Riera et al

(vector-electrocardiographic), and the possible anatomic causes, provoked by selective alcohol injection in the septal branch, for percutaneous treatment, of obstructive hypertrophic cardiomyopathy. Methods- Ten patients with a mean age of 52.7 years underwent percutaneous septal ablation (PTSA) from oc-tober 1998; all in functional class III/IV). Twelve-lead electrocardiogram was performed prior to and during PTSA, and later electrocardiogram and vectorcardio-gram according to Frank’s method. The patients were fol-lowed up for 32 months. Results- On electrocardiogram (ECG) prior to PTSA all patients had sinus rhythm and left atrial enlar-gement, 8 left ventricular hypertrophy of systolic pattern. On ECG immediately after PTSA, 8 had complete right bundle-branch block; 1 transient total atrioventricular block; 1 alternating transient bundle-branch block either right or hemiblock. On late ECG 8 had complete right bundle-branch block confirmed by vectorcardiogram, type 1 or Grishman. Conclusion- Septal fibrosis following alcohol injec-tion caused a predominance of complete right bundle-branch block, different from surgery of myotomy/myectomy. Key words: percutaneous septal ablation, obstructive hypertrophic cardiomyopathy, vector elec-trocardiographic alteration