The Heart network expanded in the North of England, Scotland and Wales on 6 May and the second quarter of 2014 included seven weeks of the additional newly rebranded stations.
Although Heart's reach was up year on year, it represented a decline of 0.6 per cent from Q1.
Global Radio's Capital network managed to maintain its audience and position as the second-biggest commercial brand during the quarter, with an average of 7.33 million listeners a week, down 0.7 per cent year on year.
Meanwhile, the next three biggest national stations – Classic FM, Kiss UK and Smooth – all added listeners in the last quarter.
Global Radio's Classic FM grew its reach 2.5 per cent, while stablemate Smooth is increased 6.8 per cent. Bauer Media-owned Kiss UK added 0.5 per cent to its reach during the same period, to 4.63 million.