Management of Tachycardia

Initial Assessment and Stabilization

The American Heart Association recommends immediate assessment of hemodynamic stability in patients with a heart rate of 180 bpm, and proceeding directly to synchronized cardioversion if the patient shows signs of shock, altered mental status, chest pain, acute heart failure, or hypotension attributable to the tachycardia 1
The American College of Cardiology suggests providing supplementary oxygen immediately if the patient shows signs of increased work of breathing or inadequate oxyhemogation, as hypoxemia is a common cause of tachycardia 1
Attach cardiac monitor, establish IV access, and evaluate blood pressure, and obtain a 12-lead ECG to define the rhythm, but do not delay cardioversion if the patient is unstable 1
Identify and treat reversible causes (fever, anemia, hypotension, dehydration) while initiating treatment, as recommended by the American Heart Association 1, 2

The American College of Cardiology recommends adenosine as first-line therapy for stable patients with regular narrow-complex SVT, while preparations are made for cardioversion if needed 2, 3
For narrow-complex tachycardia, the initial dose of adenosine is 6 mg rapid IV push followed by NS flush, and a second dose of 12 mg if required, as suggested by the American Heart Association 4, 5, 6
For sinus tachycardia, do not treat the heart rate directly—sinus tachycardia at 180 bpm is physiologic and requires identification and treatment of the underlying cause (fever, anemia, hypotension, dehydration, hypoxia), as recommended by the American College of Cardiology 1, 2
The upper limit of sinus tachycardia is approximately 220 minus the patient's age, and critical warning is given when cardiac function is poor, cardiac output depends on rapid heart rate, and "normalizing" the rate can be detrimental 1, 2

For atrial fibrillation or flutter, pharmacologic rate control is appropriate, and beta-blockers or nondihydropyridine calcium channel blockers (diltiazem, verapamil) are first-line for rate control, as recommended by the American College of Cardiology 7, 8
Target resting heart rate <100 bpm for adequate rate control, and cardioversion should be considered if symptomatic hypotension, angina, or heart failure is present 7, 8
For ventricular tachycardia (monomorphic, stable), amiodarone is first-line: 150 mg IV over 10 minutes, followed by maintenance infusion of 1 mg/min for first 6 hours, as suggested by the American Heart Association 4, 5, 6

Never use AV nodal blocking agents (beta-blockers, calcium channel blockers, digoxin, adenosine) in patients with Wolff-Parkinson-White syndrome and wide-complex tachycardia, as they can accelerate ventricular rate and precipitate ventricular fibrillation, as warned by the American College of Cardiology 7, 8
Do not aggressively treat compensatory tachycardia in patients with poor cardiac function or shock, as stroke volume is limited and cardiac output depends on the elevated heart rate, as recommended by the American Heart Association 1, 2, 9

For hemodynamically unstable atrial fibrillation/flutter, the American College of Cardiology recommends synchronized cardioversion with 200 J for atrial fibrillation or 50 J for flutter, preceded by brief anesthesia when possible 10

The American College of Cardiology suggests obtaining a 12-lead ECG to differentiate narrow complex (<120 ms) from wide complex (>120 ms) tachycardia, and notes that wide complex tachycardia should be treated as ventricular tachycardia unless proven otherwise 11

The American College of Cardiology recommends carotid sinus massage as the initial intervention for reentrant paroxysmal SVT 10
The American College of Cardiology suggests that adenosine terminates approximately 95% of AVNRT cases, but notes that it may produce ventricular fibrillation in patients with coronary artery disease and rapid ventricular rate in pre-excited tachycardias 11
The American College of Cardiology recommends IV beta-blockers, such as metoprolol 2.5-5.0 mg every 2-5 minutes, or IV diltiazem, such as 20 mg (0.25 mg/kg) over 2 minutes, as alternative agents if adenosine fails 10

The American College of Cardiology recommends beta-blockers, such as metoprolol, or non-dihydropyridine calcium channel blockers, such as diltiazem, as first-line agents for rate control in hemodynamically stable patients 10
The American College of Cardiology suggests using IV amiodarone for rate control in patients with episodes not responding to electrical cardioversion or recurring after brief sinus rhythm 10
The American College of Cardiology recommends IV digoxin for rate control principally in patients with severe LV dysfunction and heart failure 10

The American College of Cardiology recommends amiodarone as first-line treatment for hemodynamically stable wide complex tachycardia, with a dose of 150 mg IV over 10 minutes, followed by maintenance infusion of 1 mg/min for the first 6 hours, then 0.5 mg/min 12
The American College of Cardiology suggests lidocaine or procainamide as alternative treatments for hemodynamically stable wide complex tachycardia 12
The American College of Cardiology recommends immediate unsynchronized cardioversion for polymorphic VT (200 J) and synchronized cardioversion for monomorphic VT with rates >150 bpm (100 J) in hemodynamically unstable patients 12