Hospitals are penalized when they readmit too many heart-failure patients, which is why Medtronic PLC is touting new data showing a Minnesota-made implantable device can reduce the odds of rehospitalizations by almost 60 percent.

It's the kind of economic analysis that is becoming more common as medical device companies attempt to show that their gadgets not only save lives, but do so in the most cost-effective way.

In this case, the data pertain to a treatment called cardiac resynchronization therapy, or CRT, which uses an implanted pacemaker or defibrillator to deliver tiny shocks that force the heart's left and right ventricles to beat in sync.

Out-of-sync heart beats can decrease the heart's efficiency and cut blood flow. In severely affected patients, it may be corrected by stimulating both the left and right ventricles in unison — known as biventricular pacing. Yet some patients with CRT devices may only need stimulation in the left ventricle some of the time.

The Medtronic AdaptivCRT algorithm is a new program included in the company's line of Viva pacemakers and defibrillators that senses when the heart needs only left-ventricular pacing and switches to that mode, among other adjustments it can make.

Doing so reduced patients' odds of readmission dramatically. Medtronic researchers found 36 percent of their severely sick heart-failure patients using traditionally calibrated CRT systems were readmitted within 30 days, compared to 19 percent of patients whose device had the new algorithm.

Dr. David Steinhaus, medical director for Medtronic's cardiac rhythm and heart-failure management business, said it's the only system of its kind on the market today. That explains why it helped Medtronic grab 8 percent market share for initial implants after it was released last year as part of a wider update of the company's CRT devices.

"Usually market share doesn't change a whole lot in this space very quickly, but this really moved the market very quickly," Steinhaus said of the device, which is made in Mounds View and assembled in Puerto Rico.

Medtronic doesn't break out its CRT sales in financial reports. The devices are included in its cardiac-rhythm and heart-failure division, the company's largest, with $5.2 billion in sales for the year ended in April and 8 percent growth on a constant-currency basis.

The company announced last year that the new algorithm seemed to increase the percentage of patients who responded well to CRT and reduce the number of hospitalizations for heart failure.

But hospitals that implant such devices are increasingly concerned about patients who return to the hospital unexpectedly. The latest data show that 22.7 percent of Medicare heart-failure patients are readmitted within 30 days, which is hard on patients and uses up health care resources.

Medicare can dock hospitals' overall reimbursements by up to 3 percent per year if their overall readmission rates are too high, and heart failure readmissions are one of the five specific measures used to gauge that rate.

"It is upsetting to the patient, it is upsetting to the family," said Kathy Cummings, a registered nurse and project manager with Minnesota's Institute for Clinical Systems Improvement. "But we also today have to look at cost. Each readmission costs between $10,000 and $15,000. And if we can prevent that, we are lowering cost for the whole health care system."

Joe Carlson • 612-673-4779

Twitter: @_JoeCarlson