Introduction: T he reduced ejection fraction (EF) of left ventricle in patients with supported myocardial infarction (MI) is considered to have unfavorable pro-gnostic value for mortality, including sudden cardiac death (SCD), caused in most cases by ventricular ta-chyarrhythmias (VT).
Objective: We propose to evaluate the clinical signifi-cance and the prognostic value of EF in patients with ventricular tachycardias developed late after MI.
Methods: The study group included 90 patients, avera-ge age of 63.8 ± 1.1 years, 90% men, who survived a do-cumented VT episode, developed 6 weeks after an acu-te MI. Sustained ventricular tachycardia was documen-ted in 61.1% of patients, unsustained TV – in 25.6%, ventricular fibrillation – in 13.3% subjects. The time from MI to the VT episode was 47.1 ± 4.5 months. The EF was assessed by the transthoracic echocardiography and it’s the average value for all patients was 38.18% ± 1.17, a 1/3 of the subjects had an EF above 40%. The TV treatment included amiodarone and / or betablocker. The follow-up period was 20.2 ± 1.8 months, the en-dpoint being the patient’s death. In relation to left ven-tricle EF, the patients were divided into 2 groups: gr.I – patients with EF ≤35% (n=41) and gr. II – patients with EF >35% (n=49).
Results: The target groups did not differ according to the structure of the risk factors. Patients in gr. I was younger (p =0.05), more often they had previous an-terior MI (p≤0.01), they were rarely subjected to myo-cardial revascularization (p<0.05), more frequently had increased diameters and volume of left atrium and left ventricle (p<0.01) and the presence of left ventricle aneurysm (p<0.001). The two groups were comparable to the structure and timing of the post-infarction VT. Death rate during the surveillance was significantly hi-gher in gr. I compared to the gr. II (36.6% vs. 10.2%, p=0.003). In the reference period, the risk of SCD among those with EF ≤35% proved to be twice as high as those in gr. II (RR 2.18 [95% CI 1.17-2.51, p=0.02]). The Caplan – Meier curves demonstrated a significantly lower probability of survival in patients in the gr. I ver-sus gr. II (long – rank=6.62, p=0.01).
Conclusions: Despite the fact that EF below 35% is considered to be a risk determinant of sudden cardiac death caused by ventricular tachycardia in post-infarc-tion patients, in all investigated patients already having late ventricular tachyarrhythmias after IM the pro-portion of subjects with FE VS ≤35% and >35% were comparable. However, EF ≤35% in this patient patients is associated with a significantly higher risk of death, including sudden cardiac death.