Are Most People Symptomatic from PACs?
No, most people with premature atrial contractions (PACs) are asymptomatic. PACs occur in nearly all individuals but typically do not cause symptoms 1.
Symptom Profile
The ACC/AHA/ESC guidelines clearly state that patients with paroxysmal arrhythmias, including premature beats, are most often asymptomatic at the time of evaluation 2, 3. When symptoms do occur, they manifest as:
- Pauses or nonconducted beats followed by a sensation of a strong heartbeat
- Irregularities in heart rhythm or palpitations
- Less commonly: fatigue, lightheadedness, chest discomfort, or dyspnea 2, 3
Clinical Context and Prevalence
While PACs are nearly universal in the population 1, the vast majority remain clinically silent. In pediatric populations with excessive PACs (>50 per 24 hours), studies demonstrate that these remain asymptomatic in the overwhelming majority of cases 4. Among 343 children with numerous PACs, none developed cardiac symptoms during follow-up, reinforcing the benign symptomatic profile.
Important Clinical Caveat
Although typically asymptomatic, PACs are no longer considered entirely benign from a prognostic standpoint. Recent evidence shows that frequent PACs are associated with:
- Increased risk of developing atrial fibrillation 1, 5
- Potential for atrial cardiomyopathy 5
- Adverse atrial remodeling 6
- Increased all-cause mortality 5
These associations exist independently of whether patients experience symptoms, meaning asymptomatic PACs can still carry clinical significance 5.
Clinical Approach
When PACs are detected:
- Symptomatic patients warrant evaluation for reversible causes (electrolyte abnormalities, hyperthyroidism) and may benefit from beta blockers or, in select cases, ablation 1
- Asymptomatic patients with frequent PACs require risk stratification for future atrial fibrillation rather than dismissal as benign, particularly if PAC burden is high or originates from the lateral left atrium 6
The key distinction is that lack of symptoms does not equate to lack of clinical importance in the modern understanding of PACs.