Investigation of oxygen uptake during daily life activities in HF patients with and without LVADs.

In patients with terminal HF the gold standard for treatment is heart transplantation, though the Worldwide shortage of donor organs has led to increased use of implantable mechanical circulatory support devices. The treatment with implantable pumps in the form of a Continuous Flow Left Ventricular Assist Device (CF-LVAD, or simply LVAD) is extremely effective for a selected patient groups leading to significant improvement in survival and quality of life.

The device is a battery-powered flow pump that carries the blood from the left ventricle to the main artery, via a cannula, and thus relieves the failing left ventricle with up to 10 liters of blood per minute. An LVAD can be used both as lifelong support therapy (Destination Therapy, DT) or until transplantation can take place (Bridge therapy).

As patients today live for more than 10 years with the device as DT, the focus has shifted from mere survival to quality of life and physical ability.

In recent years, our research group showed that the pump speed and the patient's baseline heart rhythm (sinus rhythm vs atrial fibrillation) and reduced ability to regulate the intrinsic rhythm after implantation (chronotropic incompetence) are significant contributors to the reduced exercise capacity seen in this patient group.

Until now, studies have elucidated the work capacity of this patient group using a 6-minute walk test or bicycle test - none of these reflect how well the patient actually functions in his everyday life.

In this study, we will describe oxygen uptake related to specific daily activities (ADL-VO2) and compare these with the well-known maximum work capacity (percentage of expected oxygen uptake / pVO2) in this patient group.

LVADs:

Inclusion Criteria:

• Implanted durable left ventricular assist device
• Age>18yrs
• Signed informed consent

Exclusion Criteria:

• No consent
• Not able to complete VO2 test (physicians decision)