.063	.534	0.124	.115
RVGWI (mmHg%)	236 (205, 353)	322 (275, 376)*	275 (216, 323)	316 (282, 345)*	250 (212, 309)	336 (269, 381)*	314 (267, 346)	336 (258, 430)	.131	.563	0.132	.189	0.068	.387
RVGCW (mmHg%)	306 ± 75	371 ± 83*	326 ± 78	369 ± 74*	313 ± 53	395 ± 79*	377 ± 50^a,b,c	403 ± 100	.038	.189	0.185	.065	0.14	.074
RVGWW (mmHg%)	18 (10, 30)	16 (7, 24)	20 (13, 32)	18 (11, 31)	27 (18, 32)	30 (14, 46)^d	28 (25, 32)	27 (11, 50)^a	.109	<.0001	0.212	.034	0.334	<.0001
RVGWE (%)	93 (88, 96)	95 (91, 97)	93 (89, 96)	93 (91, 96)	91 (89, 95)	92 (88, 95)	92 (91, 93)	92 (89, 96)	.816	.053	−0.038	.704	−0.235	.003

Note: IQR: interquartile range; PADP: pulmonary artery diastolic pressure; PASP: systolic pulmonary artery pressure; RV: right ventricular; RVGCW: RV global constructive work; RVGWE: RV global work efficiency; RVGWI: RV global work index; RVGWW: RV global wasted work; SD: standard deviation.

^aSignificant difference between <30 years of age and ≥50 years of age.

^bSignificant difference between 30 to 40 years of age and ≥50 years of age.

^cSignificant difference between 40 to 50 years of age and ≥50 years of age.

^dSignificant difference between <30 years of age and 40 to 50 years of age.

*p Value <.05 vs. male.

Table 4. Univariable and multivariable analysis for RV myocardial work parameters.

	Univariable analysis		Multivariable analysis
	Coefficient	p Value	Standardised β-coefficient	p Value
RVGWI (mmHg%)
Age (years)	0.125	.043
Male (=1)	−0.331	<.0001	−0.242	<.0001
BMI (kg/m²)	−0.153	.013
BSA (m²)	−0.300	<.0001
Heart rate (bpm)	0.099	.109
PASP (mmHg)	0.716	<.0001	0.752	<.0001
PADP (mmHg)	0.478	<.0001
RVGCW (mmHg%)
Age (years)	0.187	.002
Male (=1)	−0.331	<.0001	−0.197	<.0001
BMI (kg/m²)	−0.122	.048
BSA (m²)	−0.308	<.0001
Heart rate (bpm)	0.081	.188
PASP (mmHg)	0.771	<.0001	0.735	<.0001
PADP (mmHg)	0.560	<.0001
RVGWW (mmHg%)
Age (years)	0.305	<.0001	0.215	.001
Male (=1)	0.035	.575
BMI (kg/m²)	0.207	.001	0.212	.014
BSA (m²)	0.030	.633
Heart rate (bpm)	−0.080	.193
PASP (mmHg)	0.219	<.0001
PADP (mmHg)	0.234	<.0001	0.184	.019
RVGWE (%)
Age (years)	−0.126	.041
Male (=1)	−0.111	.074
BMI (kg/m²)	−0.222	<.0001
BSA (m²)	−0.183	.003
Heart rate (bpm)	0.127	.039
PASP (mmHg)	0.089	.150	0.184	.027
PADP (mmHg)	0.021	.737

Note: BMI: body mass index; BSA: body surface area; PADP: pulmonary artery diastolic pressure; PASP: pulmonary systolic artery pressure; RV: right ventricular; RVGCW: RV global constructive work; RVGWE: RV global work efficiency; RVGWI: RV global work index; RVGWW: RV global wasted work.

Figure 3. The Bland–Altman analysis for assessing intra-observer variability of right ventricular global work index, right ventricular global constructive work, right ventricular global wasted work and right ventricular global work efficiency.

Figure 4. The Bland–Altman analysis for assessing inter-observer variability of right ventricular global work index, right ventricular global constructive work, right ventricular global wasted work and right ventricular global work efficiency.

Table 5. Intra- and inter-observer variability of RV myocardial work indices.

	Intra-observer variability			Inter-observer variability
	Bias	95% CI	ICC	Bias	95% CI	ICC
RVGWI (mmHg%)	1.3	−40.9; 43.4	0.96	−7.7	−41.7; 26.4	0.96
RVGCW (mmHg%)	−4.9	−48.5; 38.8	0.97	−2.6	−44.1; 38.9	0.94
RVGWW (mmHg%)	−2.4	−11.8; 7.0	0.91	0.1	−13.7; 13.9	0.89
RVGWE (%)	−0.6	−2.0; 3.1	0.92	−0.1	−4.1; 3.9	0.89

Note: CI: confidence interval; ICC: intraclass correlation coefficient; RV: right ventricular; RVGCW: RV global constructive work; RVGWE: RV global work efficiency; RVGWI: RV global work index; RVGWW: RV global wasted work.