Medical device maker Boston Scientific Corp. reports its second-quarter earnings Tuesday after markets close.

WHAT TO WATCH FOR: Analysts and investors will continue to watch sales of the company's heart-pacing implants. Boston Scientific stumbled in March when it suspended sales of its two leading implantable heart defibrillators because it failed to notify regulators of changes in the way it makes the devices. Medical device manufacturers are required to notify federal health authorities within 10 days of making manufacturing changes to such devices.

Analysts estimate the company lost 3 percent of its market share to competitors Medtronic and St. Jude Medical during the month-long sales suspension. On Tuesday analysts will try to gauge whether the company is recovering that lost market share.

WHY IT MATTERS: Pacemakers and defibrillators, collectively termed "cardiac rhythm management" devices, are Boston Scientific's largest franchise. Sales of the devices fell 9 percent year-over-year to $538 million in the last quarter.

Sales of defibrillators have been flat in recent years due to a combination of safety concerns, market saturation and price competition. Wedbush analyst Philip Nalbone says Boston Scientific and its two main competitors "will be slugging it out for share in a declining market" going forward.

Amidst this pressure, Chief Executive Ray Elliot, has tried to reposition Boston Scientific by reducing financial risk, cutting 10 percent of the work force and restructuring management.

Oppenheimer analyst Steven Lichtman writes in a recent move that "the shift in focus is certainly the right move long term. However, we are still in the earlier innings of this major refocus, and realignment and disruptions are possible along the way."

WHAT'S EXPECTED: Analysts polled by Thomson Reuters expect Boston Scientific to report earnings of 3 cents per share on revenue of $1.9 billion.

LAST YEAR'S QUARTER: Boston Scientific reported earnings per share of 10 cents and revenue of $2 billion a year ago.