Approach Considerations
Electrocardiography (ECG) is essential in making the diagnosis, and can provide essential information in distinguishing "typical" from "atypical" atrial flutter. Transthoracic echocardiography (TTE) is the preferred initial imaging modality for evaluating atrial flutter.
The history and physical examination findings guide laboratory studies. Although hyperthyroidism is a rare cause of atrial flutter, asymptomatic hyperthyroidism, especially in elderly patients, can manifest as atrial fibrillation or flutter and should be excluded with thyroid function studies.
Obtain a complete blood cell count if anemia is suspected or the patient has a history of recent or current blood loss associated with the presenting symptoms. Serum electrolyte levels and pulmonary function tests may be indicated based on the history. Obtain serum electrolyte and digoxin levels if appropriate. Consider obtaining blood gas measurements in patients with hypoxia or carbon monoxide intoxication.
Chest radiography may be useful in the evaluation of lung disease and the pulmonary vasculature. Chest radiographic findings are usually normal in patients with atrial flutter, but radiographic evidence of pulmonary edema may be present in subacute cases.
Electrocardiography
In the common form of typical atrial flutter, the electrocardiogram (ECG) shows sawtooth flutter (F) waves. Flutter waves are often visualized best in leads II, III, aVF, or V1 (see the image below). The flutter waves for typical atrial flutter are inverted (negative) in leads II, III, and aVF, negative in V6, and generally positive in V1 because of a counterclockwise reentrant pathway. [11] Sometimes, they are upright (positive) when the reentrant loop is clockwise. Flutter waves (particularly 2:1) can deform the ST complex in such a manner as to mimic an ischemic injury pattern on the 12-lead ECG, and often results in erroneous interpretations on computer-based ECG diagnosis.
A 12-Lead electrocardiogram of typical atrial flutter. Note the negative sawtooth pattern of the flutter waves in leads II, III, and aVF.
In typical atrial flutter, the atrial rate is usually 250-350 beats/min. The ventricular response may be regular or irregular. In patients with typical atrial flutter, class IA and IC antiarrhythmic drugs and amiodarone can reduce the rate to approximately 200 beats/min. If this occurs, the ventricles can respond in a 1:1 fashion to the slower atrial rate. The rate in atypical flutter is usually 350-450 beats/min.
The ventricular rate reflects a fixed mathematical relation between the flutter waves and the resulting QRS complexes. Variable atrioventricular (AV) conduction can also be seen; patients commonly present with 2:1 AV conduction. With 1:1 AV conduction, hemodynamic collapse may occur. Deterioration to 1:1 conduction can occur in patients with healthy hearts, but it is a particular risk in patients with a preexcitation syndrome (Wolff-Parkinson-White). An ECG clue to a preexcitation syndrome is a very short PR interval (< 0.115 s) and delta wave.
The morphology of the flutter wave can predict findings in the electrophysiology laboratory. A negative flutter wave in the inferior limb leads and a positive flutter wave in V1 are highly predictive of a counterclockwise circuit; however, with positive flutter waves in the inferior limb leads and negative flutter waves in V1, differentiating between clockwise typical atrial flutter and atypical forms of non–isthmus-dependent intra-atrial reentry is difficult.
Diagnostic Aids
Vagal maneuvers can be helpful in determining the underlying atrial rhythm if flutter waves are not seen well. Adenosine, administered in an intravenous (IV) push followed with an IV bolus with flush, can also be helpful in making the diagnosis of atrial flutter by transiently blocking the atrioventricular node (see the image below). Approximately 15% of atrial tachycardias will also terminate with adenosine.
Rhythm strips demonstrating typical atrial flutter unmasked by adenosine (Adenocard).
Exercise testing can be utilized to identify exercise-induced atrial fibrillation and to evaluate ischemic heart disease. A Holter monitor can be used to help identify arrhythmias in patients with nonspecific symptoms, to identify triggers, and to detect associated atrial arrhythmias.
Echocardiography
Transthoracic echocardiography (TTE) is the preferred initial imaging modality for evaluating atrial flutter. It can evaluate right and left atrial size, as well as the size and function of the right and left ventricles, thereby facilitating diagnosis of valvular heart disease, left ventricular hypertrophy, and pericardial disease.
TTE has low sensitivity for intra-atrial thrombi. Transesophageal echocardiography (TEE) is the preferred technique for detecting thrombus in the left atrium.
-
Anatomy of classic counterclockwise atrial flutter. This image demonstrates an oblique view of the right atrium and shows some crucial structures. The isthmus of tissue responsible for atrial flutter is seen anterior to the coronary sinus (CS) orifice. The eustachian ridge is part of the crista terminalis that separates the roughened part of the right atrium from the smooth septal part of the right atrium. IVC = inferior vena cava; SVC = superior vena cava.
-
Typical counterclockwise atrial flutter. This 3-dimensional electroanatomic map of a tricuspid valve and right atrium shows the activation pattern displayed in color format. Red is early and blue is late, relative to a fixed point in time. Activation travels in counterclockwise direction.
-
A 12-Lead electrocardiogram of typical atrial flutter. Note the negative sawtooth pattern of the flutter waves in leads II, III, and aVF.
-
Electrocardiogram of atypical left atrial flutter.
-
3-Dimensional electroanatomic map of typical atrial flutter. Colors progress from blue to red to white and represent the relative conduction time in the right atrium (early to late). An ablation line (red dots) has been created on the tricuspid ridge extending to the inferior vena cava. This ablation line interrupts the flutter circuit. CSO = coronary sinus os; IVC = inferior vena cava; RAA = right atrial appendage; TV = tricuspid valve annulus.
-
Rhythm strips demonstrating typical atrial flutter unmasked by adenosine (Adenocard).
Tables
Type of Tachycardia |
Treatment (Grade) |
Not Mentioned in 2019 Guidelines |
Narrow QRS tachycardias |
Verapamil and diltiazem; beta-blockers (now all are grade IIa) |
Amiodarone, digoxin |
Wide QRS tachycardias |
Procainamide, adenosine (both grade IIa); amiodarone (IIb) |
Sotalol, lidocaine |
Inappropriate sinus tachycardia |
Beta-blockers (IIa) |
Verapamil/diltiazem, catheter ablation |
Postural orthostatic tachycardia syndrome |
Salt and fluid intake (IIb) |
Head-up tilt sleep, compression stockings, selective beta-blockers, fludrocortisone, clonidine, methylphenidate, fluoxetine, erythropoietin, ergotaminel octreotide, phenobarbitone |
Focal atrial tachycardia |
Acute: beta-blockers (IIa); flecainide/propafenone, amiodarone (IIb) |
Acute: procainamide, sotalol, digoxin |
Chronic: beta-blockers; verapamil and diltiazem (all IIa) |
Chronic: amiodarone, sotalol, disopyramide |
|
Atrial flutter |
Acute: ibutilide (I); verapamil and diltiazem, beta-blockers (all IIa); atrial or transesophageal pacing (IIb); flecainide/propafenone (III) |
Acute: digitalis |
Chronic: — |
Chronic: dofetilide, sotalol, flecainide, propafenone, procainamide, quinidine, disopyramide |
|
Atrioventricular nodal re-entrant tachycardia (AVNRT) |
Acute: — |
Acute: amiodarone, sotalol, flecainide, propafenone |
Chronic: verapamil and diltiazem; beta-blockers (all IIa) |
Chronic: amiodarone, sotalol, flecainide, propafenone, “pill-in-the-pocket” approach |
|
Atrioventricular re-entrant tachycardia (AVRT) |
Beta-blockers (IIa); flecainide/propafenone (IIb) |
Amiodarone, sotalol, “pill-in-the-pocket” approach |
SVT in pregnancy |
Verapamil (IIa); catheter ablation (IIa when fluoroless ablation is available) |
Sotalol, propafenone, quinidine, procainamide |
Adapted from Brugada J, Katritsis DG, Arbelo E, et al, for the ESC Scientific Document Group. 2019 ESC Guidelines for the management of patients with supraventricular tachycardia. The Task Force for the management of patients with supraventricular tachycardia of the European Society of Cardiology (ESC). Eur Heart J. 2019 Aug 31;ehz467. https://academic.oup.com/eurheartj/advance-article/doi/10.1093/eurheartj/ehz467/5556821 |
||
