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Tachycardia: Difference between revisions
→Atrial Flutter
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===Atrial Flutter=== | ===Atrial Flutter=== | ||
====Pathophysiology:==== | ====Pathophysiology:==== | ||
Atrial flutter (AFT) is the most common type of atrial tachycardia. The typical atrial flutter is dependent of the cavotricuspid isthmus. The isthmus between the caval vein and tricuspid is an area of slow conduction. Due to this slow conduction counterclockwise re-entry around the tricuspid annulus can exist. This re-entry produces a typical arrhythmia with activates the atria at a frequency between 250-350 beats per minute. If the re-entry circuit moves counterclockwise a typical AFT is produced. If the re-entry circuit moves clockwise, a atypical AFT is seen. The causes and risk are comparable with atrial fibrillation. | Atrial flutter (AFT) is the most common type of atrial tachycardia. The typical atrial flutter is dependent of the cavotricuspid isthmus.<cite>Saoudi</cite> The isthmus between the caval vein and tricuspid is an area of slow conduction. Due to this slow conduction counterclockwise re-entry around the tricuspid annulus can exist. This re-entry produces a typical arrhythmia with activates the atria at a frequency between 250-350 beats per minute. If the re-entry circuit moves counterclockwise a typical AFT is produced. If the re-entry circuit moves clockwise, a atypical AFT is seen. The causes and risk are comparable with atrial fibrillation. | ||
====Clinical diagnosis:==== | ====Clinical diagnosis:==== | ||
An AFT is usually paroxysmal, with a sudden onset, and is diagnosed on the ECG by it typical sawtooth pattern and atrial frequency. Patients experience complaints of palpitations, dyspneu, fatigue or chest pain. An AFT has a frequency of 300 bpm, which conducts to the ventricles in 2:1, 3:1 or 4:1 manner. The P-wave morphology has a sawtooth like appearance and in a typical AFT has a negative vector in the inferior leads. The first part of the P-wave is fast, the second path slow. In a atypical AFT the inferior leads have a positive vector. Atrial fibrillation is a common finding in patients with an atrial flutter (up to 35%). | An AFT is usually paroxysmal, with a sudden onset, and is diagnosed on the ECG by it typical sawtooth pattern and atrial frequency. Patients experience complaints of palpitations, dyspneu, fatigue or chest pain. An AFT has a frequency of 300 bpm, which conducts to the ventricles in 2:1, 3:1 or 4:1 manner. The P-wave morphology has a sawtooth like appearance and in a typical AFT has a negative vector in the inferior leads. The first part of the P-wave is fast, the second path slow. In a atypical AFT the inferior leads have a positive vector. Atrial fibrillation is a common finding in patients with an atrial flutter (up to 35%). | ||
====Management:==== | ====Management:==== | ||
In a acute episode a patient with an AFT requires cardioversion. This can be achieved with anti-arrhythmic drugs or electrical cardioversion. Vagal maneuvers increase the AV-block on the ECG and demonstrate the AFT more clearly. Anti-arrhythmic drugs are modestly effective in the acute setting (ibutilide or dofetilide), but have the risk of pro-arrhythmic effects. DC cardioversion is an effective methods to cardiovert AFT, especially in patients with heart failure or hemodynamic instability. AFT is amendable to catheter ablation and this is the treatment of choice in AFT. Targeted ablation of the area between the inferior vena cava and the tircuspid annulus can block the re-entry circuit. This is a very successful procedure, with few complications in the hands of an experienced electrophysiologist. If patients are not eligible for ablation, anti-arrhythmic drugs class IC or III can be started. However they are of limited efficacy and class IC drugs not be administered without AV-nodal slowing agent because of atrial slowing can result in 1:1 AV conduction. Patients with AFT require anti-coagulation as in atrial fibrillation according to the CHADSVASc score. | In a acute episode a patient with an AFT requires cardioversion. This can be achieved with anti-arrhythmic drugs or electrical cardioversion. Vagal maneuvers increase the AV-block on the ECG and demonstrate the AFT more clearly. Anti-arrhythmic drugs are modestly effective in the acute setting (ibutilide or dofetilide), but have the risk of pro-arrhythmic effects.<cite>Volgmann</cite> DC cardioversion is an effective methods to cardiovert AFT, especially in patients with heart failure or hemodynamic instability. AFT is amendable to catheter ablation and this is the treatment of choice in AFT. Targeted ablation of the area between the inferior vena cava and the tircuspid annulus can block the re-entry circuit. This is a very successful procedure, with few complications in the hands of an experienced electrophysiologist. If patients are not eligible for ablation, anti-arrhythmic drugs class IC or III can be started. However they are of limited efficacy and class IC drugs not be administered without AV-nodal slowing agent because of atrial slowing can result in 1:1 AV conduction. Patients with AFT require anti-coagulation as in atrial fibrillation according to the CHADSVASc score. | ||
===Atrial Fibrillation=== | ===Atrial Fibrillation=== | ||