Atrial enlargement as a consequence of atrial fibrillation.

Atrial Enlargement as a Consequence of Atrial FibrillationSanfilippo et all report that atrial enlargement can develop as a consequence of atrial fibrillation.This conclusion is based upon the determination by echocardiography of atrial volumes in a highly selected group of 15 patients without any 'confounding cause for atrial enlargement."Atrial dimensions were measured in various projections and volume calculated on the assumption that the atria were prolate ellipses.For the right atriunm, two of the dimensions employed to determine volume were regarded as equivalent!The problems inherent in these measurements and assumptions were described in a study reported in this journal long ago2 in which no relationship was found between left atrial volume as determined by angiocardiography and duration of atrial fibrillation.Sanfilippo et al' use their findings to support more aggressive attempts to eliminate atrial fibrillation.Yet in this "perfect" group of 15 patients with atrial fibrillation, electrical conversion failed in five, chemical conversion failed in an additional four, and no attempt at conversion was made in the remaining six and no reasons were given for not trying.Finally, endpoints3 for digoxin dosage are not mentioned in the 11 who were maintained on digoxin, or for control of the ventricular rate in the other four who were not.Atrial fibrillation is an unwanted arrhythmia, but its abolition to prevent atrial enlargement remains unproved.It is at once thought-provoking and sobering to learn from the work of Sanfil- ippo et all that restitution of sinus rhythm in these ideal patients was unsuccessful in every instance in which cardioversion was attempted, whether electrically or chemically.