Can frequent premature atrial contractions be caused by tuberous sclerosis complex (TSC) with a TSC1 mutation?

Tuberous Sclerosis Complex and Premature Atrial Contractions

Association Between TSC and Cardiac Arrhythmias

Frequent premature atrial contractions could potentially be related to your TSC1 mutation, though cardiac rhabdomyomas are the more common cardiac manifestation of tuberous sclerosis complex.

• Cardiac involvement in TSC primarily manifests as cardiac rhabdomyomas, which are present in approximately two-thirds of newborns with TSC 1
• These rhabdomyomas are typically largest during the neonatal period and tend to regress with time 1
• Arrhythmias have been reported in patients with TSC-associated cardiac rhabdomyomas, occurring in approximately 20% of pediatric patients with these tumors 2

Cardiac Manifestations in TSC

• Cardiac rhabdomyomas can cause various complications including:

  • Heart failure (in some patients) 2
  • Arrhythmias (reported in clinical studies) 2
  • Conduction abnormalities that may persist even after regression of the tumors 3

• While premature atrial contractions (PACs) are not specifically mentioned in TSC diagnostic criteria, cardiac involvement in TSC can manifest beyond the typical rhabdomyomas 1, 4

Mechanism of Arrhythmias in TSC

• The TSC1 and TSC2 genes encode proteins (hamartin and tuberin) that form a complex inhibiting the mammalian target of rapamycin (mTOR) pathway 5
• Dysfunction of this pathway leads to abnormal cellular growth and proliferation in multiple organs 5
• This abnormal cellular growth could potentially affect cardiac conduction tissue, leading to arrhythmias such as PACs 3

Evaluation Recommendations

• If you have frequent PACs and TSC, consider:
  • Echocardiography to evaluate for the presence of cardiac rhabdomyomas or other structural abnormalities 2
  • 24-hour Holter monitoring to characterize the frequency and pattern of PACs 6
  • Evaluation for other potential causes of PACs, as they are common in the general population as well 6

Management Considerations

• Management should be guided by:

  • Severity of symptoms related to PACs 6
  • Presence of other cardiac abnormalities 1
  • Overall clinical picture including other TSC manifestations 4

• If PACs are causing significant symptoms:

  • Beta-blockers may be considered as first-line therapy for symptomatic patients 6
  • Regular cardiac follow-up is recommended for all TSC patients, particularly those with known cardiac involvement 4

Important Considerations

• TSC requires a multidisciplinary approach to management, with coordination between specialists in neurology, nephrology, cardiology, and other relevant disciplines 4
• Regular follow-up should occur at least annually with specialists relevant to your specific manifestations 4
• Transitions between pediatric and adult care should be carefully planned for patients with TSC 7

Conclusion

While the direct causation between TSC1 mutations and PACs is not definitively established in the literature, there is a plausible connection given the known cardiac involvement in TSC. A thorough cardiac evaluation is warranted to determine if your PACs are related to your TSC or if they represent an independent finding.