Makindo Medical Notes

Related Subjects: |Wolff-Parkinson White syndrome (WPW) AVRT |Lown Ganong Levine Syndrome AVRT |Supraventricular Tachycardia (SVT) |Atrioventricular Nodal Reentrant Tachycardia AVNRT |Atrial Flutter |Atrial Fibrillation |Sinus Tachycardia |Sinus Arrhythmia |Multifocal Atrial Tachycardia |Resuscitation - Adult Tachycardia Algorithm

Atrial Flutter Management

Important: Class I and III antiarrhythmic drugs should not be given until the rate is controlled by digoxin, beta-blockers, or calcium channel blockers. These drugs can slow the flutter rate and potentially lead to 1:1 conduction. Catheter ablation, targeting the reentrant circuit responsible for typical atrial flutter, has a success rate exceeding 90% in preventing recurrence.

About Atrial Flutter

• Atrial arrhythmia with a rate of 280-350 beats per minute.
• Always suspect atrial flutter if the ventricular rate is 150 beats per minute.

Aetiology

• Atrial flutter is a macro reentrant atrial arrhythmia.
• Typically involves the right atrium, with a rate of 280-350 beats per minute.

ECG Findings

• Sawtooth Pattern: A characteristic sawtooth appearance is seen at an atrial rate of 300 beats per minute.
• 1:1 AV Block Rate: Ventricular rate 300/min. This can occur if an accessory pathway allows conduction.
• 2:1 AV Block Rate: Ventricular rate 150/min.
• 3:1 AV Block Rate: Ventricular rate 100/min.
• 4:1 AV Block Rate: Ventricular rate 75/min.
• Carotid sinus massage or adenosine increases AV block, making flutter waves more visible on ECG.

Types of Atrial Flutter

• Type I: Due to a macro reentrant tachycardia.
• Type II: Mechanism is uncertain but differs from the typical reentrant pathway of Type I.

ECG Appearances

Causes

• Idiopathic
• Pulmonary embolism
• Atrial septal defect
• Ischaemic heart disease
• Hypertension
• Cardiomyopathy
• COPD
• Post-cardiac surgery
• Pericarditis

Clinical Presentation

• May be asymptomatic
• Common symptoms include palpitations, breathlessness, heart failure, or hypotension.

Investigations

• Blood Tests: FBC, U&E, TFTs, CRP. Troponin and BNP may also be useful.
• ECG: Suspect atrial flutter in tachyarrhythmias with a ventricular rate of 150/min. Carotid sinus massage or adenosine increases AV block and reveals flutter waves.
• Echocardiogram: Used to assess left ventricular function, valve morphology, and pericardial status.

Management

• Synchronized DC Cardioversion: First-line treatment for restoring sinus rhythm, especially if the patient is hemodynamically unstable.
• Digoxin: Increases AV block and helps slow the ventricular rate.
• Amiodarone: Can restore sinus rhythm and reduce flutter frequency.
• Catheter Ablation: Effective in targeting the single reentrant pathway in the right atrium, achieving a success rate of over 90% in preventing recurrence.
• Adenosine: Can help reveal flutter waves by increasing AV block but does not terminate the arrhythmia.
• Anticoagulation: Although the risk of thromboembolism with atrial flutter is lower than with AF, many patients receive anticoagulation due to overlapping risk factors.
• Flecainide: Can slow the flutter rate but may lead to 1:1 conduction; should be used with caution.

References

• Atrial Flutter, Typical and Atypical: A Review