Premature Atrial Contractions and Associated Risks
Causes and Triggers
- Underlying structural heart disease can manifest with PACs, particularly in patients with prior congenital heart surgery or significant hemodynamic abnormalities 2
- Drug-induced causes include medications such as adenosine, theophylline/aminophylline, and various chemotherapeutic agents 1
Symptomatic Effects
- Yes, PACs can cause dizziness along with other symptoms including palpitations, fatigue, chest discomfort, dyspnea, lightheadedness, or syncope 2
- The mechanism relates to hemodynamic effects on blood pressure and cardiac output, similar to other arrhythmias 1
- The American College of Cardiology and American Heart Association guidelines specifically define syncope as transient loss of consciousness, explicitly stating it is "not light-headedness or dizziness alone" 3, 4
Clinical Approach
- Any PAC causing symptoms, including dizziness, warrants diagnostic workup regardless of frequency 2
- Obtain 24-hour Holter monitoring to capture the arrhythmia, quantify burden, and correlate symptoms with PAC occurrence 2
- Frequent PACs (>2,000 per 24 hours) require comprehensive evaluation due to substantially increased risk of atrial fibrillation, stroke, and adverse atrial remodeling 2
- Athletes with ≥2 PACs on a single 12-lead ECG should undergo extensive evaluation including Holter monitoring, echocardiogram, and exercise stress testing 2
- In healthy, asymptomatic individuals with isolated PACs, no structural heart disease, and normal thyroid function, no further evaluation or therapy is required 2