Sinus Nodal Dysfunction After Left Atrial Flutter Ablation

Abstract

A 74-year-old man who had drug-refractory paroxysmal atrial flutter 2 years after circumferential pulmonary venous isolation was referred to our hospital. During repeated ablation, clinical arrhythmia was induced. Mapping of the left atrium revealed the entire tachycardia cycle length. Capturing fractionated bipolar electrograms at anterolateral left atrial (LA) wall demonstrated concealed entrainment with postpacing interval comparable with tachycardia cycle length. During linear ablation from mitral annulus along fractionated electrograms to the scar near left superior pulmonary vein using an irrigated tip catheter (power, 35 W; temperature, 40 o C), atrial flutter terminated, which was followed by sinus nodal (SN) arrest requiring urgent temporary pacing ( Figure 1). There was no recovery of SN function after 3 days, and a permanent pacemaker was implanted. A review of cardiac computed tomography (CT) before ablation revealed a small blood vessel originating from the left circumflex artery, running along the anterior LA wall to reach the cavoatrial junction of the right atrium, which was not seen in postablation CT (Figure 2). A 3-dimensional reconstruction image showed that this was a left-sided SN artery (Figures 3 and 4). DiscussionPersistent SN dysfunction has been reported in 7% of patients after ablation of atrial fibrillation and is thought to be the result of atrial remodeling and associated sinoatrial conduction abnormality.1 However, our patient had normal SN function before ablation as evidenced by excellent exercise tolerance and absence of bradycardia or long pause in Holter monitoring. Although vagal response during ablation near leftsided pulmonary vein is not uncommon, 2 and an unusually prolonged SN recovery time remained possible, taking persistent SN arrest and CT findings together, the mechanism was likely direct thermal injury to the SN artery. Although not well recognized, this is a potential complication during ablation at the left atrium because the prevalence of exclusively left-sided SN artery is up to 30% to 40%. The courses of left-sided SN artery were variable, with more than half of them running along the high anterior left atrium and the remainder either passing behind the LA appendage before overlying the roof or rarely running along the posterior left atrium to reach the right atrium. 3,4 The recognition of the course of SN artery can lead us to either avoid ablating at this location or limit energy delivery to prevent this complication. DisclosuresNone.

Acute and sub-acute sinus node dysfunction following pulmonary vein isolation: a case series

“…Acute/sub-acute persistent SND has only very recently been acknowledged as a potential complication of AF ablation, 5 despite previous isolated case reports 4 , 6 . Thermal injury to the SNA with subsequent ischaemia of the sinus node seems to have been at least partly implicated in all of our cases.…”

“…Whereas persistent SND requiring pacemaker implantation has been reported in 7% of patients following ablation of long-standing persistent AF, 11 significant bradyarrhythmia following electrical cardioversion of acute AF has been seen to occur in only 1% of patients 12 . Recently, Hai et al 4 have made the first report of acute SND following left atrial ablation. Although tachycardia-mediated suppression and remodelling of the sinus node may have contributed to their patient’s persistent sinus arrest, the most likely mechanism was direct thermal injury to the SNA 4 .…”

“…Recently, Hai et al 4 have made the first report of acute SND following left atrial ablation. Although tachycardia-mediated suppression and remodelling of the sinus node may have contributed to their patient’s persistent sinus arrest, the most likely mechanism was direct thermal injury to the SNA 4 . The authors highlighted the fact that the SNA is exclusively left-sided in up to 30–40% of cases, with more than half of these running along the high anterior left atrium and the remainder either passing behind the left atrial appendage before overlying the roof or rarely running along the posterior left atrium to reach the right atrium 13 , 14 …”

“…Vascular access complications constitute the majority, but AF ablation can also associate with cerebrovascular events, cardiac tamponade, phrenic nerve injury, pulmonary vein stenosis, or atrio-oesophageal fistula. Recently, some authors have proposed that ablation in the left atrium can also result in sinus node dysfunction (SND) requiring pacing 4–6 . However, to the best of our knowledge, none of the larger studies assessing complication rates of AF ablation have made a reference to this potential complication thus far 3 , 7 , 8 …”

The rationale for isolation of the left atrial pulmonary venous component to control atrial fibrillation: A review article

“…43 Sinoatrial node ischaemia has also been reported with the creation of roof lines. 44 However, its incidence has not been reported to date in prior clinical studies of ablation of the pulmonary venous component.…”