The Heart Rhythm Twins Study

NCT05866731 | Completed

• 1 other identifier: 21-35126
• Study Type: observational
• Target: 156
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Premature Ventricular Contraction; Premature Atrial Complex

Keywords

twin

Outcome Measures

Primary Outcomes (2)

• Frequency of premature atrial contractions (PACs)

  This will be measured using a wearable EKG monitor.

  Maximum of 2 weeks

• Frequency of premature ventricular contractions (PVCs)

  This will be measured using a wearable EKG monitor.

  Maximum of 2 weeks

Study Arms (2)

Identical twins

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.

Same-sex fraternal twins

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.

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

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.

You may qualify if:

• Identical or same-sex fraternal sets of twins
• English-speaking

You may not qualify if:

• Pregnancy
• Current anti-arrhythmic medication use (including beta blockers)
• Diagnosis of congenital heart disease
• Diagnosis of persistent or permanent atrial fibrillation
• Prior cardiac ablation

Sponsors & Collaborators

• University of California, San Francisco: lead

Study Sites (1)

University of California, San Francisco

San Francisco, California, 94143, United States

Location

Biospecimen

Retention: SAMPLES WITH DNA

Saliva samples

MeSH Terms

Conditions

Atrial Premature Complexes; Ventricular Premature Complexes

Condition Hierarchy (Ancestors)

Cardiac Complexes, Premature; Arrhythmias, Cardiac; Heart Diseases; Cardiovascular Diseases; Cardiac Conduction System Disease; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Study Officials

• Greg Marcus, MD, MAS

  University of California, San Francisco

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: May 10, 2023
• First Posted: May 19, 2023
• Study Start: March 22, 2022
• Primary Completion: March 16, 2025
• Study Completion: August 18, 2025
• Last Updated: March 9, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)