![]() Thus, patients should be anticoagulated for 4 weeks prior to DCCV, or TEE performed to rule out LA clot (see attached NEJM paper).As in atrial fibrillation, flutter >48h carries a risk of post-cardioversion embolism (~1% risk).Pharmacologic: less effective, and agents carry some proarrhythmic risk.DCCV: requires conscious sedation, which may compromise hemodynamics.Restoration of NSR: improves hemodynamics, decreases oxygen demand, and alleviates symptoms.Thus, negative inotropy can drop CO and BP.In atrial flutter, preload is impaired due to shortened diastolic filling time.Remember that CO = HR x SV, and SV = contractility x preload.Digoxin: slow onset of action, and dependent on vagal tone for effect however, has positive inotropic effects.Amiodarone: has some negative inotropic effects, and can also cause unintended cardioversion.BB (metoprolol, esmolol): also negative inotropes.CCB (verapamil, diltiazem): negative inotropes, and cause peripheral vasodilation.In addition, AV node is less refractory than in atrial fibrillation, and thus high doses of AV nodal blocking agents can be required.Rate control: can be difficult, given that ventricular rate drops in fixed intervals (e.g.Electrically unstable, and often degenerates into atrial fibrillation or reverts to sinus rhythm.Pathophysiology: macroreentrant rhythm, typically involving tricuspid annulus.Dependent: arrhythmia terminates upon interruption of AV nodal conduction.Independent: arrhythmia persists despite interruption of AV nodal conduction.AV nodal dependence: whether or not AV node is part of reentrant circuit.Long: suggests atrial tachycardia or sinus tachycardia.Very short: suggests typical AVNRT, given rapid retrograde conduction.RP interval: distance from R wave to P wave (see attached Mayo Clin Proc review).Sinus P waves are positive in inferior leads, I, and aVL, negative/biphasic in V1, and negative in aVR.P wave morphology: all P waves are not sinus!.Avoid in patients with asthma, or post-heart transplant.Adverse effects: nausea, flushing, chest tightness, hypotension, heart block, asystole.Adenosine has half-life of less than 10 seconds, and thus must be pushed rapidly followed immediately by flush (use two-way stopcock).Maneuvers: carotid sinus massage (check for bruits, hx CVA), valsalva, cold water to face, adenosine.Vagolytic maneuvers can help identify atrial activity, as well as provide information regarding AV nodal dependence if arrhythmia terminates.Regular: sinus tachycardia, atrial flutter, atrial tachycardia, sinus node reentrant tachycardia, AVNRT, AVRT, junctional tachycardia.Irregular: atrial fibrillation, flutter with variable conduction, MAT. ![]()
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