Dr Dalby specialises in interventional cardiology (treating the heart using ‘keyhole’ methods under local anaesthetic through thin tubes) including coronary angioplasty and stent placement.

He is a co-founder of Harefield Hospital's distinguised 'primary angioplasty' program treating heart attack patients with emergency stent procedures. The hospital's primary angioplasty service has one of the fastest ‘door to procedure’ rates in the country - the rate of response plays a crucial role in the procedure's success. The program has now treated more than 10,000 patients.