Respicardia, the Minnetonka-based maker of a pacemaker-like device to treat central sleep apnea, has closed a fresh $58.5 million funding round on the heels of news that its Remede System was approved for sale in the United States.

The privately held company didn't disclose all of its investors, but an announcement Monday noted that the funding round was led by Massachusetts-based Zoll Medical, a medical device maker with a large portfolio of machines used in resuscitation and emergency medical care. (Zoll itself is owned by Japan-based conglomerate Asahi Kasei Group.)

All of Respicardia's major existing investors took part in Respicardia's latest funding round, the company said Monday.

"We believe the Remede System will soon become the treatment of choice for patients suffering from central sleep apnea," Respicardia Chief Executive Bonnie Labosky said in a statement. "Proceeds from the financing will be used to fund our U.S. commercialization efforts and support ongoing development of the system."

Respicardia's Remede device is an implantable neurostimulation system that applies mild current to the phrenic nerve during sleep to cause the diaphragm to expand and contract in a normal rhythm, restoring natural breathing. Unlike the more common obstructive sleep apnea, central sleep apnea is caused by the brain's inability to send appropriate signals to the muscles in the chest that control breathing. Without those signals, breathing can stop and start repeatedly through a night.

The U.S. Food and Drug Administration approved the Remede device for commercial sales in October after seeing the results of a company-sponsored randomized study of 151 patients.

In the treatment arm of the study, 51 percent of patients reported a significant decline in their symptoms after at least six months, compared to 11 percent of patients with the same improvements in the control group; the data were published in the Lancet in 2016.

Although central sleep apnea is a breathing disorder, doctors note that it often occurs among people with illnesses like chronic heart failure. The Mayo Clinic notes that irregular breathing may cut down on oxygen levels during sleep, and that repeated multiple episodes of low-blood-oxygen caused by central sleep apnea may worsen the prognosis and increase the risk of abnormal heart rhythms.

Several other more conservative treatments for sleep apnea exist, including losing weight and sleeping on your side, or using a system that applies air pressure through a mask, such as a bi-level positive airway pressure (BiPAP) machine. Doctors may also decrease a person's opioid medications, if they are taking them, and take steps to address any underlying heart disease, if that's related.