New ventricular tachycardia treatment recommendations

From Ventricular Tachycardia, Emergency Medicine

New ventricular tachycardia treatment recommendations

Therapy guidelines are different for pulseless ventricular tachycardia, unstable ventricular tachycardia, and stable ventricular tachycardia. Determination of the type of ventricular tachycardia is critical before initiating therapy.

Prehospital Care

EMTs and paramedics may be called upon to provide cardioversion/defibrillation in the field if they have sufficient training and if appropriate protocols exist.

Rapid transport to an ED is essential.
EMS personnel must pay adequate attention to the primary survey and address the ABCs as necessary. Beyond those steps, vascular access, supplemental oxygen, and ECG rhythm strip monitoring are all important but should not delay rapid transport to the ED for definitive care.

Emergency Department Care

During the initial assessment, once real-time cardiac monitoring or 12-lead ECG has established VT as the diagnosis, determine if the VT is stable or unstable as the ABCs are reassessed in the primary survey.

Pulseless VT
Pulseless VT, in contrast to other unstable VT rhythms, is treated with immediate defibrillation. High-energy, unsynchronized energy should be used. The initial shock dose on a biphasic defibrillator is 200 J followed by an equal or higher shock dosage for subsequent shocks. If a monophasic defibrillator is used, the initial and subsequent shock dosage should be 360 J. Shock administration should be followed by immediate CPR, airway management, supplemental oxygen, vascular access, vasopressor agents, and then consideration of antidysrhythmic administration.
Vasopressors can include epinephrine at 1 mg IV given every 3-5 minutes, or in lieu of epinephrine, vasopressin 40 U IV as a one-time dose.
Advanced cardiac life support (ACLS) drug therapy guidelines now recommend the use of amiodarone or lidocaine as the first-line adjunctive antidysrhythmic treatment of shock-resistant pulseless VT.
Unstable VT
Unstable VT is characterized by signs/symptoms of insufficient oxygen delivery to vital organs such as chest pain, dyspnea, hypotension, or altered level of consciousness, indicating that rate and stroke volume are not providing adequate cardiac output.
In this situation, the dysrhythmia should be immediately treated with synchronized cardioversion, usually at a starting energy dose of 100 J.
In contrast, polymorphic VT is treated with immediate defibrillation as the defibrillator may have difficulty recognizing the varying QRS complexes and thus synchronizing the delivery of energy.
Antidysrhythmic therapy as outlined above for shock-resistant pulseless VT may be administered to those with shock-resistant unstable VT.
Stable VT
Stable VT usually denotes monomorphic VT with adequate vital end-organ perfusion. These patients do not experience signs/symptoms of hemodynamic compromise.
Stable VT can be treated with amiodarone, procainamide, or sotalol. Some evidence indicates that procainamide may be more effective than amiodarone in the treatment of stable VT.3, 4 In situations involving torsade de pointes, magnesium sulfate may be effective if there is a long QT interval at baseline.
Consider synchronized cardioversion early if medical therapy fails to stabilize the rhythm. Initial monophasic shock energy should be 100 J, followed by higher shock energies if the response is inadequate.
Consultations

Following initial treatment and stabilization, patients with ventricular tachycardia (VT) generally should be referred to a cardiologist for admission to a monitored bed, further studies, and definitive management.

Only rarely will a patient with stable, recurrent episodes of VT have his or her dysrhythmia treated in the ED and be discharged with appropriate follow-up care. This decision must be made in consultation with a cardiologist.