Reversible impairment of left and right venticular systolic and diastolic function during short-lasting atrial fibrillation in patients with an implantable atrial defibrillator: A tissue Doppler imaging study

AF with a fast ventricular response may cause ventricular mechanical impair ment, though whether short-lasting AF with satisfactory rate control may af fect ventricular function is unknown. This study investigated if prompt car dioversion by an implantable atrial defibrillator (IAD) may prevent left (L V) and right ventricular (RV) systolic and diastolic dysfunction. Ten patie nts (mean age 61 +/- 9 years, 8 men) with paroxysmal AF without structural heart disease who received an IAD were studied by echocardiography and tiss ue Doppler imaging (TDI) for both ventricles. Measurements were made during baseline sinus rhythm and at I-minute, 20-minute, 4-hour, and 1-week postc ardioversion of an episode of spontaneous AF. The occurrence of AF and the ventricular rate were monitored at 2-hour intervals by the device. There we re 50 episodes of AF with a mean duration of 8.8 +/- 8.9 days (2 hours to 3 7 days). There tvas no difference in M-mode measured LV fractional shorteni ng and ejection fraction between baseline sinus rhythm and after cardiovers ion. However, the TDI derived myocardial systolic velocity (TDI-S) was sign ificantly lower at 1-minute postcardioversion and was normalized at 1 week in both LVs (baseline: 5.7 +/- 2.8, 2 minute: 4.2 +/- 1.0, 20 minutes: 4.3 +/- 0.9, 4 hours: 4.8 +/- 1.0, 1 week: 5.5 +/- 2.8 cm/s; P < 0.005 when com paring 1 minute and 20 minutes to baseline; P < 0.05 when comparing 4 hour to baseline) and RV (baseline: 10.4 +/- 2.2, 1 minute: 7.8 +/- 2.4, 20 minu tes: 8.2 +/- 1.2, 4 hours: 9.2 +/- 1.5, 1 week: 10.0 +/- 2.0 cm/s; P < 0.00 5 when comparing 1 minute, 20 minutes, and 4 hours to baseline). Fbr diasto lic function, transmitral Doppler study showed a decrease in early filling velocity at 1 minute (P < 0.05) and 20 minutes (P < 0.005), which was norma lized at 4 hours. There was no change in transtricuspid Doppler flow. Howev er, TDI derived myocardial early filling velocity was decreased in the LV ( baseline: 6.0 +/- 2.8, 1 minute: 5.4 +/- 2.3, 20 minutes: 5.4 +/- 2.1, 4 ho urs: 6.2 +/- 2.2, 1 week: 5.8 +/- 1.7 cm/s; P < 0.05 when comparing 3 minut e and 20 minutes to baseline) and RV (baseline: 8.9 +/- 3.5, 1 minute: 7.9 +/- 3.3, 20 minutes: 8.1 +/- 3.3, 4 hours: 8.5 +/- 2.9, 2 week: 8.4 +/- 3.5 cm/s; P < 0.05 when comparing 1 minute to baseline). AF of a longer durati on (> 48 hours) resulted in a more depressed TDI-S in LV (> 48 hours: 4.2 /- 1.0, 48 hours: 5.3 +/- 1.3 cm/s; P < 0.01). Shocks in sinus rhythm did n ot affect any of the above echocardiographic parameters. Therefore, despite adequate rate control, short-lasting AF impairs systolic and diastolic fun ction in both ventricles, which improves gradually after cardioversion. Ear ly restoration of sinus rhythm by an IAD minimizes ventricular dysfunction. TDI is a sensitive tool to assess early systolic and diastolic dysfunction .