Heart Rate Variability and Medication Adherence in Resistant Hypertension (HRV-HYP-1)

July 13, 2026 updated by: Matej Pekar, MD, PhD, Nemocnice AGEL Trinec-Podlesi a.s.

Eart Rate Variability, Medication Adherence, and Blood Pressure Control in Resistant Hypertension: A Cross-Sectional Study

This single-center, cross-sectional observational study examines the relationship between adherence to antihypertensive therapy - verified objectively by therapeutic drug monitoring (TDM) - and heart rate variability (HRV) in patients with resistant hypertension. Patients are recruited opportunistically, in a nurse-led manner, in a one-day-care cardiology unit, and undergo a single examination: a short-term HRV recording (Polar H10), a single blood draw for antihypertensive drug levels, office blood pressure, and self-completed questionnaires. There is no follow-up.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Non-adherence to antihypertensive medication is a major cause of apparently resistant hypertension and confounds interpretation of autonomic measures. HRV is a non-invasive index of autonomic cardiac regulation and is systematically influenced by antihypertensive drugs. The study tests whether TDM-verified intake of antihypertensives is reflected in HRV parameters, and whether HRV can serve as a complementary marker of adherence. Adherence is determined by TDM (the objective gold standard); a self-report questionnaire (MARS-CZ) is collected as a secondary, descriptive measure. HRV is recorded for 10-15 minutes seated, before sedation and before heparin/contrast; the blood sample is drawn before heparin/contrast, with the time of last dose recorded. Time-domain (SDNN, RMSSD, pNN50) and frequency-domain (LF, HF, LF/HF) HRV parameters are analysed. Approximately 100-200 patients are planned for enrolment. It does not interfere with the patient's planned cardiac procedure; the one-day-care unit is the recruitment venue only.

Study Type

Observational

Enrollment (Estimated)

150

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Czechia
    • Moravian-Silesian Region
      • Třinec, Moravian-Silesian Region, Czechia, 739 61
        • Nemocnice AGEL Třinec-Podlesí a.s.
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Adults (18-75 years) with essential hypertension treated with at least three antihypertensive drugs of different classes, including at least one diuretic (resistant hypertension), and in sinus rhythm. Participants are identified and recruited opportunistically, in a nurse-led manner, among patients attending a one-day-care cardiology unit at a single center.

Description

Inclusion Criteria:

  • Age 18-75 years with diagnosed essential hypertension
  • Treated with ≥3 antihypertensive drugs of different classes, including ≥1 diuretic (resistant hypertension)
  • Sinus rhythm
  • Able to give informed consent and understand Czech

Exclusion Criteria:

  • Absence of sinus rhythm: atrial fibrillation/flutter, ventricular arrhythmias, higher-degree AV block, pacemaker/ICD with sustained pacing, sustained SVT, or significant ectopy
  • Secondary hypertension
  • Pregnancy or breastfeeding
  • Cognitive impairment precluding informed consent

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Resistant hypertension (≥3 antihypertensives incl. diuretic, sinus rhythm)
Single cohort analysed by adherence status defined by TDM: adherent vs non-adherent.
Diagnostic test: Heart rate variability recording (Polar H10) ·
Short-term (10-15 min) seated HRV; time-domain (SDNN, RMSSD, pNN50) and frequency-domain (LF, HF, LF/HF) parameters.
Diagnostic test: Therapeutic drug monitoring (antihypertensive drug levels)
Single blood draw measuring antihypertensive drug levels; defines adherent vs non-adherent status.
Other: Questionnaires (MARS-CZ, PHQ-9, SF-36, IPAQ)
Self-completed instruments assessing medication adherence, mood, quality of life, and physical activity.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Heart rate variability parameters by TDM-defined adherence
Time Frame: At the single study visit (Day 1)
Time-domain (SDNN, RMSSD, pNN50) and frequency-domain (LF, HF, LF/HF ratio) HRV parameters from a short-term seated recording, compared between TDM-adherent and TDM-non-adherent patients.
At the single study visit (Day 1)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Heart rate variability in relation to office blood-pressure control
Time Frame: At the single study visit (Day 1)
Association between HRV parameters and office blood pressure measured seated immediately before the HRV recording.
At the single study visit (Day 1)
Questionnaire scores in relation to adherence and HRV
Time Frame: At the single study visit (Day 1)
Scores of MARS-CZ (adherence), PHQ-9 (mood), SF-36 (quality of life), and IPAQ (physical activity) examined against TDM-defined adherence and HRV parameters.
At the single study visit (Day 1)
Prevalence of non-adherence by therapeutic drug monitoring
Time Frame: At the single study visit (Day 1)
Proportion of patients classified as non-adherent to antihypertensive therapy based on TDM (absent or subtherapeutic drug levels).
At the single study visit (Day 1)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Nemocnice AGEL Trinec-Podlesi a.s.

Collaborators

Masaryk University

Investigators

  • Principal Investigator: Jan Alexander Mohr, MD, Nemocnice AGEL Třinec-Podlesí a.s.
  • Study Director: Matej Pekar, MD, PhD, Nemocnice AGEL Třinec-Podlesí a.s.

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

July 20, 2026

Primary Completion (Estimated)

July 20, 2027

Study Completion (Estimated)

December 31, 2027

Study Registration Dates

First Submitted

July 13, 2026

First Submitted That Met QC Criteria

July 13, 2026

First Posted (Actual)

July 16, 2026

Study Record Updates

Last Update Posted (Actual)

July 16, 2026

Last Update Submitted That Met QC Criteria

July 13, 2026

Last Verified

July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • HRV-HYP-1
  • EK 29/25 (Other Identifier: Ethics Committee, AGEL Třinec-Podlesí Hospital)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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