Age (years)

74.9 9.7

78.5 8.2

70.0 9.3

<0.001

Male sex

87

(465)

83

(253)

93

(211)

<0.001

Clinical factors

Discussion

NYHA class

0.01

I

2

(10)

2

(6)

2

(4)

Our dataset describes several unique findings of critical

II

21

(110)

9

(28)

36

(82)

importance to patients, physicians, and payers. We have

III

63

(334)

67

(204)

58

(130)

IV

8

(42)

11

(34)

4

(8)

shown that in real-world clinical practice there is no long-

AF

32

(169)

38

(115)

24

(54)

0.001

term survival benefit associated with CRT-D compared

COPD

13

(67)

13

(40)

12

(27)

0.67

with CRT-P and that this is the case for patients with and

Diabetes mellitus

29

(154)

22

(88)

29

(65)

0.96

Heart rate (bpm)

65.7 15.7

65.2 17.5

66.3 13.2

0.43

without ischaemic heart disease. We have also demon-

QRS duration (ms)

152 26

154.2 27.8

150.0 24.4

0.07

strated in a subgroup analysis that there is no difference

Haemoglobin (g/dl)

13.1 4.60

12.8 1.8

13.5 6.7

0.07

in mode of death between those receiving CRT-D com-

Creatinine (mmol/l)

132 57

139.4 67.2

122.1 37.0

<0.001

Treatment factors

pared with CRT-P. Finally, our data serve to remind that

Elective procedure

73

(389)

71

(215)

77

(173)

0.13

even with optimal medical and device therapy the long-

CABG

38

(203)

33

(100)

46

(103)

0.003

PCI

19

(101)

15

(46)

24

(55)

0.008

term outcomes in unselected patients with heart failure

Valvular surgery

4

(23)

3

(10)

6

(13)

0.18

because of LVSD remain high.

ACEi/ARB use

86

(459)

83

(251)

92

(207)

0.004

Amiodarone use

9

(47)

5

(14)

15

(33)

<0.001

CRT alone is well proven to reduce mortality, hospital-

Anticoagulation use

33

(176)

34

(103)

32

(73)

0.63

b-blocker use

81

(433)

76

(232)

88

(200)

0.001

ization rate, and improve quality of life in patients with

Digoxin use

16

(87)

20

(61)

12

(26)

0.007

CHF and LVSD. Cardiac Resynchronization-Heart Fail-

Furosemide dose (mg)

61.9 53.2

64.4 55.6

62.0 53.2

0.23

ure analysed the effects of CRT-P versus OMT, demon-

Values are given as % of patients (number) or mean SD.

a P value between

strating a reduction in deaths related to pump

CRT-P versus CRT-DACEi/ARB, ACE inhibitor or angiotensin receptor blocker;

dysfunction,7 and when follow-up was extended, a signifi-

AF, atrial fibrillation; CABG, coronary artery bypass graft; COPD, chronic obstruc-

cant reduction in sudden death risk.15 Similar improve-

tive pulmonary disease; CRT-D, cardiac resynchronization therapy with defibrilla-

tor; CRT-P, cardiac resynchronization therapy with pacemaker; NYHA, New York

ments were seen in patients with LVSD but less severe

Heart Association; PCI, percutaneous coronary intervention.

symptoms in the Resynchronisation Reverses Remodel-

ling in Systolic Left Ventricular Dysfunction (REVERSE)

Fig. 2

trial study.16 The lower risk of sudden death and arrhyth-

100

mic events observed with CRT-P are likely to be the result

of an improvement in the CHF syndrome with reverse LV

CRT-P

remodelling and

improved neurohormonal

17

CRT-D

balance,

which may reduce the substrate for ventricular arrhyth-

80

mias.18 This was well demonstrated in the Multi-centre

Automatic Defibrillator Implantation Trial-CRT trial

(CRT-D versus ICD in mildly symptomatic patients with

(%)

60

LVSD) where, as LVEF improved following CRT, the risk

9

Survival

of ventricular arrhythmias significantly reduced. Reverse

remodelling is one of the most important benefits of CRT,

taking time to evolve.19 This might explain why CRT-D

40

might appear to have an early survival benefit in some

studies where the defibrillator might reduce death because

20

Table 3 Mode-specific mortality analyses

Adjusted HR = 1.1 (0.77-1.65)

Mode of death

Total cohort

CRT-P

CRT-D

P = 0.54

Cardiovascular

64.0% (57)

60.3% (38)

73.1% (19)

0

Progressive heart failure

39.3% (35)

38.1% (24)

42.3% (11)

Sudden

21.3% (19)

20.6% (13)

23.1% (6)

0

500

1000

1500

2000

Other

3.4% (3)

1.6% (1)

7.7% (2)

Follow-up (days)

Noncardiovascular

31.5% (28)

33.3% (21)

26.9% (7)

Unclassifiable

1.5% (4)

6.3% (4)

0 (0%)