From the Guidelines
Premature atrial contractions (PACs) are generally benign and do not require specific treatment, unless they cause significant symptoms, in which case lifestyle modifications and medications such as beta-blockers or calcium channel blockers may be considered. PACs are early heartbeats that originate in the atria rather than the normal pacemaker of the heart. According to the 2023 ACC/AHA/ACCP/HRS guideline for the diagnosis and management of atrial fibrillation, PACs can contribute to the development of atrial fibrillation (AF) by creating a substrate for reentry and providing triggers that can initiate arrhythmic activity 1. The pathways that contribute to the development of AF, including PACs, involve various mechanisms such as RAAS activation, fibrotic and adipocyte signaling, and atrial hypertrophy; cardiomyopathy.
Some of the key factors that can contribute to the development of PACs include:
- Hypertension, valve disease
- Coronary artery disease
- Obesity; alcohol abuse
- Sleep-disordered breathing These conditions can lead to various pathological changes, including:
- RAAS activation
- Fibrotic and adipocyte signaling
- Atrial hypertrophy; cardiomyopathy
- Increased atrial ectopy (PACs)
If PACs are causing significant symptoms like palpitations, dizziness, or shortness of breath, lifestyle modifications should be tried first, including reducing caffeine, alcohol, and nicotine intake, managing stress, getting adequate sleep, and staying hydrated. For persistent symptomatic PACs, medications may be considered, including beta-blockers (such as metoprolol 25-100 mg twice daily) or calcium channel blockers (such as diltiazem 120-360 mg daily in divided doses) 1. These medications work by slowing electrical conduction through the heart and reducing the excitability of cardiac tissue. In rare cases where PACs trigger more serious arrhythmias or cause significant symptoms despite medication, catheter ablation might be considered. This procedure identifies and eliminates the abnormal electrical pathway causing the PACs. It's essential to note that while most PACs are harmless, frequent PACs may sometimes indicate underlying heart disease, so evaluation by a healthcare provider is recommended, particularly for new-onset or worsening symptoms 1.
From the Research
Premature Atrial Contractions (PACs)
- PACs occur in nearly all individuals and are typically asymptomatic, but can cause palpitations 2
- Frequent PACs are associated with an increased risk of developing atrial fibrillation 2
- Symptomatic PACs can be treated with beta blockers, and some patients may be candidates for ablation 2
Treatment and Management
- Beta blockers may help reduce PAC symptoms and improve long-term outcomes, with a significant reduction in mortality rates 3
- The effectiveness of beta blockers in reducing mortality rates was consistent in both high-burden and low-burden patients 3
- Calcium channel blockers and angiotensin receptor blockers may also be effective in reducing blood pressure, with no significant difference in efficacy compared to beta blockers 4
Associated Risks and Complications
- PACs are associated with an increased risk of atrial fibrillation, but the use of beta blockers does not appear to reduce this risk 3
- Persistent premature ventricular contractions (PVCs) are associated with underlying heart disease, and an echocardiogram can help detect this disease 2
- Reversible causes of PACs and PVCs, such as electrolyte abnormalities and hyperthyroidism, should be excluded before treatment 2