W.S.J.ONG1, K.K.I.CHUNG1, C.J.LIM1
Tan Tock Seng Hospital1
Cigarette smoking is a well-known risk factor for increased cardiovascular morbidity and mortality, by causing inflammation, thrombosis, oxidation of low-density lipoprotein cholesterol, and cardiac fibrosis. Cardiac fibrosis is suggested as a fundamental factor for predicting cardiovascular morbidity and mortality in heart failure patients. Little data is available on the effect of smoking on non-ischemic cardiomyopathy (NICMP). We hypothesize that smoking has an adverse effect on prognosis of patients with NICMP.
This study included 447 patients with heart failure and reduced left ventricular ejection fraction (LVEF<40%) due to NICMP, all had coronary angiogram to exclude significant coronary artery disease (>70% stenosis). Mean follow-up duration 6.34 ± 4.16 years. Composite endpoints include death, ventricular arrhythmia or hospitalisations for heart failure. Data were analysed using STATA version 16.0. Cox regression was used to explore the relationships between smoking and composite endpoints. Statistical significance denoted as p<0.05.
Mean age 63.07 ± 14.19 years, male patients 314 (72%). Mean LVEF 22.89 ± 8.50%. Patients with diabetes mellitus 38%, hypertension 76%, atrial fibrillation 38%, stroke 9%. LDL 2.78 ± 1.04 mmol/l, HbA1c 6.56 ± 1.62%. Patients taking ivabradine 9%, beta-blocker 88%, angiotensin inhibitors/angiotensin receptor blockers 66%, sacubitril/valsartan 26%, spironolactone 57%, SGLT-2 inhibitor 9%. 40 patients (9%) received device therapy (AICD and CRTD), 19% secondary prevention, 81% primary prevention. Smoking (100 cigarette pack year) increased the hazards for the composite endpoint by 2.39 [HR (95% CI): 1.074, 5.325; p = 0.033].
Smoking increases the hazards for composite endpoints in patients with NICMP and smoking cessation is recommended.