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Severe coronary artery spasm during radiofrequency ablation for atrial fibrillation

2014; Elsevier BV; Volume: 172; Issue: 3 Linguagem: Inglês

10.1016/j.ijcard.2014.01.090

1874-1754

Keiichi Hishikari, Taishi Kuwahara, Atsushi Takahashi, Mitsuaki Isobe,

Cardiac electrophysiology and arrhythmias

Pulmonary vein isolation has become a standard treatment strategy for atrial fibrillation (AF), [[1]Raviele A. Natale A. Calkins H. et al.Venice Chart international consensus document on atrial fibrillation ablation: 2011 update.J Cardiovasc Electrophysiol. 2012; 23: 890-923Crossref PubMed Scopus (76) Google Scholar] and is generally considered a safe procedure. However, some serious complications can occur [[2]Cappato R. Calkins H. Chen S.-A. et al.Prevalence and causes of fatal outcome in catheter ablation of atrial fibrillation.J Am Coll Cardiol. 2009; 53: 1798-1803Abstract Full Text Full Text PDF PubMed Scopus (467) Google Scholar]; therefore, attention needs to be paid to potential complications during AF ablation. ST-segment elevations have rarely been reported to occur during trans-septal catheterization or left atrial (LA) ablation, and most ST-segment elevations have been reported to be transient, with normal, subsequent coronary arteriography [[3]Le B.H. Black J.N. Huang S.K.S. Transient ST-segment elevation during transseptal catheterization for atrial fibrillation ablation.Tex Heart Inst J Tex Heart Inst St Lukes Episcop Hosp Tex Child Hosp. 2010; 37: 717-721PubMed Google Scholar]. We report a patient with a severe coronary artery spasm that was resistant to nitrate injection with hemodynamic collapse during LA ablation for AF. A 66-year-old man with drug-resistant, persistent AF was admitted to our institution for radiofrequency (RF) catheter ablation. After obtaining written informed consent, AF catheter ablation was performed. An irrigated ablation catheter, having a 3.5-mm tip (Navistar ThermoCool, Biosense Webster, Diamond Bar, CA, USA), was used, with a RF power of 25–30 W and a cut-off temperature of 45 °C, for 30–60 s at each site. The endpoint of the pulmonary vein isolation (PVI) was the point at which all pulmonary vein (PV) potentials were eliminated. After isolation of the left-sided PVs, we started RF application at the posteroinferior aspect of the right inferior PV. As was revealed retrospectively, 15 s after beginning the RF delivery, the ST-segment became slightly elevated in the inferior leads of the ECG. This slight change went unnoticed, and the RF delivery was continued for over 60 s at and adjacent to the first ablation point. The ST-segment continued to elevate (Fig. 1, left) until a marked ST-segment elevation was present, and a complete atrioventricular block (Fig. 1, right) developed in conjunction with severe systolic blood pressure hypotension (<50 mm Hg). We stopped RF delivery once the atrioventricular block was noticed. Subsequently, we performed coronary angiography and found that the left coronary artery (LCA) was normal and the right coronary artery (RCA) was totally occluded at its ostium (Fig. 2, left). Supportive therapy, such as noradrenalin injection and right ventricular pacing, was attempted, and nitrate was injected into the coronary artery but the total occlusion was not resolved. Although the coronary artery occlusion was refractory to repeated nitrate injection, the ST-segment elevation gradually improved and normalized 12 min after the start of the ST-segment elevation with normal coronary flow through the RCA (Fig. 2, right). We diagnosed this total occlusion of the coronary artery as a coronary artery spasm. Despite ST-segment normalization and the supportive therapy, the systolic blood pressure persisted at <80 mm Hg. Therefore, we decided to end the ablation session. The severe hypotension recovered the next morning, and echocardiography showed normal left ventricular wall motion after the procedure. A month after discharge, the patient was readmitted to for a provocative test with acetylcholine (Ach) in an attempt to confirm a diagnosis of a variant angina pectoris. Ach provocation (50 μg and 100 μg in the LCA, and 25 μg and 50 μg in the RCA) did not induce a spasm in either the LCA or RCA. LA catheter ablation can cause several serious complications, such as atrio-esophageal fistulas, cardiac tamponade, or strokes [[2]Cappato R. Calkins H. Chen S.-A. et al.Prevalence and causes of fatal outcome in catheter ablation of atrial fibrillation.J Am Coll Cardiol. 2009; 53: 1798-1803Abstract Full Text Full Text PDF PubMed Scopus (467) Google Scholar]. However, ST-segment elevations are rarely observed, and most involve transient ST-segment elevations and normal coronary arteries, as demonstrated by coronary angiography performed immediately after the ST-segment elevation [[3]Le B.H. Black J.N. Huang S.K.S. Transient ST-segment elevation during transseptal catheterization for atrial fibrillation ablation.Tex Heart Inst J Tex Heart Inst St Lukes Episcop Hosp Tex Child Hosp. 2010; 37: 717-721PubMed Google Scholar]. The present patient showed persistent ST-segment elevation due to a severe coronary artery spasm, revealed by subsequent coronary angiography, and the spasm was refractory to the repeated injection of nitrate, leading to hemodynamic collapse. Following an Ach provocation test to elucidate whether this patient had variant angina, we concluded that this patient demonstrated a very rare case of severe coronary artery spasm due to AF catheter ablation. The causes of ST-segment elevation other than a spasm may include an air embolism or a thrombotic occlusion [[4]Kuwahara T. Takahashi A. Takahashi Y. et al.Clinical characteristics of massive air embolism complicating left atrial ablation of atrial fibrillation: lessons from five cases.Eur Eur Pacing Arrhythm Card Electrophysiol J Work Groups Card Pacing Arrhythm Card Cell Electrophysiol Eur Soc Cardiol. 2012; 14: 204-208Google Scholar]. However, we did not exchange catheters before the ST-segment elevation, and the coronary angiography exhibited neither air emboli nor thrombi in the coronary artery. Therefore, a coronary artery spasm likely accounted for the ST-segment elevation in the present case. This patient did not have symptoms of angina, before or after the ablation procedure, and was not taking calcium antagonists or nitrates. Furthermore, a coronary artery spasm was not induced by the Ach provocative test. Okumura reported that the Ach provocation test has a sensitivity and specificity of 89–93% and 100%, respectively, for the induction of coronary artery spasm following intracoronary injection of Ach [[5]Okumura K. Yasue H. Matsuyama K. et al.Sensitivity and specificity of intracoronary injection of acetylcholine for the induction of coronary artery spasm.J Am Coll Cardiol. 1988; 12: 883-888Abstract Full Text PDF PubMed Scopus (248) Google Scholar]. The observed results indicated that this patient did not have variant angina, and that the coronary artery spasm that occurred during the LA catheter ablation was from the result of a specific mechanism associated with the LA catheter ablation itself. There are two possible mechanisms for a coronary artery spasm during AF catheter ablation. First, an autonomic nerve activity imbalance may have caused the spasm. The coronary artery spasm occurred during RF delivery to the posteroinferior aspect of the right inferior PV. Epicardial sites in this region are associated with a ganglionated plexus (GP), the so-called right lower GP. Endocardial RF ablation can affect the epicardial GP through a thermal injury that may cause an imbalance in autonomic nervous activity, frequently stimulating the parasympathetic nerve. Increased parasympathetic nerve activity could, in turn, induce a vasospasm of the coronary artery [[6]Yasue H. Horio Y. Nakamura N. et al.Induction of coronary artery spasm by acetylcholine in patients with variant angina: possible role of the parasympathetic nervous system in the pathogenesis of coronary artery spasm.Circulation. 1986; 74: 955-963Crossref PubMed Scopus (458) Google Scholar]. Alternatively, the RF energy may have caused direct thermal injury to the coronary artery. The delivery of RF energy adjacent to the coronary artery may cause a coronary artery spasm or occlusion [[7]Takahashi Y. Jais P. Hocini M. et al.Acute occlusion of the left circumflex coronary artery during mitral isthmus linear ablation.J Cardiovasc Electrophysiol. 2005; 16: 1104-1107Crossref PubMed Scopus (128) Google Scholar]. Since we did not deliver RF energy adjacent to the RCA, we speculate that the mechanism causing the severe coronary artery spasm was most probably an imbalance of autonomic nervous activity caused by RF thermal injury to the GP. We reported a rare case of severe coronary artery spasm occurring during AF catheter ablation, refractory to nitrate injection, and leading to hemodynamic collapse. Supportive therapy and repeated nitrate administration alleviated the spasm, which may have resulted from an autonomic nervous imbalance caused by the application of RF energy.