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NCT Number: NCT07707583

Heart Rate Variability and Medication Adherence in Resistant Hypertension

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.

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Key information

Conditions

Resistant Hypertension Autonomic Nervous System Behavior Health Behavior Medication Adherence Patient Acceptance of Health Care Patient Compliance Treatment Adherence and Compliance

Age range

18 year–75 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Nemocnice AGEL Třinec-Podlesí a.s.

Třinec, Moravian-Silesian Region, 739 61, Czechia

Location contact

Jan Alexander Mohr, MD

CONTACT

[email protected]

+420 724 173 927

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Heart rate variability recording (Polar H10) ·

Diagnostic Test

Short-term (10-15 min) seated HRV; time-domain (SDNN, RMSSD, pNN50) and frequency-domain (LF, HF, LF/HF) parameters.

Therapeutic drug monitoring (antihypertensive drug levels)

Diagnostic Test

Single blood draw measuring antihypertensive drug levels; defines adherent vs non-adherent status.

Questionnaires (MARS-CZ, PHQ-9, SF-36, IPAQ)

Other

Self-completed instruments assessing medication adherence, mood, quality of life, and physical activity.

Primary outcomes

  1. 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.

Secondary outcomes

  1. 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.

  2. 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.

  3. 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).

Study contacts

Contact information is provided by the study sponsor or research team.

Jan Alexander Mohr, MD

CONTACT

[email protected]

+420724173927

Sponsors and collaborators

Lead sponsor

Nemocnice AGEL Trinec-Podlesi a.s.

Other

Collaborators

  • Masaryk University

Registry information

Official study title

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

Acronym: HRV-HYP-1

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Jul 16, 2026
Registry last updated
Jul 16, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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