Table 1.

Studies investigating the stiffness of the heart. For SWE and MRE, the printed Young's modulus represents the calculated values, using the shear modulus from the original studies and a Poisson's ratio of 0.4 [[15], [16], [17], [18], [19], [20], [21], [22]].

Method	Species	Chamber	Condition	Shear modulus	Young's modulus	N-numbers	Ref
Micropipette	Chick	heart tube	Embryonic (E4)		~ 1 kPa	4	[15]
		heart tube	Embryonic (E14)		~ 10 kPa	1
Micropipette	Rat	LV	Neonatal		6.8 ± 2.8 kPa	1	[16]
			Adult - healthy		25.6 ± 15.9 kPa	1
AFM	Rat	LV	Adult - healthy		18 ± 2 kPa	2	[17]
			Adult - MI		55 ± 15 kPa	2
Shear Wave	Sheep	Atrium	Adult - healthy	Diastole: 0.5 ± 0.1 kPa Systole: 6.0 ± 0.3 kPa	Diastole: 1.4 ± 0.3 kPa Systole: 16.8 ± 0.8 kPa	1	[18]
		RV		Diastole: 1.3 ± 0.3 kPa Systole:13.5 ± 9.1 kPa	Diastole: 3.6 ± 0.8 kPa Systole: 37.8 ± 25.5 kPa
		LV		Diastole: 1.3 ± 0.2 kPa Systole:12.5 ± 5.1 kPa	Diastole: 3.6 ± 0.6 kPa Systole: 35.0 ± 14.2 kPa
Magnetic Resonance Elastography	Pig	LV	Healthy	Diastole: 6.0 ± 1.8 kPa Systole: 9.3 ± 1.9 kPa	Diastole: 16.9 ± 5.0 kPa Systole: 26.2 ± 5.3 kPa	6	[19]
	Pig	LV	Juvenile – before surgery	Diastole: 3.9 ± 0.4 kPa Systole: 5.0 ± 0.7 kPa	Diastole: 10.8 ± 1.1 kPa Systole: 13.9 ± 2 kPa	21	[20]
			Juvenile – MI (21d)	Diastole: 5.5 ± 0.7 kPa Systole: 6.3 ± 1.0 kPa	Diastole: 15.3 ± 2 kPa Systole: 17.8 ± 2.8 kPa
	Human	LV	Adult - healthy	Systole: 5.64 ± 1 kPa	Systole: 15.8 ± 2.8 kPa	18 (13 Female and 5 Male; Mean age: 31 yrs.; range: 21–71 yrs)	[21]
			Adult, Obstractive HCM	Systole: 14.5 ± 2.2 kPa	Systole: 40.6 ± 6.2 kPa	2 Female; Ages: 26 and 43 yrs)
	Human	LV	Adult - healthy	early systolic phase: mean: 8.2 kPa; range: 7.2–11.8 kPa	early systolic phase: mean: 23.0 kPa; range: 20.2–33.0 kPa	11 (1 Female and 10 Male; Median age: 57; range: 52–84 yrs)	[22]
			Adult cardiac amyloid patients	early systolic phase: mean: 11.4 kPa: range: 9.2–15.7 kPa	early systolic phase: mean: 32.0 kPa; range 25.8–44.0 kPa	16 (3 Female and 13 Male; Median age 66.5; range: 50–85 yrs)