Shares in Carrefour will be eyed after the world's second-largest retailer said it would boost capital expenditure this year as it seeks to cement a revival of its European hypermarkets and expand in the key emerging market of Brazil.
Financial spread-betters expected Britain's FTSE 100 to open 11 to 12 points lower, or down 0.2 percent, Germany's DAX to open 8 to 13 points higher, or up 0.1 percent, and France's CAC 40 to open 3 to 5 points higher, or up 0.1 percent.
The ECB, which starts its quantitative easing, or bond-buying, programme worth more than 1 trillion euros this month, is expected to detail the plan later in the day following its policy meeting.
The bank is set to keep rates on hold, likely lift growth forecasts to reflect a string of positive data surprises, but cut inflation projections as it incorporates the full effect of a dramatic oil price fall.
The pharmacy sector will be in the spotlight after drug maker AbbVie Inc said it will buy Pharmacyclics Inc, the maker of blockbuster cancer drug Imbruvica, for about $21 billion to broaden its oncology drugs pipeline.