Almost all accessory pathways can be located and ablated by RF techniques. Septal variants demand considerably more technical skill than do left lateral pathways. Catheter instability may make right-sided accessory pathways technically challenging. Even then it is probably preferable to deal with the accessory pathway by catheter techniques before surgery, which then can be restricted to nonarrhythmic goals. A rapid regular atrial rhythm due to intra-atrial reentry or to abnormal automaticity within atrial cells.
Digoxin toxicity is relatively rare because of more consistent formulations and better prescribing.
Because the arrhythmia source may be anywhere within the atria, the P-wave vector is inconsistent. Carotid sinus massage will slow or block atrioventricular nodal conduction, exposing the underlying atrial arrhythmia and suggesting that the atrioventricular node is not an integral part of the arrhythmia circuit. Atrial tachycardia with block has been considered almost diagnostic of digoxin toxicity, but, depending on the atrial arrhythmia rate and the conduction capacity of the atrioventricular node, any atrial tachycardia may be associated with block. Treatment Carotid sinus massage usually is ineffective. When the arrhythmia is secondary to digoxin toxicity, general supportive measures, electrolyte normalization, and administration, if available, of digoxin immune Fab are better than giving another antiarrhythmic drug.