Table 1.

Characteristics of cases and controls

	Cases		Controls
	n= 1010	%	n= 3030	%	OR	95% CI
Age (mean, SD)	67.60	12.40	67.60	12.37
Males	681	67.4	2043	67.4
No history of cardiovascular disease	436	43.2	1308	43.2
Past medical history:
Myocardial infarction	110	10.9	214	7.1	1.72*	1.32, 2.23
Angina	142	14.1	385	12.7	1.14	0.92, 1.44
Coronary revascularization	37	3.7	124	4.1	0.88	0.60, 1.30
Heart failure	101	10.0	113	3.7	3.52	2.57, 4.83
Hypertension	522	51.7	1606	53.0	0.76	0.56, 1.04
Low serum potassium	29	2.9	31	1.0	3.00	1.77, 5.09
Low serum calcium	6	0.6	9	0.3	2.00	0.71, 5.62
Low serum magnesium	0	0	1	0.03	–	–
Bradycardia	10	1.0	18	0.6	1.69	0.77, 3.70
Heart block	10	1.0	10	0.3	3.36	1.31, 8.62
Atrial fibrillation	74	7.3	125	4.1	1.98	1.44, 2.72
Epilepsy	56	5.5	54	1.8	3.20	2.19, 4.69
Syncope	20	2.0	31	1.0	2.05	1.13, 3.70
Dizziness	47	4.7	119	3.9	1.20	0.85, 1.71
Renal dysfunction	62	6.1	127	4.2	1.58	1.13, 2.20
Abnormal liver function	30	3.0	28	0.9	3.34	1.97, 5.66
High serum potassium	33	3.3	75	2.5	1.35	0.88, 2.07
Drug misuse	8	0.8	2	0.1	12.00	2.55, 56.50
Alcohol abuse	117	11.6	55	1.8	8.53	5.90, 12.32