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In this evolving era of balloon mitral valvotomy (BMV), radiofrequency ablation (RF) of left-sided bypass tracts via catheter, and hemodynamic evaluation of aortic mechanical prostheses, there has been renewed interest in transseptal left heart catheterization (TSLHC). In the 3 years 1990-1994, 122 consecutive patients were referred for TSLHC to our institute (which lacks thoracic surgical facilities). 12 patients were excluded; 10 with a LA mass proven by transesophageal echocardiography (TEE), 1 with a vascularized thrombus in the circumflex coronary system and 1 with congenital interruption of the inferior vena cava with azygous continuity. In the remaining 110 cases TSLHC was performed for interventions in 90 cases (82%) of BMV, and for left-sided catheter radiofrequency (RF) ablation in 3 (3%). For diagnostic purposes it was performed in 17 (15%) cases for hemodynamic evaluation of mechanical aortic valve prostheses. Using the Brockenbrough needle, the adult Mullins sheath system (MSS) and single plane fluoroscopy, 100% technical success was achieved. Needle puncture was not needed in 30 (27%) due to direct crossing with the MSS through a stretched foramen ovale. In 2 we had to perform SVC dye injection for better interatrial septum localization. There were no complications when TSLHC was only used for diagnostic procedures. 1 patient had perforation of the LA due to right lower pulmonary vein laceration following septal dilatation. Following stabilization by immediate pericardiocentesis, the patient was transferred for open heart surgery. There were no great vessel perforations, systemic embolization or periprocedural deaths. TSLHC can be performed quite safely with single-plane fluoroscopy without an onsight surgical team, as with an experienced staff this procedure has very low morbidity and mortality.

Ablation by radiofrequency has recently come into use to treat cardiac arrhythmias, mostly supraventricular tachycardia. We describe 2 males aged 14 and 24, respectively, with idiopathic ventricular tachycardia. They underwent endocardial mapping and the exit points of the tachycardia were identified. In 1 of them tachycardia originated in the left ventricle, and the other in the outflow tract of the right ventricle. Radiofrequency ablation of the arrhythmia was successful in both.

Patients with supraventricular or ventricular tachyarrhythmias resistant to antiarrhythmic drugs are candidates for surgical ablation of the bundle of His, and of accessory pathways or ventricular or atrial foci responsible for the arrhythmia. During the past 6 years closed-chest catheter techniques have been devised that allow electrical shock ablation of the atrioventricular junction, accessory pathways, or foci responsible for arrhythmias. The promising results of these ablative procedures (especially of the atrioventricular junction and posteroseptal accessory pathways) justify their trial in suitable patients before cardiac electrosurgery.