53 Coarse Fibrillatory Waves in Atrial Fibrillation Predict Success of Electrical Cardioversion

Abstract

<h3>Introduction</h3> Electrical cardioversion (ECV) is an established therapy for the management of persistent atrial fibrillation (AF). Although ECV is initially successful, recurrence rates of 70–80% have been reported at follow-up at 1 year.¹ Fibrillatory waves (Fw) can often been seen on the surface ECG in AF and can be characterised simply and reliably based on their amplitude.² Amplitudes of ≥0.1 mV are classified as coarse, whilst &lt;0.1 mV are classified as fine (Figure 1). Recent invasive human electrophysiological studies have suggested that AF initiates via organised mechanisms.³ We hypothesised that coarse Fw reflected more ‘early’ organised AF and were therefore a predictor of maintenance of sinus rhythm (SR) after ECV. <h3>Methods</h3> We conducted a single centre retrospective observation study by obtaining records of 138 consecutive ECVs. Two cardiologists independently analysed the pre-ECV ECG and classified fine (fFw) or coarse (cFw) F-waves in leads II and V1 using callipers. Follow up was by analysing the 4-week post ECV ECG to assess rhythm. Demographics, drug treatments and echocardiography parameters were analysed as well. <h3>Results</h3> From the 138 consecutive ECVs, 8 were excluded due to incomplete datasets, 15 due to atrial flutter being the starting rhythm and 3 due to non-concurrent classification of the Fw by the two cardiologists. Out of the 112 pre-ECV ECGs, 32% (36/112) had cFw in V1, lead II or both. After ECV, SR was immediately achieved in 95% (106/112) of patients. Overall, of those that were successful, 46% (49/106) were back in AF at the 4-week clinic visit. All patients with cFw had successful initial ECV. At follow-up, 75% (27/36) of patients with cFw on pre-ECV remained in SR compared with 43% (30/70) of patients with fFw who had a successful initial ECV (p = 0.001, Fisher’s exact test). The cFw and fFw groups were of the similar mean age (70.5 vs. 71.2, p = 0.72). Amiodarone use was similar between groups (8% vs. 17%, p = 0.26) as was left atrial size (4.2 vs. 4.4 cm, p = 0.3); left atrial volume (59 vs. 54 mls, p = 0.5) and indexed left atrial volume (41.8 vs. 39.0 mls/m², p = 0.34) (Table 1). <h3>Conclusion</h3> The presence of coarse Fw in V1, lead II or both resulted in a significantly higher ECV success rate at 4 weeks than fine Fw in both leads. This appeared to be independent of traditional factors thought to affect success. The presence of cFw may be a simple ECG based measure to refine the role of ECV in the treatment of patients with AF. <h3>References</h3> Lundström T, Rydén L. Chronic atrial fibrillation. Long-term results of direct current conversion. ActaMedScand.1988;223(1):53–59 Xi Q, Swiryn S. Atrial fibrillatory wave characteristics on surface electrogram. J Cardiovasc Electrophysiol. 2004;15(8):911–917 Schricker AA, Narayan SM. Human Atrial Fibrillation Initiates via Organized Rather Than Disorganized Mechanisms. Circ Arrhythm Electrophysiol. 2014;7(5):816–824