* Tech results lift Nasdaq futures, Apple and Facebook rally
* Attention on Apple after announcing seven-for-one stock split
* U.S. shares of AstraZeneca up after results
* Futures up: Dow 50 pts, S&P 7.5 pts, Nasdaq 52 pts
By Ryan Vlastelica
NEW YORK, April 24 (Reuters) - U.S. stock index futures were higher on Thursday, with Nasdaq futures jumping more than 1 percent following a pair of blowout results from technology stalwarts Apple and Facebook.
* Apple Inc in particular will be in focus a day after the most valuable U.S. company by market capitalization posted revenue that far outpaced expectations, helped by strong iPhone sales.
* The company also approved another $30 billion stock buyback plan, raised its dividend and authorized a seven-for-one stock split, broadening the stock's appeal to individual investors. Shares rose 7.7 percent to $565 in heavy premarket trading.
* Social media giant Facebook Inc posted a 72 percent jump in first-quarter revenue, lifted by its mobile advertising business. Shares rose 5 percent to $64.41 before the bell. Twitter Inc rose 1.2 percent to $46.50.
* Apple and Facebook were the latest high-profile names to top expectations, a trend that has lifted the S&P 500 for six of the past seven sessions, though companies have largely been beating reduced forecasts. According to Thomson Reuters data, profits are seen rising 1.6 percent this quarter, down from the 6.5 percent growth rate estimated at the start of the year, according to Thomson Reuters data.
* S&P 500 futures rose 7.5 points and were above fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures added 50 points and Nasdaq 100 futures rose 52 points.
* Among other notable earnings on Thursday, drugmaker Eli Lilly & Co reported revenue that missed expectations, while insurer Aetna Inc's earnings topped forecast.
* Of the 141 companies in the S&P 500 that have posted results through Wednesday morning, 65.2 percent have topped expectations, above the long-term average of 63 percent. On the revenue side, 53.6 percent have exceeded forecasts, below the 61 percent long-term average.
* Tech will remain in view after the market closes, when Microsoft Corp and Amazon.com Inc are slated to post their results.
* U.S. shares of AstraZeneca rose 5.1 percent to $71.25 in premarket trading as the company highlighted progress with new cancer drugs, though it also reported core earnings that missed expectations. (Editing by Chizu Nomiyama)