St. Jude Medical Inc. STJ reported strong first-quarter 2016 earnings driven by a stellar performance by the Heart Failure (HF) segment. The company reported adjusted earnings of 90 cents, which beat the Zacks Consensus Estimate by a couple of cents.However, earnings decreased 3.2% year over year, primarily due to margin headwinds. At constant currency (cc), earnings increased 8.6% on a year-over-year basis.St. Jude Medical Inc. (STJ) EPS BNRI & Surprise Percent - Last 5 Quarters | FindTheCompanyTotal sales improved 8% to $1.45 billion, which beat the Zacks Consensus Estimate of $1.43 billion. At cc, total sales increased 11% on a year-over-year basis. On a comparable basis (including Thoratec’s result for both the periods) and adjusting for foreign currency, sales increased 2% on a year-over-year basis.International sales increased 8% at cc to $672 million, while U.S. sales grew 14% to $776 million.Segment ResultsEffective first-quarter 2016, St. Jude Medical started reporting product categories under five groups: Atrial Fibrillation (AF), Heart Failure (HF), Neuromodulation, traditional CRM and Cardiovascular.Atrial Fibrillation (AF) sales increased 9% year over year at cc to $291 million, driven by strong adoption of FlexAbility and TactiCath ablation catheters. International sales were up 6% to $162 million, while U.S. sales increased 12% to $129 million in the quarter.Heart Failure (HF) comprises cardiac resynchronization therapy products, ventricular assist devices and the CardioMEMS HF System products. Sales surged 51% at cc to $374 million. On a comparable basis and adjusting for foreign currency, sales increased 2% on a year-over-year basis.Neuromodulation sales jumped 10% year over year at cc to $116 million, driven by a 13% surge in U.S. sales and 5% increase in international sales.Robust performance for St. Jude Medical’s Burst technology in international markets and strong demand for Protege Spinal Cord Stimulation (SCS) System with upgradeable features in the U.S. drove quarterly results.Cardiovascular sales inched up 3% at cc to $301 million in the quarter. International sales climbed 5% to $180 million, while U.S. sales increased 1% to $121 million.Cardiac Rhythm Management (CRM) sales decreased 7% year over year to $366 million. U.S. sales fell 12% to $183 million while international sales decreased 2% to $183 million in the reported quarter.GuidanceFor the second quarter of 2016, St. Jude Medical expects sales to grow in the range of 1% to 3% at cc on a comparable basis. Earnings are forecasted in the range of $1.05 to $1.07 per share.For full-year 2016, St. Jude Medical reiterated sales growth forecast at 2% to 4% (at cc on a comparable basis). However, adjusted earnings are now projected in the range of $4.01 to $4.11 per share, up from the earlier guided range of $3.95 to $4.05.Zacks Rank & Key PicksCurrently, St. Jude Medical has a Zacks Rank #3 (Hold).Better-ranked stocks in the same sector are NuVasive NUVA, LeMaitre Vascular LMAT and Baxter International BAX. While NuVasive sports a Zacks Rank #1 (Strong Buy), both LeMaitre and Baxter have a Zacks Rank #2 (Buy).Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report ST JUDE MEDICAL (STJ): Free Stock Analysis Report BAXTER INTL (BAX): Free Stock Analysis Report LEMAITRE VASCLR (LMAT): Free Stock Analysis Report NUVASIVE INC (NUVA): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research