P1082The history of syncope in heart failure. Mortality increases - but not in all

Abstract

Introduction: History of syncope (HoS) is discussed to be a risk factor for sudden death in patients (pts) with advanced heart failure (HF). It is known that among HF pts with a HoS left-ventricular (LV) systolic dysfunction is more prevalent than in those without HoS. However little is known about the role of syncopes in pts with HF with preserved EF (HFpEF). Our target was the difference between the HF entities and the prognostic effect in a large pooled patient cohort. Method(s): We pooled data from 4659 subjects from several heart failure trials of the competence network HF. Excluding insufficient follow-up details we evaluated 4256 pts (1576 HFrEF, 584 HFpEF). HFrEF was defined as LVEF<35% plus at least one symptom due to HF, HFpEF as LVEF>50% plus E/e>15 plus at least one symptom due to HF. We evaluated baseline characteristics including age, sex, NYHA class, medication, co-morbidities, device therapies, lab work and echo parameters plus HoS with a logistic regression model. Result(s): 13.2% of the pts reported a HoS. We learned that pts with HoS took more often distinct medication (diuretics, antiarrhythmics and glycosides), were more often female, older, hypotensive, anemic and suffered from both CKD and structural heart disease. NYHA classes were positive correlated with syncopes. Our data confirms that the HoS was more prevalent in HFrEF pts than in controls (p<0.001) and in HFpEF pts (p=0.029). In contrast, in HFpEF pts. it was not different from healthy controls (p<0.125). After adjustment for age, gender, NYHA Class, medication, device therapy, history of CAD or AMI, present anemia and depression, our results remained consistent and showed that HoS is independent from these confounders. Pts with HoS at baseline were more likely to suffer 1.from syncope during follow-up regardless of HF entity (noHF [p=0.004], HFrEF [p<0.001], HFpEF [p<0.001]), 2. from a worse overall (p<0.001) and 3. a worse hospitalization-free survival (p<0.001) after 96 months. Discussion(s): Taking into account the Iower prevalence of HoS in HFpEF pts the explanation for syncopes in HF pts remains unclear. With stroke volume being impaired in both HFrEF and HFpEF chronic borderline cardiac output is unlikely to describe the mechanism of action. It has been shown that a Iow LVEF is associated with arrhythmia and sudden cardiac death. This explains the high numbers of ICDs, RV and LV pacemakers and antiarrhythmic drugs in our HFrEF data. The idea of arrhythmic episodes leading to hemodynamic instability among the HFrEF population as an explanation for both HoS and worse outcome is confronted with the statistical adjustment for ICD therapy in these pts which did not reduce the effect of HoS. In conclusion, the pathophysiology remains undefined and further assessment of HoS as a highly promising tool in the setting of HF in prospective trials is required. (Figure Presented).