Atrial tachycardia

Atrial tachycardia is a type of heart rhythm problem in which the heart's electrical impulse comes from an ectopic pacemaker (that is, an abnormally located cardiac pacemaker) in the upper chambers (atria) of the heart, rather than from the sinoatrial node, the normal origin of the heart's electrical activity. As with any other form of tachycardia (rapid heart beat), the underlying mechanism can be either the rapid discharge of an abnormal focus, the presence of a ring of cardiac tissue that gives rise to a circle movement (reentry), or a triggered rapid rhythm due to other pathological circumstances (as would be the case with some drug toxicities, such as digoxin toxicity). Forms of atrial tachycardia (ATach) include multifocal atrial tachycardia (MAT), focal atrial tachycardia and atrial flutter. Paroxysmal atrial tachycardia (PAT) is an episode of arrhythmia that begins and ends abruptly. Atrial tachycardia tends to occur in individuals with structural heart disease, with or without heart failure, and ischemic coronary artery disease. However, focal atrial tachycardia often occurs in healthy individuals without structural heart disease. Other possible etiologies are listed below: Hypoxia Pulmonary disease Ischemic heart disease Stimulants: cocaine, caffeine, chocolate, ephedra Alcohol Metabolic disturbances Digoxin toxicity Heightened sympathetic tone A study noted 10 to 15% of patients presenting for supraventricular tachycardia (SVT) ablation had atrial tachycardia. Electrocardiographic features include: Atrial rate: 100 to 250 BPM Ventricular conduction can be variable Irregular or irregularly irregular in the setting of variable AV block Regular if 1 to 1, 2 to 1, or 4 to 1 AV block P wave morphology Unifocal, but similar in morphology to each other Might be inverted Differs from normal sinus P wave May exhibit either long RP or short PR intervals Rhythm may be paroxysmal or sustained May demonstrate an increase in the rate at initiation (e.g., "warm up," or "rev up") May demonstrate a decrease in the rate at termination (e.