ESSENTIALS OF DIAGNOSIS
Rapid, regular tachycardia presenting classically with 2 to 1 block in the AV node and ventricular heart rate of 150 beats/minute. ECG shows “sawtooth” pattern of atrial activity (rate 300 beats/minute).
Stroke risk should be considered equivalent to that with atrial fibrillation.
Catheter ablation is highly successful and is considered the definitive treatment for typical atrial flutter.
Atrial flutter is less common than fibrillation. It may occur in patients with structurally normal hearts but is more commonly seen in patients with COPD, valvular or structural heart disease, ASD, or surgically repaired congenital heart disease.
Patients typically present with complaints of palpitations, fatigue, or mild dizziness. In situations where the arrhythmia is unrecognized for a prolonged period of time, patients may present with symptoms and signs of heart failure (dyspnea, exertional intolerance, edema) due to tachycardia-induced cardiomyopathy. The ECG typically demonstrates a “sawtooth” pattern of atrial activity in the inferior leads (II, III, and AVF). The reentrant circuit generates atrial rates of 250–350 beats/minute, usually with transmission of every second, third, or fourth impulse through the AV node to the ventricles (eFigures 10–62, 10–63, and 10–64).
Atrial flutter. A: Regular, narrow-complex tachycardia at a ventricular rate of 155 beats/min. B: Atrial flutter with flutter waves most visible in leads 2, 3, and aVF. C: Atrial flutter response to carotid sinus massage inducing transient AV block and unmasking flutter waves. (Reproduced, with permission, from Tintinalli JE, Ma OJ, Yealy DM, et al. Tintinalli's Emergency Medicine: A Comprehensive Study Guide, 9th ed. McGraw-Hill, 2020.)
Atrial flutter with sinus bradycardia. Typical atrial flutter with bradycardia to 42 beats per minute. (Reproduced with permission from Jose Sanchez, MD.)
Atrial flutter with complete heart block. An ectopic junctional rhythm is noted. (Reproduced with permission from Jose Sanchez, MD.)
Ventricular rate control is accomplished using the same agents used in atrial fibrillation, but it is generally more difficult. Conversion of atrial flutter to sinus rhythm with class I antiarrhythmic agents is also difficult to achieve, and administration of these medications has been associated with slowing of the atrial flutter rate to the point at which 1:1 AV conduction can occur at rates in excess of 200 beats/minute, with subsequent hemodynamic collapse. The intravenous class III antiarrhythmic agent ibutilide has been significantly more successful in converting atrial flutter (see Table 10–9). About 50–70% of patients return to sinus rhythm within 60–90 minutes following the infusion of 1–2 mg of this agent. Electrical cardioversion is also ...