Clinical features and prognosis of ventricular arrhythmias with preserved left ventricular ejection fraction: Multicenter registry from Tokyo CCU network
Authors: Ikenouchi T , Sasano T , Kobayashi Y , Tanno K , Fukamizu S , Murata H , Kataoka S , Ueno A , Higashikuni Y , Inagaki D , Furuya T , Goya M , Yamamoto T , Takayama M , Kosaka S 
Published: November 2023

Abstract

Background/Introduction
Ventricular arrhythmias (VAs) represent an important cause of morbidity and mortality, which are generally associated with reduced left ventricular ejection fraction (LVEF) [1]. However, VAs occasionally appear in patients with preserved LVEF, whose clinical features and outcomes remain limited.

Purpose
We assessed phenotypes and long-term prognosis of VAs with preserved LVEF by using the multicenter registry from Tokyo CCU network.

Methods
We enrolled 969 patients who admitted to hospital with ventricular fibrillation (VF) and/or sustained ventricular tachycardia (VT) (male 76.5%, mean age 65.6±16.3 years) from the Tokyo CCU Network database during 2018-2020. Exclusion criteria were missing data of echocardiography and VAs due to acute coronary syndrome, takotsubo cardiomyopathy, and acute myocarditis. Patients were divided into two groups according to their LVEF over (pEF group) and under 50% (rEF group). The primary outcome was 1-year mortality and secondary composite outcome included total death, stroke, and rehospitalization at 1-year. We also analyzed the risk factors of mortality in pEF group.

Results
The pEF group consisted of 419 (43%) patients (Figure), and they demonstrated younger age (pEF 63.8±18.1 vs rEF 67.1±14.7, p&lt;0.001) and lower percentage of male (68.7% vs 82.4%, p&lt;0.001), cardiomyopathy (59.9% vs 85.1%, p&lt;0.001), history of heart failure admission (9.0% vs 33.1%, p&lt;0.01), and hemodialysis (2.4% vs 6.3%, p&lt;0.001) compared to those in rEF group. Prevalence of VT (76.6% vs 68.3%, p=0.005) and bradyarrhythmia (10.9% vs 4.9%, p&lt;0.001) as an initial rhythm at admission, history of hypertensive heart disease (HHD) (18.6% vs 10.4%, p&lt;0.001), vasospastic angina (3.8% vs 0.4%, p&lt;0.001), and inherited arrhythmia (1.0% vs 0%, p=0.035) were higher in pEF group. The major heart disease in pEF group were HHD (18.6%), ischemic cardiomyopathy (ICM) (16.2%), and hypertrophic cardiomyopathy (HCM) (7.2%). Kaplan-Meier estimates revealed that the patients in pEF group had significantly lower rate of 1-year mortality (pEF 7.8% vs rEF 22.2%, p&lt;0.001) and composite outcome (18.7% vs 28.6%, p&lt;0.001) compared to those of rEF group (Figure). Multivariable analysis demonstrated that age (HR 1.036, 95% CI 1.00-1.07), hemoglobin (HR 0.81, 95% CI 0.66-0.99), hemodialysis (HR 6.83, 95% CI 1.21-38.6), and VF rhythm at admission (HR 4.03, 95% CI 1.51-10.7) were the predictors of mortality in pEF group, while each major cardiomyopathy including HHD, ICM, HCM showed no association to mortality (all &gt;0.1).

Conclusions
Patients with VAs and preserved LVEF showed younger age with less comorbidities including cardiomyopathy and better clinical outcomes compared to those with reduced LVEF. Aging, anemia, and hemodialysis might be the independent risk factors of mortality in VAs and preserved LVEF, while the types of major background heart disease might have little effect on life expectancy.Graphical abstracts