Table 1. Sample demographics.

Sample demographics (n=55)	Young (< 50 y.o., n=27)	Old (> 50 y.o., n=28)
Gender, Male/Female	11 (40%)/16 (60%)	13 (46%)/15 (54%)
Age, year (mean ± s.e.m)	38.55±1.26	62.07±1.77
Body mass index (mean ± s.e.m)	33.31±2.00	30.00±1.32
Underlying diseases
Coronary artery disease	2 (7%)	7 (25%)
Hypertension	4 (15%)	14 (50%)
Hyperlipidemia	1 (4%)	10 (36%)
Diabetes mellitus	3 (11%)	7 (25%)
Atrial fibrillation	0	4 (14%)
Myocardial infarction	0	0
None of the above	6 (22%)	6 (21%)