Previous studies show that sleep apnea increases the risk of sudden cardiac death in the population. In other words, sleep apnea represents a treatable condition which is also a potential risk factor of sudden cardiac death. Some previously non-randomized studies showed that in patients with HFrEF, both obstructive and central sleep apnea may increase risk of sudden cardiac arrhythmic death. Contrary to these observations, recently released preliminary data from the SERVE-HF trial indicate that in patients with HFrEF, treatment of central sleep apnea by adaptive servo-ventilation therapy increases cardiovascular mortality, and responsible mechanisms might include increased risk of sudden cardiac death.