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 180° turns is cumbersome. The transseptal puncture permits a direct route to the LA via the intra-atrial 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.

HISTORY

The 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 applications—for example, catheter ablation of AF.

INDICATIONS

Access to the LA is needed for catheter ablation, percutaneous mitral valvuloplasty, and occasionally left heart catheterisation where an accurate …