Table 1 Baseline clinical characteristics of the study patients

Age (years)

55 (46 to 68)

74 (62 to 83)

<0.001

Male gender

90 (82)

177 (61)

<0.001

Pittsburgh overall performance category scale before index cardiac arrest

<0.001

   Category 1

109 (99)

216 (74)

   Category 2

1 (1)

62 (21)

   Category 3

0 (0)

12 (4)

   Category 4

0 (0)

0 (0)

Initial rhythm

<0.001

   Ventricular fibrillation

64 (58)

41 (14)

   Pulseless electrical activity

23 (21)

134 (46)

   Asystole

23 (21)

115 (40)

Bystander cardiopulmonary resuscitation

61 (55)

137 (47)

0.14

Time interval from collapse to start of cardiopulmonary resuscitation (minutes)

6 (1 to 10)

7 (1 to 14)

0.049

Time interval from collapse to return of spontaneous circulation (minutes)

35 (21 to 48)

43 (23 to 56)

<0.01

Admission after 2006

83 (75)

169 (58)

<0.01

Hypertension

44 (40)

85 (29)

0.04

Diabetes mellitus

29 (26)

47 (16)

0.02

Previous history of heart disease

42 (38)

63 (22)

<0.001

Previous history of myocardial infarction

18 (16)

15 (5)

<0.001

Previous history of chronic heart failure

16 (15)

27 (9)

0.13

Cause of cardiac arrest

   Acute coronary syndrome

46 (41)

56 (19)

   Old myocardial infarction

12 (11)

4 (1)

   Cardiomyopathy

13 (12)

8 (3)

   Spasm of coronary artery

8 (7)

2 (1)

   Others

27 (25)

72 (25)

   Unknown

4 (4)

148 (51)