** Shares of medical device maker Boston Scientific BSX.N tumble 10% to $82.65 premarket

** BSX expects 2026 adjusted EPS of $3.43 to $3.49, the midpoint of which is below analysts' average estimate of $3.47 - LSEG-compiled data

** Estimates net sales growth between 10.5% and 11.5% for 2026, slower than its 19.9% growth in 2025

** Electrophysiology franchise $(EP)$ sales of $890 million below Street estimates of $933 million, according to RBC analysts

** Sales of Watchman, co's stroke prevention device, came in 1% below consensus with U.S. market entirely responsible for the miss, at least three analysts said

** "Investors now have reason to question the trajectory of these two key growth drivers moving forward" - brokerage J.P. Morgan, referring to EP and Watchman businesses

** BSX reports Q4 EPS of 80 cents vs. average estimate of 78 cents

** Posts Q4 revenue of $5.29 billion vs. average estimate of $5.28 billion

** Shares fell ~7% in 2025

(Reporting by Sahil Pandey and Sriparna Roy)

((Sahil.Pandey@thomsonreuters.com))