Prognostic significance of heart rate in hospitalized patients presenting with myocardial infarction

Table 1 Baseline characteristics (mean ± SD) n (%)

	HR< 70 (n = 480)	HR≥70 (n = 561)	P
Mean age	65.8 ± 11.9	67.3 ± 11.4	0.035
Women	128.0 (41.7)	179.0 (58.3)	0.037
Abdominal circumference (cm)	99.5 (11.9)	100.3 (13.0)	NS
Body mass index	28.1 (3.9)	28.1 (4.0)	NS
Hypertension	372.0 (77.5)	470.0 (83.8)	0.011
Diabetes mellitus	136.0 (28.3)	236.0 (42.1)	< 0.001
Dislipidemia	416.0 (86.7)	471.0 (84.0)	NS
Smokers	144.0 (30.3)	154.0 (27.5)	NS
History of heart disease	208.0 (43.3)	234.0 (41.7)	NS
History of CVA	37.0 (7.7)	57.0 (10.2)	NS
Peripheral Artery Disease	62.0 (12.9)	108.0 (19.3)	0.004
Previous heart failure	22.0 (4.6)	61.0 (10.9)	< 0.001
EF < 40%	32.0 (7.5)	83.0 (17.0)	< 0.001
Mean SBP (mmHg)	124.3 (18.5)	129.6 (22.4)	< 0.001
Mean DBP (mmHg)	71.8 (11.2)	74.2 (13.4)	NS
Mean HR (bpm)	60.3 (5.9)	80.6 (12.6)	< 0.001
Glucose (mg/dL)	116.7 (46.5)	131.4 (55.0)	< 0.001
Hemoglobin (g/L)	13.6 (1.6)	13.2 (1.9)	0.002
Total cholesterol (mg/dL)	180.6 (40.3)	180.9 (42.8)	0.015
LDL cholesterol (mg/dL)	109.9 (34.1)	109.5 (34.6)	NS
Creatinine (mg/dL)	1.03 ± 0.31	1.13 ± 0.82	NS
GFR (mL/min every 1.73 m2)	77.70 ± 23.80	75.30 ± 26.10	NS
ASA	409.0 (87.6)	446.0 (86.1)	NS
Diuretics	81.0 (16.9)	137.0 (62.8)	0.003
β-blockers	387.0 (80.6)	379.0 (67.6)	< 0.001
Calcium antagonists	72.0 (15.0)	119.0 (21.2)	0.010
ACE inhibitors	255.0 (53.1)	304.0 (54.2)	NS
Angiotensin II receptor blockers	51.0 (10.6)	80.0 (14.3)	NS
Statins	413.0 (86.0)	453.0 (80.7)	0.025
Coronary revascularization (PCI/thrombolysis)	294.0 (61.2)	287.0 (53.9)	0.001

HR: Heart rate; EF: Ejection fraction of the left ventricle; SBP: Systolic blood pressure; CVA: Cerebrovascular accident; DBP: Diastolic blood pressure; ASA: Acetylsalicylic acid; ACE: Angiotensin converting enzyme; GFR: Glomerular filtration rate; LDL: Low density lipoprotein cholesterol; SD: Standard deviation; PCI: Percutaneous coronary intervention.

Table 2 Outcomes n (%)

	HR < 70 (n = 480)	HR≥70 (n = 561)	P
Total deaths	13 (2.7)	45 (8.0)	< 0.001
Cardiovascular death	11 (2.3)	35 (6.2)	0.001
Non-cardiovascular death	2 (0.5)	10 (1.8)	0.035
Hospitalized for heart failure	22 (4.6)	63 (11.2)	< 0.001
Revascularization (PCI or surgical)	48 (10.0)	53 (9.4)	NS
Hospitalized for AMI	22 (4.6)	31 (5.5)	NS

HR: Heart rate; PCI: Percutaneous coronary intervention; AMI: Acute myocardial infarction.

Table 3 Multivariate analysis using Cox regression of overall mortality

Variable	Hazard ratio	95% CI	P
Heart rate ≥ 70 bpm	2.50	1.26-4.97	0.009
Peripheral artery disease	1.51	1.14-2.01	0.004
Revascularization at admission	0.53	0.29-0.97	0.040
EF < 40%	1.87	0.98-3.58	0.057
Age (per year)	1.08	1.03-1.12	< 0.001
Type 2 diabetes mellitus	1.80	1.01-3.22	0.047

EF: Ejection fraction of the left ventricle. The analysis includes: treatment with β-blockers, acetylsalicylic acid, angiotensin converting enzyme inhibitors, sex, history of ischemic heart disease and previous heart failure and all the variables in the table. C-Statistic: 0.61.