Arrhythmias (IV). Clinical approach to atrial tachycardia and atrial flutter from an understanding of the mechanisms. Electrophysiology based on anatomy.

In 2009, 2343 catheter ablation procedures were performed in Spain for focal atrial tachycardia or atrial flutter (typical and atypical), with a yearly growth rate of 8%, indicating the clinical importance of these arrhythmias. The classic categorization of atrial tachycardia and atrial flutter based on rate and morphological criteria has become almost irrelevant at a time when clinical electrophysiology may lead to curative intervention based on a definition of the mechanism, making it necessary to bring laboratory experience closer to clinical practice. In this review we outline our present understanding of atrial tachycardia mechanisms, both focal and macroreentrant, and attempt to establish the conceptual links with classic concepts that may help the clinician to make a differential diagnosis and establish therapeutic indications, including that of an electrophysiologic study.

A simple pacing method to diagnose postero-anterior (clockwise) cavo-tricuspid isthmus block after radiofrequency ablation.

Aims: Bidirectional block of the cavo-tricuspid isthmus (CTI) is a widely accepted endpoint for typical atrial flutter ablation, but its evaluation may be difficult, especially in the postero-anterior (clockwise) direction. The main goal was to evaluate pacing at the septal edge of the ablation line as an indicator of clockwise CTI block and as a predictor for flutter recurrence.

Methods And Results: In 94 patients undergoing flutter ablation, CTI block in the antero-posterior (counterclockwise) direction was determined by differential pacing from several levels of the anterior right atrial (RA).

[The superior vena cava as a site of ectopic foci in atrial fibrillation].

Radiofrequency catheter ablation of ectopic foci that trigger atrial fibrillation has been established as a curative method for patients with symptomatic paroxysmal atrial fibrillation. Although the majority of these foci are located in and around the pulmonary veins, other less common locations have been identified. Recognition that foci can lie outside the pulmonary veins is important for ensuring therapeutic success.

[Atrial flutter: an update].

Invasive electrophysiologic studies have changed the clinical outlook for patients with atrial flutter. Recognition of the reentrant circuit responsible for typical atrial flutter has led to the development of catheter ablation techniques that can prevent recurrence in >90% of cases. In addition, general understanding of atrial tachycardias has changed radically, such that ECG-based classifications are now obsolete.

[Cardiac resynchronization in heart failure: well-established therapy or new approach with unanswered questions?].

Biventricular pacing is a new development in the treatment of ventricular failure associated with intraventricular conduction delays, and the term ventricular resynchronization has been coined, implying for many authors that synchronous right and left ventricular activation and contraction are the goal of therapy. However, there is ample evidence that isolated left ventricular stimulation may be at least as efficacious as biventricular stimulation, and the mechanisms of functional improvement remain speculative. The role of mitral regurgitation and its modification with resynchronization has not been fully evaluated.

[Electrophysiological and clinical characterization of left atrial macroreentrant tachycardia].

Background And Objective: We are reporting the characteristics of 9 patients with left atrial macroreentrant tachycardia, an arrhythmia not well studied in man.

Patients And Method: Mean age was 60 years and 7 were men. Tachycardia was spontaneous in 6 and induced in 3.