I've just checked it out (I work in health, and know a bit about the Healthcare Commission ratings) and they do exclude primary angioplasty. So it should be fair for London, unless the numbers getting thrombolysis are now so low that you start hitting the problems inherent in small numbers eg wide percentage changes over time periods. The information isn't easy to find, but if you go to: http://ratings2006.healthcarecommission.org.uk/Indicators_2006/Trust/Indicator/indicatorDescriptionShort.asp?indicatorId=2113 and then look at the fourth paragraph from the bottom (which starts 'the eligibility is defined...' you'll get it. This is my first comment, but I've been reading your blog for ages, and bought your book - I've really enjoyed both.