A recent poster at the Heart Rhythm Society meeting looked at the database of the Cardiovascular Health Study. This study began in 1989 and has followed more than 5000 patients aged 65 years or over. The researchers measured the number of atrial and ventricular ectopic beats in 1414 individuals randomly assigned to have 24h tapes fitted. Then they looked at the results of self-reported food frequency questionnaires and determined whether there was any association between the amount of caffeine consumption and the number of ectopic beats. In a nutshell, there was none and therefore in an asymptomatic group of older patients ectopic frequency is not linked to caffeine intake.
However these were asymptomatic people and perhaps in folk with palpitations caffeine withdrawal might just improve symptoms. If you search the medical literature for "caffeine" and "palpitations" you will find only a single study which has looked at this question. The researchers entered 13 patients in a randomised, double blind, 6 week intervention trial of dietary caffeine restriction, caffeinated coffee, and decaffeinated coffee measuring caffeine levels in the blood, a visual analogue score of palpitations and 24 hour ventricular premature beat frequency. Their interventions significantly reduced serum caffeine concentrations. The palpitation scores showed a small, but significant correlation with ventricular premature beat frequencies (r = 0.34) but there were no significant changes in palpitation scores or ventricular ectopic beat frequencies during the intervention weeks and no correlations between these variables and serum caffeine concentrations. The authors concluded that caffeine restriction has no role in the management of patients referred with symptomatic idiopathic ventricular premature beats.
So it seems at least as far as ventricular ectopic beats are concerned our advice to reduce caffeine consumption with the aim of improving symptoms is no founded on any evidence. For my own patients I usually say that if they want to give up tea or coffee for 2 weeks and review their symptoms that is fine. If the intervention subjectively makes a substantial improvement to how they feel then continue off the caffeine, otherwise go back to your normal regime. It is interesting that such commonly given advice is founded on such a weak evidence base.