The left atrium (LA) is the most difficult cardiac chamber to access percutaneously. Although it can be reached via the left ventricle and mitral valve, manipulation of catheters that have made two 180u turns is cumbersome. The transseptal puncture permits a direct route to the LA via the intraatrial septum and systemic venous system. Previously the technique was used infrequently by cardiologists for mitral valvuloplasty and ablation in the left heart; however, the explosion of interest in catheter ablation of atrial fibrillation (AF) has meant the transseptal puncture is a routine skill of the modern cardiac electrophysiologist. This article looks at the practical aspects of this important procedure, particularly as applied to the cardiac electrophysiologist.
HISTORYThe transseptal puncture was developed by Ross, Braunwald and Morrow at the National Heart Institute (now the National Heart, Lung, and Blood Institute), Bethseda in the late 1950s to allow left heart catheterisation, principally for the evaluation of valvular heart disease. 1 Early problems were difficulty cannulating the left ventricle, injecting sufficient volume of contrast for imaging, and inadvertent aortic puncture. Important refinements were made to the needle and catheter such that Brockenbrough's description of the technique in 1962 differs little from that used now. 2 Mullins developed a combined catheter and dilator set designed precisely to fit over the Brockenbrough needle, which gives a smooth taper from the tip of the needle, over the dilator to the shaft of the sheath. 3 The terms Brockenbrough needle and Mullins sheath are often used by operators generically when referring to transseptal needles and sheaths, respectively; however, there is a range of equipment available from several manufacturers, often designed for specific applicationsfor example, catheter ablation of AF.
INDICATIONSAccess to the LA is needed for catheter ablation, percutaneous mitral valvuloplasty, and occasionally left heart catheterisation where an accurate haemodynamic assessment of the mitral valve is needed or where access to the left ventricle (LV) is denied by a prosthetic aortic valve. Catheter ablation accounts for the vast majority of these cases and in our institution transseptal puncture has been performed in 651 patients in the electrophysiology (EP) laboratory in the past 2 years (fig 1). Transseptal access is widely used for accessory pathway and ventricular tachycardia ablation; however, the huge increase in its use is due to AF cases. 4 Radiofrequency ablation of atrioventricular accessory pathways that span the mitral valve annulus can be performed via a transseptal puncture (anterogradely) or via the aorta and left ventricle (retrogradely). Observational studies that have compared the two routes have not shown any differences in safety or effectiveness. 5-7 Cardiologists, familiar with left heart catheterisation and coronary angiography, are comfortable using catheters in the aorta and left ventricle and therefore some electrophysiologists pre...