Management

2. Rhythm Control:

    b. Non-pharmacologic Options

1) Direct-current cardioversion

Direct-current cardioversion is characterized by a synchronized electrical discharge, terminating the arrhythmia by sensing the R wave of the electrocardiogram, ensuring that no electrical current is discharged during a vulnerable period of the cardiac cycle.  Direct-current cardioversion is indicated in patients with hemodynamic instability manifesting signs of heart failure, and angina.  A successful cardioversion highly dependents on the underlying heart disease and duration of atrial fibrillation.  A long standing arrhythmia, and a dilated left atrium make the rate of success much less likely.  As in pharmacologic cardioversion, it should always happen under adequate anticoagulation, or with documentation of a negative transesophageal echocardiogram.  Sedation should also be given and the patient fasting.  An initial energy of 100J is recommended which can be increased up to 200J as needed.  In patient with pacemaker and defibrillator device, interrogation post cardioversion should be undertaken to ensure adequate function. 

2) Ablation

In refractory cases, atrioventricular node ablation in conjunction with permanent pacemaker implantation provides a highly effective mean to control the heart rate while offering symptomatic relieve.  This irreversible technique offers limitation has the patient will require lifelong anticoagulation and pacemaker dependency. 

Surgical ablation is capable of terminating macroreentrant circuits within the atria while preserving sinus node and atrial transport function.  Ablation can also be referred to as “maze” procedure.  This technique has a high success rate up to 70-90%.  This procedure is usually reserve for people undergoing cardiac surgery as it requires cardio-pulmonary bypass.


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