Indian Pacing Electrophysiol. J.

ISSN 0972-6292


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Indian Pacing Electrophysiol. J. 2013;13(1):1-3           Editorial

Left Ventricular Outflow Tract Tachycardias

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Johnson Francis, MD, DM, FCSI, FACC, FRCP Edin

Senior Consultant Interventional Cardiologist, Baby Memorial Hospital, Calicut, Kerala, India

Address for Correspondence: Dr. Johnson Francis, MD, DM, FCSI, FACC, FRCP Edin, Senior Consultant Interventional Cardiologist, Baby Memorial Hospital, Calicut, Kerala, India. E-mail: pulikkottil2002/at/hotmail.com

Key words: Left Ventricular Outflow Tract Tachycardias, Radiofrequency Catheter Ablation
           
Left ventricular outflow tract tachycardia (LVOT-VT) is an uncommon type of idiopathic left ventricular tachycardia (ILVT) thought to be due to cyclic adenosine mono phosphate (c-AMP) mediated triggered activity. The arrhythmia can be terminated pharmacologically with calcium channel blockers or beta-blockers [1]. LVOT-VT can arise above or below the coronary cusps and the former variety can also be called as aortic cusp VT. An S wave in lead I and a precordial R wave transition at V1 or V2 is common to both varieties of LVOT-VT. Absence of S wave in V5 or V6 may suggest supra cuspal origin while an Rs pattern in V5 or V6 may indicate an infracuspal origin [2].

Yet another classification of LVOT-VT [3] was into VT originating from aortic cusps, from aortomitral continuity, anterior site around the mitral annulus and the epicardium. In case of aortic cusps, VT usually arises only form the right and left coronary cusps due to the extension of ventricular muscle fibers into their bases, while it seldom arises from the non-coronary cusp, which lacks these fibers and is composed of fibrous tissue.

Tachycardiomyopathy, though much more common with supraventricular arrhythmias, has also been described with ventricular arrhythmias. Most of these reports were in case of right ventricular out flow tract tachycardias (RVOT-VT). In this issue of the journal, Mora G et al [4] describe the reversal of tachycardiomyopathy after successful ablation of LVOT-VT. In their patient, left ventricular ejection fraction improved from 35% before ablation to 70% at one month after ablation. There was also a reversal of left ventricular dilatation, with absence of symptoms.

Various approaches have been described for the ablation of LVOT-VT. Shimoike E, et al [5] mapped the origin of two cases to the posterior LVOT corresponding to the aortomitral continuity or left fibrous trigone and successfully ablated them. Successful termination of the tachycardia was obtained by basal septal ablation in one case by Chiladakis JA et al [6]. Trans coronary cusp RF ablation has been achieved in case of LVOT-VT arising near the left coronary sinus [7]. A minimally invasive surgical approach may be useful in LVOT-VT with an epicardial origin when an endocardial approach fails [8]. Such VTs can be mapped through the anterior interventricular vein and ablation through the vein can also be successful [9]. Some of the VTs originating near the anterior epicardial veins can also be ablated form the left coronary sinus or nearby LV endocardium [10].

Advanced technologies like intracardiac echocardiography [11], three dimensional non contact mapping [12] and magnetic electroanatomic mapping [1,13] have all been used in the successful mapping and ablation of LVOT-VT. Ablation of LVOT-VT may not be always successful and free of complications. Campos B et al had 56% success rate in their 16 cases of VT originating from the left sinus of Valsalva near the anterior epicardial veins [10]. Turkoglu C and colleagues [14] reported chronic total occlusion of left circumflex coronary artery after RF ablation of LVOT-VT.

References

1. Dixit S, Marchlinski FE.Clinical characteristics and catheter ablation of left ventricular outflow tract tachycardia.Curr Cardiol Rep. 2001;3:305-13.

2. Hachiya H, Aonuma K, Yamauchi Y, Harada T, Igawa M, Nogami A, Iesaka Y, Hiroe M, Marumo F.Electrocardiographic characteristics of left ventricular outflow tract tachycardia. Pacing Clin Electrophysiol. 2000;23:1930-4.

3. Kumagai K, Fukuda, Wakayama Y, et al. Electrocardiographic characteristics of the variants of idiopathic left ventricular out flow tract ventricular tachyarrhythmias. J Cardiovasc Electrophysiol 2008; 19: 495-501.

4. Guillermo Mora, Nohra Romero, van Rendon. Tachycardiomyopathy a Rare Manifestation of Left Ventricular Outflow Tract Tachycardia. Treatment with Radiofrequency Catheter Ablation. Indian Pacing Electrophysiol. J. 2013;13:38-42

5. Shimoike E, Ohba Y, Yanagi N, Hiramatsu SI, Ueda N, Maruyama T, Kaji Y, Kanaya S, Fujino T, Niho Y.Radiofrequency catheter ablation of left ventricular outflow tract tachycardia: report of two cases. J Cardiovasc Electrophysiol. 1998;9:196-202.

6. Chiladakis JA, Vassilikos V, Maounis T, Cokkinos DV, Manolis AS.Unusual features of right and left idiopathic ventricular tachycardia abolished by radiofrequency catheter ablation. Pacing Clin Electrophysiol. 1998;21:1831-4.

7. Shimoike E, Ohnishi Y, Ueda N, Maruyama T, Kaji Y.Radiofrequency catheter ablation of left ventricular outflow tract tachycardia from the coronary cusp: a new approach to the tachycardia focus. J Cardiovasc Electrophysiol. 1999;10:1005-9.

8. Frey B, Kreiner G, Fritsch S, Veit F, Gössinger HD.Successful treatment of idiopathic left ventricular outflow tract tachycardia by catheter ablation or minimally invasive surgical cryoablation. Pacing Clin Electrophysiol. 2000;23:870-6.

9. Hirasawa Y, Miyauchi Y, Iwasaki YK, Kobayashi Y.Successful radiofrequency catheter ablation of epicardial left ventricular outflow tract tachycardia from the anterior interventricular coronary vein. J Cardiovasc Electrophysiol. 2005;16:1378-80.

10. Campos B, Park KM, Tschabrunn CM, Frankel DS, Park RE, Gerstenfeld EP, Mountantonakis SE, Garcia FC, Dixit S, Tzou WS, Hutchinson MD, Lin D, Riley MP, Cooper JM, Bala R, Callans DJ, Marchlinski FE.Ablation of ventricular arrhythmias arising near the anterior epicardial veins from the left sinus of Valsalva region: ECG features, anatomic distance, and outcome. Heart Rhythm. 2012;9:865-73.

11. Lamberti F, Calo' L, Pandozi C, Castro A, Loricchio ML, Boggi A, Toscano S, Ricci R, Drago F, Santini M.Radiofrequency catheter ablation of idiopathic left ventricular outflow tract tachycardia: utility of intracardiac echocardiography. J Cardiovasc Electrophysiol. 2001;12:529-35.

12. Storey J, Iwasa A, Feld GK. Left ventricular outflow tract tachycardia originating from the right coronary cusp: identification of location of origin by endocardial noncontact activation mapping from the right ventricular outflow tract. J Cardiovasc Electrophysiol. 2002;13:1050-3.

13. Rausch P, Manfai B, Varady E, Simor T.Radiofrequency catheter ablation of left ventricular outflow tract tachycardia with the assistance of the CartoSound system. Europace. 2009;11:1248-9.

14. Turkoglu C, Aliyev F, Arat-Ozkan A, Gurmen T.Chronic total occlusion of left circumflex artery after radiofrequency ablation of left ventricular outflow tract tachycardia. Europace. 2010;12:443-4.

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