P6357Left ventricular unloading leads to heart rhythm stabilization in cardiogenic shock - Results from the Dresden Impella Registry
Authors: Mierke J , Loehn T , Ende G , Akram Y , Jahn S , Schweigler T , Quick S , Pfluecke C , Jellinghaus S , Linke A , Ibrahim K 
Published: October 2019

Abstract

Background
Cardiogenic shock (CS) is often associated with severe heart rhythm disturbances (SHRD). Percutaneous left ventricular assist devices (pLVAD) can actively unload the left ventricle (LV) using a micro-axial pump and resulting in a decreased end-diastolic pressure and wall tension. These parameters are suspected to induce and maintain rhythmological instability.

Purpose
In the current study, we firstly describe the termination of SHRD immediately (less than 5 minutes) after LV-unloading in CS patients with previous unsuccessful antiarrhythmic treatment.

Methods
The Dresden Impella Registry is an ongoing single center registry. Since 2014, a total of 97 patients were included. Each of whom had received a micro-axial heart pump in refractory CS supplying a circulatory support of 3.5 l/min. We investigated the subgroup of patients which initially exhibited SHRD like ventricular tachycardia or ventricular fibrillation, and showed an immediately stabilization of heart rhythm directly after insertion of pLVAD (HRS). This subgroup was compared with the other patients of the registry (NHRS). Therefore, clinical laboratory and hemodynamic parameters were measured and analyzed.

Results
In 19 patients of the registry a HRS was observed. Among these patients, a CPR before pLVAD was performed in 89.5% with a mean duration of 30.7min, whereby 52.6% sustained an in-hospital cardiac arrest and 36.9% an out-of-hospital cardiac arrest respectively. In the NHRS subgroup (n=78), a CPR was performed less frequently (39.7%; p<0.001) with shorter mean duration (19.5min; p=0.016) and a lower out-of-hospital ratio (12.8%; p=0.014). The comparison of hemodynamic parameters between the HRS and NHRS cohort showed no difference in mean arterial pressure, heart rate, left ventricular ejection fraction (LVEF), and serum lactate.
The mortality showed no differences between the HRS and NHRS cohort at 30 days (68.4% vs. 58.1%; p=0.413) and 90 days (78.9% vs. 66.7%; p=0.306), despite a more frequent and longer CPR with a higher ratio of out-of-hospital cardiac arrests among the HRS patients. There was also no difference in mortality between patients, who received an in-hospital CPR. However, HRS patients with in-hospital CPR showed a significantly lower serum lactate and NA dosage compared to the NHRS cohort (Figure A & B). Furthermore, NA recovery, defined as 50% decrease as compared to the initial NA dosage, occurred more frequently in the HRS group (HRS 42.9% vs. NHRS 7.1%; p=0.049). The LVEF nearly double in the HRS subgroup after LV-unloading, whereas it did not change in the NHRS subgroup (relative LVEF increase: HRS 95% vs. NHRS 15%).
Figure A & B

Conclusion
The termination of SHRD due to LV-unloading occurred in around 20% of CS patients in Dresden Impella Registry and was associated with a lower serum lactate and NA dosage as well as an improved LVEF among patients with in-hospital CPR.

Acknowledgement/Funding
None