NCT04194632 · University of California, San Francisco
Right Ventricular Pacing in Pulmonary Arterial Hypertension
What this study is about
In pulmonary arterial hypertension (PAH), progressive pulmonary vascular remodeling leads to supraphysiologic right ventricular (RV) afterload. Pharmacologic trials have shown that aggressive upfront treatment reversing pulmonary vascular remodeling successfully increases RV function and improves survival. To date, however, there are no proven treatments that target RV contractile function.
View original scientific description
In pulmonary arterial hypertension (PAH), progressive pulmonary vascular remodeling leads to supraphysiologic right ventricular (RV) afterload. Pharmacologic trials have shown that aggressive upfront treatment reversing pulmonary vascular remodeling successfully increases RV function and improves survival. To date, however, there are no proven treatments that target RV contractile function. Echocardiographic studies of RV dysfunction in the setting of pressure overload have demonstrated intra and interventricular dyssynchrony even in the absence of overt right bundle branch block (RBBB). Electrophysiologic studies of patients with chronic thromboembolic disease (CTEPH) at the time of pulmonary endarterectomy have shown prolongation of action potential and slowed conduction in the right ventricle which has correlated with echocardiographic measures of dyssynchrony. Cardiac MRI measures of RV strain in patients with PAH demonstrated simultaneous initiation of RV and left ventricular (LV) contraction, but delayed peak RV strain suggesting that interventricular dyssynchrony is a mechanical rather than electrical phenomenon. Prior studies of RV dysfunction in an animal model, computer model, congenital heart disease, and CTEPH have suggested acute hemodynamic benefits of RV pacing. However, RV pacing has not been studied in patients with PAH. Furthermore, it remains unclear if pacing particular regions of the RV can achieve a hemodynamic benefit and what cost this hemodynamic improvement may incur with regards to myocardial energetics and wall stress. Therefore, the investigators propose to examine RV electrical activation in PAH, map the area of latest activation, and then evaluate the hemodynamic and energetic effects of RV pacing in these patients.
Interventions
PROCEDURE
Temporary right ventricular pacing
As described previously. Patients will undergo temporary pacing at the site of latest endocardial activation with measurement of hemodynamic effects.
Primary outcome measures
Change in contractility (Ees)
Time frame: During procedure. The measurement will be taken pre-RV pacing, with RV pacing, and 5 minutes after RV pacing. All catheters will then be removed and the study will be completed.
This is an invasive measure of the contractile strength of the right ventricle that is measured using pressure volume measurements from within the ventricle itself.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Patients referred for a clinically indicated right heart catheterization to either diagnose pulmonary arterial hypertension prior to initiating therapies or monitor response to ongoing therapies in patients with diagnosed pulmonary arterial hypertension.
- Patients with pulmonary arterial hypertension with or without significant right ventricular dysfunction as assessed by baseline echocardiography and standard of care right heart catheterization
- Functional class 2 or 3 symptoms
- Are able to undergo cardiac MRI, endocardial mapping, and pressure volume measurements
- English speaking
- All patients will be required to have evidence of right ventricular hypertrophy or conduction delay (QRS \> 130ms) on surface ECG
Exclusion criteria
- Preexisting left bundle branch block, current atrial fibrillation, or pacemaker/ defibrillators
- Functional class 4 symptoms
- Patients treated with parenteral or subcutaneous therapies for pulmonary hypertension
- Contraindication to right heart catheterization including significant thrombocytopenia (platelets \< 50,000), coagulopathy (INR \> 1.8), or pregnancy as determined by routine screening laboratory work
- Mean pulmonary artery pressure less than 25 mmHg as determined by the right heart catheterization on the day of the study procedure
- Pulmonary capillary wedge pressure greater than or equal to 15 mmHg as determined by the right heart catheterization on the day of the study procedure
- Severe tricuspid regurgitation as determined by baseline transthoracic echocardiogram.
- Left ventricular dysfunction (EF \< 50%) as determined by baseline transthoracic echocardiogram.
- Inability to complete cardiac MRI or transthoracic echocardiography
- Patients with confounding systemic disease specifically portopulmonary hypertension and scleroderma associated pulmonary hypertension
- Patients otherwise deemed not appropriate for the study as determined by the study investigators
Where
- San Francisco, California
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Sep 2, 2026 · Source of record for eligibility and locations