Cardiac Arrhythmia Management

Introduction to Bradycardia

Bradycardia is defined as a heart rate less than 60 beats per minute and can range from a benign physiological finding to a life-threatening condition requiring immediate intervention, depending on the presence of symptoms and hemodynamic compromise, as stated by the American College of Cardiology and the American Heart Association 1, 2
The American College of Cardiology recommends obtaining a 12-lead ECG to identify the specific bradyarrhythmia, as this is crucial for differentiating between various types of bradycardia and guiding management decisions 2
The American Heart Association suggests checking oxygen saturation, as hypoxemia is a common cause of bradycardia, and establishing IV access for potential emergency interventions 3

Bradycardia can be broadly classified into two general categories: Sinus Node Dysfunction (SND) and Atrioventricular (AV) Block, according to the American College of Cardiology 1, 2
The American College of Cardiology advises differentiating between sinus node dysfunction and atrioventricular (AV) block based on ECG findings, including sinus bradycardia, sinus arrest or pause, sinoatrial exit block, and chronotropic incompetence 2
The American Heart Association recommends identifying first-degree AV block (PR interval >0.20 seconds), second-degree AV block (Mobitz type I or II), and third-degree (complete) AV block, as these conditions have distinct management approaches 3
Potential causes of bradycardia include degenerative fibrosis of the conduction system (age-related), ischemic heart disease, infiltrative diseases (amyloidosis, sarcoidosis), inflammatory conditions (myocarditis, endocarditis), congenital heart disease, and surgical trauma, as stated by the American College of Cardiology 1, 2
Medications such as beta-blockers, non-dihydropyridine calcium channel blockers, digoxin, antiarrhythmic drugs, and centrally-acting agents can induce bradycardia, as reported by the American College of Cardiology 1, 2
Risk factors for bradycardia include advanced age (>70 years), pre-existing cardiac disease, renal or hepatic dysfunction, electrolyte abnormalities, and concomitant use of multiple bradycardia-inducing medications, as identified by the American College of Cardiology 1, 2

Symptoms of bradycardia vary widely and may include syncope or presyncope, dizziness or lightheadedness, fatigue, dyspnea, chest pain, heart failure symptoms, confusion or altered mental status, and Morgagni-Adams-Stokes seizures, as reported by the American College of Cardiology and the American Heart Association 1, 2
Symptomatic bradycardia refers to documented bradyarrhythmia directly responsible for symptoms resulting from cerebral hypoperfusion due to slow heart rate, as defined by the American College of Cardiology and the American Heart Association 1, 2

The American College of Cardiology emphasizes the importance of reviewing all medications, including over-the-counter and nutraceuticals, as common culprits such as beta-blockers, calcium channel blockers, digoxin, amiodarone, and clonidine can contribute to bradycardia 2
First-line pharmacologic therapy for bradycardia includes atropine 0.5-1 mg IV every 3-5 minutes (maximum 3 mg), as recommended by the American College of Cardiology 1, 2
Second-line options for bradycardia treatment include dopamine infusion (2-10 μg/kg/min), epinephrine infusion (2-10 μg/min), and isoproterenol infusion (2-10 μg/min), as stated by the American College of Cardiology 1, 2

The American College of Cardiology recommends ambulatory ECG monitoring (24-hour Holter, event recorder), exercise testing for chronotropic incompetence, and electrophysiologic studies for suspected conduction system disease, as these tests can help clarify the diagnosis and guide management in unclear cases 2
Temporary pacing for refractory cases, including transcutaneous pacing (emergency) and transvenous pacing (bridge to permanent pacing), may be necessary, as recommended by the American College of Cardiology 1, 2
Permanent pacemaker implantation is indicated for symptomatic sinus node dysfunction, high-grade (second-degree Mobitz II or third-degree) AV block, and symptomatic bradycardia without reversible causes, as stated by the American College of Cardiology 1, 2

Avoid combining multiple bradycardia-inducing medications when possible, as recommended by the American College of Cardiology 1, 2
Monitor heart rate and blood pressure regularly in at-risk patients, as stated by the American College of Cardiology 1, 2
Adjust medication doses appropriately in elderly patients and those with renal/hepatic impairment, as recommended by the American College of Cardiology 1, 2
Be vigilant for drug interactions that increase levels of bradycardia-inducing drugs, as stated by the American College of Cardiology 1, 2
Regular vital sign assessment in postoperative patients is crucial, as recommended by the American College of Cardiology 1, 2