Abstract Body (Do not enter title and authors here): Background
Although ample evidence exists for the causative role of frequent premature ventricular complexes (PVCs) in the development of cardiomyopathy, they may also be found in cardiomyopathy of other causes. We describe a case of improved PVC burden following implantation of a temporary mechanical circulatory support device in a patient with advanced heart failure.

Case Description
A 63-year-old male with familial non-ischemic cardiomyopathy and advanced heart failure on high dose milrinone (0.5 mg/kg/min) was admitted after outpatient right heart catheterization showed cardiogenic shock with high left ventricular (LV) filling pressures and cardiac index of 1.8 L/min/m2. On a previous admission, a high PVC burden had been noted but decreased markedly on outpatient ambulatory monitor placed on the day of discharge (Figure 1A). Telemetry was notable for a high PVC burden, predominated by bigeminy, with a predominant PVC morphology localized to the LV outflow tract (LVOT) (Figure 1B). The patient failed to improve with diuresis requiring axillary implantation of an Abiomed Impella 5.5 heart pump (Impella), with immediate improvement in cardiac output and pulmonary artery pressures. Preoperative transthoracic echocardiogram showed an LV end diastolic diameter (LVIDd) of 70mm compared to 65mm after Impella placement. Of significance, telemetry demonstrated a significantly lower PVC burden after Impella placement (Figure 1C).

Discussion
Although frequent PVCs can cause or be the result of cardiomyopathy, data on the effect of volume overload on PVC burden, as demonstrated in this case, are lacking. Left ventricular unloading with mechanical cardiac support led to a dramatic and immediate drop in PVC burden. We suggest that Impella placement relieved congestion and therefore LV stretch, reducing the excitability of the LVOT. This novel observation implies that PVC burden should be assessed when patients are euvolemic and warrants further exploration of the relationship between LV congestion and PVCs.