Table 1.

Biophysical comparison of a healthy and a dilated human heart.

Level	Parameters	Healthy heart	Dilated heart
Organ	Morphology	Left ventricle slightly larger than the right ventricle	Enlarged and weakened left ventricle [13]
		Diameter between 39 and 59 mm [12]	Diameter larger than 69 mm [12]
	Function	Full ejection fraction around 100 mL per beat [30]	Ejection fraction reduced of 45% [6]
			Not enough oxygen provided
	Remodeling	Reversible remodeling with endurance [15] or pregnancy	Irreversible remodeling: increased ECM deposition, fibrosis, inflammation [15]
Tissue	Stiffness	From 7 kPa to 15 kPa [31]	Increased due to fibrosis and collagen deposition [32]
			Decreased elasticity [33]
	Inflammation	Inflammation is due to infection, oxidative stress or hypertension [18,34]	Robust proinflammatory response following cellular damages [18]
			Recruitment of immune cells
	ECM	Fibers of collagen I and III (ratio 7:1) [35]	Overproduction of fibronectin and collagen [14] (especially I and VI [33]) Fibrosis occupy 20% of the volume [36]
		Proteoglycans	Loss of CM alignment
		Anisotropy to allow CM alignment
	Capillary density	2439 ± 59 capillaries per mm [2,37]	1245 ± 345 capillaries per mm2
			Increased intercapillary distance [38]
			Shorter and smaller coronary arteries [22]
	Cell composition	Cardiomyocytes (18%), endothelial cells (24%) and mesenchymal cells (58%) [19] CM fill 75% of the volume [20]	Loss of 10% of CM [36] Decreased cell density
Cardiomyocytes (CM)	Sarcomeric passive tension	Ratio 30/70 between the two isoforms of titin	Reduced ratio 50/50 when titin is mutated [39]
			Faster relaxation kinetics [25]
			Myofibrils stiffness decreased by 26% [23]
	Contractile function	ECM stiffness for best force contraction generation [26]	Decreased force capacity depending on the mutation [23]
	Ionic exchanges	Calcium concentration is high during systole and low during diastole (from 1 μM to 100 nM) [40]	Increased calcium sensitivity, enhances the contraction rate [23] Tissue acidification alters electrical conduction [29]
	Cell metabolism	Adult cells consume fatty acids [41]	Metabolism switch to glucose consumption [27,42]
	Cell density & morphology	108 cells/cm3	Loss of cardiomyocytes [17] Visible remodeling scars [43] Cell hypertrophy around 2 fold [36]
		High length/width ratio (7:1)