Cardiac Arrhythmia Management

Initial Assessment and Treatment

• The British Journal of Sports Medicine recommends determining if a patient has a pulse and assessing hemodynamic stability, checking for adverse signs such as low blood pressure, chest pain, heart failure, or high heart rate 1
• For life-threatening arrhythmias, the British Journal of Sports Medicine suggests administering drugs intravenously, always followed by a 20 ml saline bolus to aid delivery to the central circulation 2
• When no venous access is possible, the British Journal of Sports Medicine recommends that drugs, particularly adrenaline, may be delivered via the endotracheal route in double or triple doses 2

Treatment of Ventricular Arrhythmias

• The British Journal of Sports Medicine recommends early defibrillation as the primary intervention for Ventricular Fibrillation (VF)/Pulseless Ventricular Tachycardia (VT), with pharmacological treatment considered secondary 2
• For refractory VF/pulseless VT, the British Journal of Sports Medicine suggests considering antiarrhythmic drugs 2
• The British Journal of Sports Medicine recommends that magnesium may be effective for VF/VT, particularly when associated with acute myocardial infarction (8 mmol bolus followed by 2.5 mmol/h infusion) 2
• For unstable VT with pulse, the British Journal of Sports Medicine recommends immediate synchronized DC cardioversion (100J, 200J, 360J) with prior sedation if the patient is conscious 2, 1
• For stable VT, the British Journal of Sports Medicine suggests that lidocaine (lignocaine) is the first-choice antiarrhythmic, given intravenously at 50 mg over 2 minutes, repeated every 5 minutes to a total dose of 200 mg, followed by maintenance infusion at 2 mg/min 2, 1
• The British Journal of Sports Medicine recommends that amiodarone is indicated for VT refractory to lidocaine, given at 5 mg/kg (300 mg) over one hour for stable patients, or over 15 minutes in life-threatening situations 2, 1
• For refractory VT that doesn't respond to other agents, the British Journal of Sports Medicine suggests using bretylium (5 mg/kg diluted with 100 ml dextrose, with a possible further dose of 10 mg/kg) 2, 3

Treatment of Supraventricular Arrhythmias

• For hemodynamically unstable patients with Supraventricular Tachycardia (SVT), the British Journal of Sports Medicine recommends sedation and treatment with cardioversion 3
• For stable patients with SVT, the British Journal of Sports Medicine suggests trying vagal maneuvers (Valsalva maneuver or unilateral carotid artery pressure if no carotid bruit) 3
• The British Journal of Sports Medicine recommends that adenosine is the drug of choice for AV nodal re-entrant tachyarrhythmias (3 mg rapid bolus with saline flush, then 6 mg if no effect after 1-2 minutes, maximum 12 mg) 4, 3
• For definite SVT, the British Journal of Sports Medicine suggests using verapamil (5-10 mg over 60 seconds), but it is contraindicated if β-blockers have been taken or in SVTs associated with Wolff-Parkinson-White syndrome 4, 3

Treatment of Bradyarrhythmias

• The British Journal of Sports Medicine recommends that transient bradycardias are common in acute myocardial infarction, particularly inferior MI 4
• For bradycardia <40 beats/min or associated with signs of cardiac failure or type II heart block, the British Journal of Sports Medicine suggests treating initially with atropine (0.5 mg up to 3 mg, titrated according to heart rate response) 4, 3
• For patients with pauses >3 seconds, Mobitz type II heart block, type II heart block with anterior MI, or previous asystole, the British Journal of Sports Medicine recommends preparing immediately for temporary cardiac pacing 4, 3

Important Considerations and Precautions

• The British Journal of Sports Medicine warns that adenosine must be given in a monitored environment (e.g., critical care unit or emergency department) as it can cause transient complete heart block 4
• The British Journal of Sports Medicine recommends that adenosine should not be routinely used in asthmatic patients due to risk of bronchospasm 4
• The British Journal of Sports Medicine warns that verapamil is contraindicated if β-blockers have been taken due to risk of profound bradycardia and hypotension 4
• The British Journal of Sports Medicine recommends that verapamil should not be used for SVTs associated with Wolff-Parkinson-White syndrome as it may precipitate VT/VF 4
• The British Journal of Sports Medicine warns that most antiarrhythmic drugs depress myocardial contractility and require careful monitoring, especially in hemodynamically compromised patients 2

Management of Ventricular Tachycardia with Pulse but Hypotension

Initial Assessment and Management

• For ventricular tachycardia with pulse but hypotension (systolic BP ≤ 90 mm Hg), immediate synchronized DC cardioversion with appropriate sedation is the recommended first-line treatment, as suggested by the European Society of Cardiology 5, 6
• The European Heart Society recommends considering VT with pulse but hypotension as a hemodynamically unstable condition requiring immediate intervention 6, 7
• If the patient is conscious but hypotensive, the European Heart Society recommends providing immediate sedation before proceeding with cardioversion 6

Treatment Algorithm for VT with Pulse but Hypotension

• The European Society of Cardiology recommends performing immediate synchronized DC cardioversion starting at 100J, then 200J, then 360J as needed 5, 6
• For patients who are conscious but hypotensive, the European Heart Society recommends administering sedation prior to cardioversion 6

Pharmacological Considerations

• The European Society of Cardiology suggests considering amiodarone as a treatment option for hemodynamically unstable VT refractory to other therapy, with a loading dose of 150 mg over 10 minutes 5
• The British Journal of Sports Medicine recommends considering lidocaine as an alternative or additional therapy, particularly when VT is thought to be related to myocardial ischemia 5, 7
• The European Society of Cardiology recommends procainamide as a reasonable option for initial treatment if the patient stabilizes after cardioversion 5

Important Cautions

• The European Society of Cardiology advises against using calcium channel blockers such as verapamil and diltiazem in patients with VT, especially in those with myocardial dysfunction 5
• The European Society of Cardiology recommends monitoring blood pressure and cardiovascular status closely when administering antiarrhythmic medications, particularly in patients with heart failure 5
• The European Heart Society recommends correcting electrolyte abnormalities, particularly potassium and magnesium 6

Lignocaine (Lidocaine) Dosing for Ventricular Tachycardia

Initial Assessment and Management

• For pulseless VT, the British Journal of Sports Medicine recommends following the ventricular fibrillation protocol with immediate defibrillation as the primary intervention 8, 9
• For VT with pulse but hemodynamic instability, the British Journal of Sports Medicine suggests performing immediate synchronized DC cardioversion (100J, 200J, 360J) with sedation if the patient is conscious 8

Lignocaine (Lidocaine) Dosing for VT

• The American College of Cardiology recommends an initial bolus of 1-3 mg/kg IV lignocaine (not exceeding 100 mg), followed by a maintenance infusion of 2-4 mg/min if cardioversion is successful 8, 10
• For cardiac arrest/pulseless VT, the British Journal of Sports Medicine recommends an initial bolus of 100 mg IV lignocaine, which may be repeated after 5-10 minutes if needed, and maintained with an infusion at 2-4 mg/min 8
• For stable VT with pulse, the British Journal of Sports Medicine suggests an initial dose of 50 mg IV lignocaine over 2 minutes, which may be repeated every 5 minutes to a total dose of 200 mg, and maintained with an infusion at 2 mg/min 8, 9
• The American College of Cardiology recommends an alternative dosing regimen, including a loading dose of 1 mg/kg IV lignocaine (not exceeding 100 mg), additional boluses of 0.5 mg/kg every 8-10 minutes if necessary, and a maintenance infusion of 20-50 μg/kg/min (1.4-3.5 mg/min in a 70 kg patient) 10

Important Considerations

• The American College of Cardiology recommends that patients who require more than one bolus dose of lignocaine may need higher maintenance doses (up to 40-50 μg/kg/min) 10
• The American College of Cardiology suggests reducing the infusion rate after 24-48 hours as the half-life of lidocaine increases over time 10
• The American College of Cardiology recommends decreasing the dose in patients with myocardial infarction, cardiac failure, or cardiogenic shock 10

Monitoring and Toxicity

• The American College of Cardiology recommends monitoring for signs of toxicity, including central nervous system symptoms (nausea, drowsiness, perioral numbness, dizziness, confusion, slurred speech) and more severe symptoms (muscle twitching, seizures, respiratory depression) 10
• The British Journal of Sports Medicine suggests that lidocaine depresses myocardial contractility, requiring careful monitoring especially in hemodynamically compromised patients 8

Special Situations

• The British Journal of Sports Medicine recommends considering bretylium (5 mg/kg diluted with 100 ml dextrose, with possible further dose of 10 mg/kg) for refractory VT 8