Stunning of the left atrium after pharmacological cardioversion of atrial fibrillation.
BACKGROUND
Stunning of the left atrium and atrial appendage is a well known but not fully clarified phenomenon observed during the cardioversion of atrial fibrillation regardless of the cardioversion method attempted.


OBJECTIVE
To assess the effects of propafenone and amiodarone on left atrium and left atrial appendage contractility.


METHODS
Forty patients with paroxysmal atrial fibrillation (20 females, 20 males), aged 60-83 (mean 72.0+/-10.1) years, were enrolled into the study. Half of these patients had sinus rhythm restored by the administration of oral propafenone (150-300 mg) and the remaining 20 patients were treated with intravenous amiodarone (150-450 mg). The control group consisted of 20 patients (10 females, 10 males) aged 52-78 (mean 61.2+/-9.3) years with sinus rhythm and no history of atrial fibrillation. All the patients had a transthoracic (TTE) and transesophageal (TEE) echocardiography performed while still in the AF, before drug administration and 1 hour after sinus rhythm restoration.


RESULTS
All haemodynamic parameters of the left atrium measured after the sinus rhythm restoration were significantly worse when compared with the control group. Left atrial fractional shortening and total atrial fraction were significantly lower after propafenone than amiodarone (8.6+/-3.6% vs 11.7+/-5.5%, p<0.05; and LA FC 16.2+/-5.3% vs 23.3 (+/-6.3)% respectively, p<0.05). Doppler echocardiographic parameters included in the analysis such as mitral flow and superior left pulmonary vein flow were significantly lower in the sinus rhythm restoration group than in the control group. Among them the end-diastolic mitral flow velocity amplitude and flow velocity integral as well as the maximum pulmonary retrograde velocity were significantly worse in the group treated with propafenone than in patients receiving amiodarone. All the atrial appendage Doppler velocity parameters were significantly reduced after the sinus rhythm restoration in both groups. In the patients treated with propafenone, values of these parameters were significantly decreased compared with the patients receiving amiodarone.


CONCLUSIONS
Successful pharmacological cardioversion of atrial fibrillation causes the left atrium and left atrial appendage contractility impairment similar to that observed with other methods of the sinus rhythm restoration. Following the AF cardioversion the level of left atrial stunning is higher in the patients treated with propafenone than in subjects receiving amiodarone.
Zapolski
Tomasz
T
Department of Invasive Cardiology, Medical Academy, Lublin, Poland. zapolia@wp.pl
Wysokiński
Andrzej
A
D000368:Aged; D000369:Aged, 80 and over; D000638:Amiodarone / Q000008:administration & dosage / Q000009:adverse effects*; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage / Q000009:adverse effects*; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging / Q000188:drug therapy*; D016279:Atrial Function, Left / Q000187:drug effects*; D001783:Blood Flow Velocity; D016009:Chi-Square Distribution; D017548:Echocardiography, Transesophageal / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000187:drug effects; D017682:Myocardial Stunning / Q000139:chemically induced*; D011405:Propafenone / Q000008:administration & dosage / Q000009:adverse effects*; D012849:Sinoatrial Node / Q000187:drug effects; D016896:Treatment Outcome
D000889:Anti-Arrhythmia Agents; D011405:Propafenone; D000638:Amiodarone