Part 7.3: Management of Symptomatic Bradycardia and Tachycardia V exceed I mg/min. May repeat total dose in 2 minutes if Lidocaine Lidocaine is one of a number of antiarrhythmic dr IV esmolol is a short-acting(half-life 2 to 9 minutes) available for treatment of ventricular ectopy, VT, and VE Br-selective B-blocker that is administered in an IV loading this time there is good evidence that alternative agents dose of 500 ug/kg(0.5 mg/kg) over I minute, followed by a superior to lidocaine in terminating VT. 46 Lidocaine may be 4-minute infusion of 50 ug/kg per minute(0.05 mg/kg per considered in the following conditions(although it is not minute)for a total of 200 ug/kg. If the response is inadequate, considered the drug of choice) a second bolus of 0. 5 mg/kg is infused over I minute, with increase of the maintenance infusion to 100 ug/kg(0.1 For stable monomorphic VT in patients with preserved mg/kg) per minute(maximum infusion rate: 300 ug/kg [0.3 rentricular function (Class Indeterminate). Alternative mg/kgl per minute). agents are preferred Side effects related to B-blockade include bradycardias, For polymorphic VT with normal baseline QT interval AV conduction delays, and hypotension. Cardiovascular de- hen ischemia is treated and electrolyte imbalance is corrected cardiogenic shock after B-adrenergic If ventricular function is preserved: lidocaine may be blocker therapy are infrequent complications. Contraindica tions to the use of B-adrenergic blocking agents include If ventricular function is impaired: use amiodarone as ar second-degree or third-degree heart block, hypotension, se- antiarrhythmic agent. If unsuccessful, perform DC vere congestive heart failure, and lung disease associated with cardioversion bronchospasm.These agents may be harmful for patients with Lidocaine can be used for polymorphic VT with a pro- atrial fibrillation or atrial flutter associated with known longed baseline QT interval that suggests torsades de pre-excitation (WPW) syndrome Initial doses ranging from 0.5 to 0. 75 mg/kg and up to I to ilide is a short-acting antiarrhythmic that acts by prolong- 1.5 mg/kg may be used. Repeat 0.5 to 0.75 mg/kg every 5 to ing the action potential duration and increasing the refractory 10 minutes to a maximum total dose of 3 mg/kg. A mainte period of cardiac tissue. This agent may be used in the nance infusion of I to 4 mg/min(30 to 50 ug/kg per minute) For acute pharmacologic rhythm conversion of atrial fibril Toxic reactions and side effects include slurred speech, lation or atrial flutter in patients with normal cardiac altered consciousness, muscle twitching, seizures, and function when duration of the arrhythmia is $48 hours bradycardia (Class Ib).39 Magnesium To control rate in atrial fibrillation or atrial flutter Magnesium is recommended for the treatment of torsades de patients with preserved ventricular function when calcium pointes VT with or without cardiac arrest, but it has not been channel blockers or B-blockers are ineffectie shown to be helpful for treatment of non-torsades pulseless For acute pharmacologic rhythm conversion of atrial fibril- arrest. Low-level evidence suggests that magnesium is effec- lation or atrial flutter in patients with WPW syndrome and tive for rate control (LOE 3)34 in patients with atrial fibrilla preserved ventricular function when the duration of the tion with a rapid ventricular response(LoE 2), 0 so it may be arrhythmia is <48 hours. But the intervention of choice for considered for this arrhythmia. s indication is dc cardioversion Give magnesium sulfate in a dose of I to 2 g diluted in D5 w over 5 to 60 minutes Slower rates are preferable in the Ibutilide seems most effective for the pharmacologic con- stable patient. A more rapid infusion may be used for the version of atrial fibrillation or atrial flutter of relatively brief unstable patient duration For adults weighing 260 kg, ibutilide is adminis tered intravenously, diluted or undiluted, as I mg (10 mL) Procainamide over 10 minutes. If the first dose is unsuccessful in terminat Procainamide hydrochloride suppresses both atrial and ven- ing the arrhythmia, a second I-mg dose can be administered tricular arrhythmias by slowing conduction in myocardial at the same rate 10 minutes after the first. In patients tissue. One randomized trial (Loe 2)7 indicated that pro- weighing <60 kg, an initial dose of 0.01 mg/kg ainamide is superior to lidocaine in terminating spontane- recommended ously occurring VT. Procainamide may be considered in the Ibutilide has minimal effects on blood pressure and heart following situations rate. Its major limitation is a relatively high incidence of As one of several drugs that may be used for treatment of ventricular arrhythmia stable monomorphic VT in patients with preserved ventric- de pointes). Correct hyperkalemia or low magnesium before ular function( Class Ila)46 administration. Monitor patients receiving ibutilide continu- One of several equivalent drugs that can be used for control ously for arrhythmias at the time of its administration and for of heart rate in atrial fibrillation or atrial flutter in patients at least 4 to 6 hours thereafter. ibutilide is contraindicated in with preserved ventricular function baseline QTc(QT interval corrected for heart rate)of >440 One of several drugs that can be used for acute control of heart rhythm in atrial fibrillation or atrial flutter in patientsexceed 1 mg/min. May repeat total dose in 2 minutes if necessary. IV esmolol is a short-acting (half-life 2 to 9 minutes) 1-selective -blocker that is administered in an IV loading dose of 500
g/kg (0.5 mg/kg) over 1 minute, followed by a 4-minute infusion of 50
g/kg per minute (0.05 mg/kg per minute) for a total of 200
g/kg. If the response is inadequate, a second bolus of 0.5 mg/kg is infused over 1 minute, with an increase of the maintenance infusion to 100
g/kg (0.1 mg/kg) per minute (maximum infusion rate: 300
g/kg [0.3 mg/kg] per minute). Side effects related to -blockade include bradycardias, AV conduction delays, and hypotension. Cardiovascular de￾compensation and cardiogenic shock after -adrenergic blocker therapy are infrequent complications. Contraindica￾tions to the use of -adrenergic blocking agents include second-degree or third-degree heart block, hypotension, se￾vere congestive heart failure, and lung disease associated with bronchospasm. These agents may be harmful for patients with atrial fibrillation or atrial flutter associated with known pre-excitation (WPW) syndrome. Ibutilide Ibutilide is a short-acting antiarrhythmic that acts by prolong￾ing the action potential duration and increasing the refractory period of cardiac tissue. This agent may be used in the following circumstances: ● For acute pharmacologic rhythm conversion of atrial fibril￾lation or atrial flutter in patients with normal cardiac function when duration of the arrhythmia is 48 hours (Class IIb).39 ● To control rate in atrial fibrillation or atrial flutter in patients with preserved ventricular function when calcium channel blockers or -blockers are ineffective. ● For acute pharmacologic rhythm conversion of atrial fibril￾lation or atrial flutter in patients with WPW syndrome and preserved ventricular function when the duration of the arrhythmia is 48 hours. But the intervention of choice for this indication is DC cardioversion. Ibutilide seems most effective for the pharmacologic con￾version of atrial fibrillation or atrial flutter of relatively brief duration. For adults weighing 60 kg, ibutilide is adminis￾tered intravenously, diluted or undiluted, as 1 mg (10 mL) over 10 minutes. If the first dose is unsuccessful in terminat￾ing the arrhythmia, a second 1-mg dose can be administered at the same rate 10 minutes after the first. In patients weighing
60 kg, an initial dose of 0.01 mg/kg is recommended. Ibutilide has minimal effects on blood pressure and heart rate. Its major limitation is a relatively high incidence of ventricular arrhythmias (polymorphic VT, including torsades de pointes). Correct hyperkalemia or low magnesium before administration. Monitor patients receiving ibutilide continu￾ously for arrhythmias at the time of its administration and for at least 4 to 6 hours thereafter. Ibutilide is contraindicated in baseline QTC (QT interval corrected for heart rate) of 440 msec. Lidocaine Lidocaine is one of a number of antiarrhythmic drugs available for treatment of ventricular ectopy, VT, and VF. At this time there is good evidence that alternative agents are superior to lidocaine in terminating VT.46 Lidocaine may be considered in the following conditions (although it is not considered the drug of choice): ● For stable monomorphic VT in patients with preserved ventricular function (Class Indeterminate). Alternative agents are preferred. ● For polymorphic VT with normal baseline QT interval when ischemia is treated and electrolyte imbalance is corrected. ● If ventricular function is preserved: lidocaine may be administered. ● If ventricular function is impaired: use amiodarone as an antiarrhythmic agent. If unsuccessful, perform DC cardioversion. ● Lidocaine can be used for polymorphic VT with a pro￾longed baseline QT interval that suggests torsades de pointes. Initial doses ranging from 0.5 to 0.75 mg/kg and up to 1 to 1.5 mg/kg may be used. Repeat 0.5 to 0.75 mg/kg every 5 to 10 minutes to a maximum total dose of 3 mg/kg. A mainte￾nance infusion of 1 to 4 mg/min (30 to 50
g/kg per minute) is acceptable. Toxic reactions and side effects include slurred speech, altered consciousness, muscle twitching, seizures, and bradycardia. Magnesium Magnesium is recommended for the treatment of torsades de pointes VT with or without cardiac arrest, but it has not been shown to be helpful for treatment of non-torsades pulseless arrest. Low-level evidence suggests that magnesium is effec￾tive for rate control (LOE 3)34 in patients with atrial fibrilla￾tion with a rapid ventricular response (LOE 2),40 so it may be considered for this arrhythmia. Give magnesium sulfate in a dose of 1 to 2 g diluted in D5W over 5 to 60 minutes. Slower rates are preferable in the stable patient. A more rapid infusion may be used for the unstable patient. Procainamide Procainamide hydrochloride suppresses both atrial and ven￾tricular arrhythmias by slowing conduction in myocardial tissue. One randomized trial (LOE 2)47 indicated that pro￾cainamide is superior to lidocaine in terminating spontane￾ously occurring VT. Procainamide may be considered in the following situations: ● As one of several drugs that may be used for treatment of stable monomorphic VT in patients with preserved ventric￾ular function (Class IIa)46 ● One of several equivalent drugs that can be used for control of heart rate in atrial fibrillation or atrial flutter in patients with preserved ventricular function ● One of several drugs that can be used for acute control of heart rhythm in atrial fibrillation or atrial flutter in patients Part 7.3: Management of Symptomatic Bradycardia and Tachycardia IV-75