dual-chamber pacing has an additive effect on the reduction of outflow gradients. Balram Bhargava, MD, DM,. RajivAgarwal, MD, DM,. Upendra Kaul, MD, DM,.
CORRESPONDENCE The First Septal Artery Supplies the Atrioventricular Node To the editor: A recent article' reported a case of hypertrophic obstructive cardiomyopathy in which the patient un-
derwent a transcatheter alcohol ablation of the 1st septal artery. The patient had a successful recovery of his intraventricular pressure gradient, and he returned to his usual activities some weeks later. However, after the procedure, he developed a persistent atrioventricular block that required the implantation of a dual-chamber permanent pacemaker. There is anatomical evidence that the 1st septal artery supplies the right bundle branch, the His bundle itself, and the atrioventricular node.2 In 1976, Christides3 demonstrated, through coronary injection with epoxy resin, some cases of anastomosis between the rami septi fibrosi (the atrioventricular
node artery) and the septal artery. More recently, by means of gross and microscopic dissection, we have objectively shown that the 1st septal artery supplies the atrioventricular node (Fig. 1).4 As a consequence of this anatomical connection, we believe that any kind of procedure involving this vessel should be performed with extreme caution. Gustavo Abuin, MD,
Alejandro Nieponice, MD, Cardiac Anatomy Research Laboratory, Division ofAnatomy, Buenos Aires University Medical School, Buenos Aires, Argentina
References 1.
Bhargava B, Agarwal R, Kaul U, Manchanda SC, Wasir HS. Transcatheter alcohol ablation of the septum in hypertrophic cardiomyopathy. Tex Heart Inst J 1998;25:156-7.
Fig. 1 The 1st septal artery (large arrows) supplying the atrioventricular node. AD = anterior descending artery; AV = atrioventricular node; His = bundle of His
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Abuin G. Bypass a la primera septal, justificaci6n anat6mica y angiografica. Presented at 27th Congress, Asociaci6n Rioplatense de Anatomia. Rosario, Argentina. 4 Oct 1990. 3. Christids C, Cabrol C. Anatomie des arteres coronaires du coeur. Laboratoires Besins-Iscovesco. Paris 1976;57-96. 4. Abuin G, Nieponice A. New findings on the origin of the blood supply to the atrioventricular node: clinical and surgical significance. Tex Heart Inst J 1998;25:113-7. 2.
ablation. Perhaps this treatment in combination with dual-chamber pacing has an additive effect on the reduction of outflow gradients. Balram Bhargava, MD, DM, Rajiv Agarwal, MD, DM, Upendra Kaul, MD, DM, Subbash C. Manchanda, MD, DM, Harbans S. Wasir, MD, DM, Department of Cardiology, Cardiothoracic Sciences Centre, All India Institute ofMedical Sciences, New Delhi, India
The above letter was referred to Dr. Bhargava and colleagues, who reply in this manner:
We thank Drs. Abuin and Nieponice for their interest in our images (and related report) pertaining to transcatheter alcohol ablation of the septum in hypertrophic cardiomyopathy, and we congratulate them on their new findings on the origin of the blood supply to the atrioventricular node.' We agree with the authors that procedures performed on the 1st septal artery should be performed with extreme caution, and indeed we ourselves have emphasized the same.2 However, on the basis of clinical experience, the commonest arrhythmia reported in association with septal alcohol injection is right bundle-branch block, which occurs in 52% to 85% of patients so treated.3'4 Complete heart block has been reported to occur in 60% to 65% of patients, with only 20% of those requiring permanent pacemaker implantation (when the condition persisted for more than 2 weeks).3 Kuhn and associates5 have not reported any conduction defects in 35 minutes of ischemia induced without alcohol injection, which may be an important method of screening patients suitable for this procedure. However, Seggewiss and coworkers6 report that the predictability of the acute hemodynamic results of this transitory occlusion is not very high, due to the presence of several small septal branches. Therefore, complete heart block in septal alcohol ablation is unpredictable. Presumably, the procedure should be avoided in cases of pre-existing left bundle-branch block. Further, complete heart block has to be interpreted as a consequence of alcohol
Texas Heart Institute Journal
References 1. 2.
3. 4.
5.
Abuin G, Nieponice A. New findings on the origin of the blood supply to the atrioventricular node: clinical and surgical significance. Tex Heart Inst J 1998;25:113-7. Bhargava B, Agarwal R, Behl VK, Reddy KS, Kaul U, Manchanda SC. Alcohol therapy for hypertrophic cardiomyopathy: is it time to toast? Circulation 1998;97:2096-7. Bhargava B, Narang R, Agarwal R, Behl VK, Manchanda SC. Conduction blocks following transcatheter septal ablation for hypertrophic cardiomyopathy. Eur Heart J 1997;18:2011-2. Knight C, Kurbaan AS, Seggewiss H, Henein M, Gunning M, Harrington D, et al. Nonsurgical septal reduction for hypertrophic obstructive cardiomyopathy: outcome in the first series of patients. Circulation 1997;95:2075-81. Kuhn H, Gietzen F, Leuner C, Gerenkamp T. Induction of subaortic septal ischaemia to reduce obstruction in hypertrophic obstructive cardiomyopathy. Studies to develop a new catheter-based concept of treatment. Eur Heart J
1997;18:846-51. 6. Seggewiss H, Gleichmann U, Faber L, Fassbender D, Schmidt HK, Strick S. Percutaneous transluminal septal myocardial ablation in hypertrophic obstructive cardiomyopathy: acute results and 3-month follow-up in 25 patients. J Am Coll Cardiol 1998;31(2):252-8.
Letters to the Editor should be no longer than 2 doublespaced typeuritten pages and should contain no more than 4 references. They should be signed, with the expectation that the letters will be published if appropriate. The right to edit all correspondence in accordance withJoumal style is reserved by the editors.
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