Regulators have approved Boston Scientific Corp.'s newest implantable defibrillator that doesn't connect directly to the heart, one of several heart-device announcements in the past week involving companies with large presences in the state.

Fridley-based Medtronic Inc. announced two-year survival rates for its catheter-delivered aortic valve replacement system that it said could drive wider adoption of the technology in valve-surgery patients. And St. Jude Medical Inc. in Little Canada published a study that finds its tiny, one-of-a-kind device to remotely monitor blood pressure near the heart reduced mortality in heart-failure patients on drug therapy by more than half.

The companies' news was timed to coincide with the annual meeting of the American College of Cardiology, which drew an estimated 20,000 cardiology doctors, executives and investors to San Diego. "There was no shortage of positive catalysts across the cardiovascular landscape," J.P. Morgan analyst Michael Weinstein wrote in a note to investors.

Minnesota companies have long been a strong force in cardiology technology. On Monday, the state's industry lobbying group, LifeScience Alley, published an analysis showing Minnesota companies received about 800 approvals for cardiology devices in 2014, beating the second-highest state, California, which had about 500.

LifeScience Alley spokesman Ryan Baird acknowledged that the analysis gives Minnesota credit for Boston Scientific's heart devices, because much of its cardiology division is located in the state. The Massachusetts-based company employs more than 5,000 people in the Twin Cities.

The recent stream of cardiology-device news kicked off March 13, when the Food and Drug Administration issued a long-sought approval for Boston Scientific's Watchman device.

Invented by Minnesota doctors, the Watchman is supposed to cut the risk of blood clots leading to stroke in patients with quivering hearts by plugging a small space in the heart where clots form, called the left atrial appendage. Analysts predict the Watchman will become part of a $500 million annual market for left-atrial appendage plugs by 2019.

Four days later, the FDA announced a surprise early approval for Boston Scientific's Emblem device. The Emblem represents the company's second generation of implantable defibrillators that don't require wires attached directly to the heart in order to deliver powerful shocks to restart a heartbeat following sudden cardiac arrest.

The company says Emblem is an advance over traditional implantable defibrillators because the wires in the heart, called leads, "may be associated with infrequent but serious complications, including lead displacement, fracture and systemic blood infections, or the need for lead extraction, which may lead to hospital readmission, increased mortality and associated costs."

The new device will be rolled out gradually, as the company ramps up production and sells off inventory of an earlier iteration, the J.P. Morgan note said.

For Medtronic, meanwhile, much of the attention at the cardiology meeting focused on the latest survival statistics for CoreValve, its artificial heart valve that can be implanted through a tube inserted in the leg.

A company-funded study found that patients with severe obstruction of the aortic valve, which pumps oxygenated blood to the body, had a 22 percent mortality rate after two years with CoreValve. That compared to a 29 percent mortality rate for patients who got traditional surgery. The randomized study followed 747 patients at 45 hospitals for two years who had TAVR, or transcatheter aortic valve replacement therapy.

The difference in mortality was significant especially in light of the disease prevalence. Aortic stenosis affects 1.5 million Americans, 500,000 of whom have a severe form of the condition. Patients showing symptoms of the disease stand a good chance of dying within two years, doctors say. CoreValve is considered a reasonable alternative to traditional open-heart surgery for patients with severe aortic stenosis, but the company said the mortality data may lead to new guidelines that favor more TAVR procedures, especially as second- and third-generation devices are released.

"The discussion is likely to shift from, 'Should we use TAVR in intermediate-risk patients?' to 'Who shouldn't we use TAVR in?' " the J.P. Morgan report said. The TAVR market is expected to grow to $4 billion by 2020, although the Centers for Medicare and Medicaid Services is using an industry-run national registry to monitor which patients get the therapy.

Finally, St. Jude Medical announced positive results of a new analysis of existing data from a company-funded clinical trial. The new study found heart-failure patients whose hearts don't effectively pump oxygen-rich blood and who received "optimal" doses of drugs showed a 57 percent reduction in mortality after they got an implanted device called CardioMEMS to remotely monitor blood pressure between the heart and lungs. Patients with the device had a 43 percent reduction in hospitalizations, compared to a control group.

Last month, analysts with Needham & Co. called CardioMEMS "clearly the biggest potential growth driver" for St. Jude revenue in 2015, with $90 million in expected sales.

Joe Carlson • 612-673-4779

Twitter: @_JoeCarlson