Effect of High-Intensity Interval Training in De Novo Heart Transplant Recipients - 1 Year Follow Up (The HITTS Study)

Abstract

There is no consensus on how, when or at what intensity exercise should be performed and organized after heart transplantation (HTx). We have recently shown that high-intensity interval training (HIT) is safe, well tolerated and efficacious in maintenance HTx recipients. So far there have been no studies with HIT in de novo HTx patients. The major reason for this has been a concern for adverse effects due to a denervated heart. However, we and others have demonstrated that a partial reinnervation takes place with a near normalization of the heart rate (HR) response to exercise during the first year after HTx, possibly explaining the tolerability to this form of exercise in maintenance HTx patients. In contrast, the newly transplanted heart totally lacks innervation and consequently the heart rate response is greatly reduced. Heart failure patients are frequently deconditioned with low muscular capacity. Since muscular capacity is an important determinant of exercise capacity, our hypothesis is that HIT should be introduced as early as possible after surgery and will result in a clinically meaningful improvement in exercise capacity, muscular strength and quality of life (QoL). Thus, we have extended the HIT protocol also to de novo HTx patients (the HITTS study; High -intensity Interval Training in de novo Heart Transplant Recipients in Scandinavia).