An observational study in Premature Atrial Complex and Premature Ventricular Contraction, sponsored by University of California, San Francisco. Completed at 1 site in United States. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-03-09.
Sponsored by University of California, San Francisco · Observational
Premature atrial contractions (PACs) and premature ventricular contractions (PVCs) are observed in the majority of individuals monitored for more than a few hours. Although the clinical course of PACs and PVCs is usually benign, it has been described that high PAC or PVC frequency causes various comorbidities and worsens outcomes in different patient groups. For example, PACs can initiate episodes of atrial fibrillation, and PAC count is highly specific in predicting diagnosis of incident atrial fibrillation. Increasing PVC frequencies are an important predictor of incident heart failure.
While conventional wisdom dictates that common environmental exposures determine PAC and PVC frequencies, this has not born out in rigorous studies. Whether PAC and PVC frequencies may have genetic underpinnings remains unknown.
Comparisons between identical twins and fraternal twins can provide estimates of heritability. Fraternal twins are an ideal control because, like identical twins, they share a womb, have the same birthday, and their environment while growing up are as similar as between identical twins. However, while identical twins share approximately 100% of the same inherited DNA, fraternal twins share, on average, about 50%. By monitoring identical and fraternal twins with portable electrocardiograms (ECGs), we will be able to count the PACs and PVCs over a consecutive timespan to describe the familial aggregation of these complexes. This, to our knowledge, would be the first study to compare PAC and PVC frequencies in identical and same-sex fraternal twins, providing the first assessment of how genetical inheritance may influence cardiac ectopy burdens.
28 studies on the registry are indexed under Atrial Premature Complexes; 6 are open to participants now.
This study's enrollment of 156 is below the median of 229 across 14 observational studies indexed under Atrial Premature Complexes.
Browse Atrial Premature Complexes studies →University of California, San Francisco is the lead sponsor of 2,169 studies on the registry; 372 are open to participants now.
Of its 267 completed or terminated interventional studies of FDA-regulated products, 202 (76%) have results posted.
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Same-sex sets of twins from anywhere in the world can enroll, as all study procedures can be done remotely. Both twins must enroll to participate.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
60 identical twins (30 sets) will be enrolled. Participants will answer 15-20 minutes of questionnaires on demographics, lifestyle, medical history, and family history over Zoom or the phone with a study coordinator. Participants will then be mailed an iRhythm Zio XT heart rhythm monitor, or EKG, to apply and wear for a maximum of 2 weeks, as well as a DNA Genotek saliva collection kit to collect a small saliva sample. Participants will return the monitor and saliva sample to the study team, and will be reimbursed upon return. The study team is also requesting photo validation to verify twin status.
60 same-sex fraternal twins (30 sets) will be enrolled. Participants will answer 15-20 minutes of questionnaires on demographics, lifestyle, medical history, and family history over Zoom or the phone with a study coordinator. Participants will then be mailed an iRhythm Zio XT heart rhythm monitor, or EKG, to apply and wear for a maximum of 2 weeks, as well as a DNA Genotek saliva collection kit to collect a small saliva sample. Participants will return the monitor and saliva sample to the study team, and will be reimbursed upon return. The study team is also requesting photo validation to verify twin status.
Frequency of premature atrial contractions (PACs)
This will be measured using a wearable EKG monitor.
Time frame: Maximum of 2 weeks
Frequency of premature ventricular contractions (PVCs)
This will be measured using a wearable EKG monitor.
Time frame: Maximum of 2 weeks
Plan to share: No
No publications or documents are linked to this record.
Ran from Mar 2022 to primary completion in Mar 2025, 35 months.
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This study is completed, as verified in Mar 2026. You cannot join it, but the record below documents what was studied.
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