Below, please find links to all of the clinical trials involving cardiology. The studies include a multitude of information, including (but not limited to) the study’s purpose, benefits for participating, and financial incentive information. If you have any questions, please contact the individual outlined at the end of each trial summary.

Please visit the Cardiology service webpage at the Veterinary Medical Teaching Hospital (VMTH) if you would like to learn more about the amazing things that our veterinarians can do for you and your animal.


NEW! Heart Murmurs: Improving Ways to Measure Heart Function

Title: Evaluation of the efficacy of timolol ophthalmic suspension to transiently decreased heart rate and improve echocardiographic analysis in cats

Purpose of Study: Because of patient “nerves” (called sympathetic tone), many cats have elevated heart rates while they are in hospital, which makes important cardiac measurements difficult to obtain. Although timolol is used in pets and humans with glaucoma, this commonly used eye drop may also slightly decrease an already elevated heart rate. Therefore, we are investigating the use of timolol to help improve our ability to measure heart function using echocardiogram (cardiac ultrasound).

Participation Requirements: Requirements include patient’s that are free from respiratory disease (ex. feline asthma) and ocular disease, but have a heart murmur, and tolerate handling without sedation. An echocardiogram will be performed which requires the pet to lay on his/her side for about 15-30 minutes.

Initial Evaluation for Participation: All cats should be screened for the presence of a heart murmur, absence of history of cough or respiratory signs, and obvious ocular disease.

Procedures: A complete echocardiographic study will be completed as part of your normal work up by the Cardiology service at UC Davis. If we determine that your cat is eligible for the study and you agree to be involved in it, a small blood sample will be taken and saved for future genetic analysis. One drop of an ophthalmic medication called timolol will be instilled into the right eye of your pet. About 15-20 minutes later, a brief recheck echocardiogram will be performed.

Benefits: Although you are responsible for the cost of the initial Cardiology exam and echocardiogram, the study will cover for a significant portion of those costs (reducing the expense to approximately $125 compared to $450 or more), the administration of timolol and the brief recheck echocardiogram after the administration of this medication.

All cats with a heart murmur are generally recommended to be evaluated by a cardiologist to deterimine if they have significant heart disease. This study will provide a full cardiology report that you and your family veterinarian can use to assess your pets cardiac health at a significant cost reduction. We cannot promise any direct benefits to your cat or other animals from your taking part in this clinical trial; however, possible benefits include improved ability to diagnosed cardiac dysfunction by helping us obtain important measurements about heart function more accurately. This in turn will help us diagnose some heart diseases earlier, more accurately, and institute treatment (if warranted) sooner. If this trial is successful, these eye drops may transform the way feline heart hearts are routinely evaluated and help us better understand common heart diseases in cats (such as hypertrophic cardiomyopathy also known as HCM).

Owner Responsibilities: If you allow your cat to participate in this study, you will be responsible for the cost associated with the initial Cardiology exam and echocardiograph ($125), and alerting the Cardiology service of any cough, behavior changes, eye irritations, or medical concerns observed within 24 hours.

Contact: Eric Ontiveros, Stern Laboratory Coordinator ( or 530 -752-4892) to make an appointment

Printable Flyer (PDF)

Hypertrophic Cardiomyopathy: Understanding the Condition

Title: Biomarker Assessment of Feline Hypertrophic Cardiomyopathy

Purpose of Study: In human heart disease, traceable substances in the blood, referred to as biomarkers, are used to assess severity of a common heart disease called hypertrophic cardiomyopathy (HCM). Recent research identified biomarkers associated with inflammation that are elevated in HCM patients. Studies have also investigated biomarkers in cats, such as B-type natriuretic peptide (BNP), that correlate with the severity of heart disease. Only one previous study has attempted to identify the level of an inflammatory biomarker in cats with heart failure. Although the study identified elevated levels of this biomarker, there have been no multimarker studies using inflammatory biomarkers in feline HCM.

This study will compare concentrations of three individual inflammatory biomarkers and BNP in cats with and without HCM. The goal is to determine the ability of multiple biomarkers to identify and assess, and hopefully correlate to, the degree of heart disease in cats. Early identification of this disease will lead to earlier treatment and potentially prevention of the development of heart failure.

Participation Requirements: Cats diagnosed with hypertrophic cardiomyopathy but not currently on any medications.

Initial Evaluation for Participation: Cats must have a recent echocardiogram by a board-certified cardiologist that documents their current cardiac structure and function.

Procedures: If you agree to let your cat participate in this study, we will collect a blood sample from your cat.

Benefits: There is no charge for you to allow your cat to participate in this clinical trial. All costs associated with the blood analysis will be paid by the sponsor/department.

We cannot promise any benefits to your cat or other animals from your taking part in this clinical trial; however, possible benefits hope to define the relationship between inflammation and the severity of hypertrophic cardiomyopathy in cats.

Owner Responsibilities: If you allow your cat to participate in this study, you will be responsible to bring your cat in to the Veterinary Medical Teaching Hospital for the outlined procedures on your scheduled appointment (NOTE: Your cat’s participation will take approximately four (4) hours).

Contact: Dr. Karl Jandrey, DVM, MAS, DACVECC in the Veterinary Medical Teaching Hospital, Small Animal Emergency and Critical Care Service, at (530) 752-1393


NEW! Abnormal/Rapid Heartbeat (Ventricular Arrhythmia): Assessing Treatment

Title: Acute effects of sotalol on echocardiographic indices of ventricular function in dogs with ventricular tachyarrhythmias

Purpose: Sotalol is considered by most veterinary cardiologists to be one of the most effective and well-tolerated medications for longterm control of potentially life-threatening ventricular arrhythmias (abnormal and rapid heartbeats arising from the pumping chambers). Sotalol may decrease heart function (pumping ability) but it is currently unknown to what extent, if any, it does so. Therefore, the purpose of this clinical trial is to determine the effect of a single standard dose of sotalol on heart function and rhythm in dogs diagnosed with ventricular arrhythmias.

Participation Requirements: Dogs that have been diagnosed with a ventricular arrhythmia (abnormal and rapid heartbeats originating in the pumping chambers of the heart)

Initial Evaluation for Participation:  Dogs should be evaluated for the presence of ventricular tachyarrhythmias by a veterinarian. Dogs will be considered ineligible for the study if they weigh less than 10 kg (20 lbs), are already taking sotalol, are taking heart medications that affect heart function (e.g., pimobendan or beta-blockers), and if they are affected with significant kidney disease.

Procedures: Please note that no diagnostic test or therapeutic intervention will be withheld or delayed for any reason for the purposes of this study and no “experimental” tests or drugs will be used in this study.

If you agree to let your dog participate in this study, the following will happen:

  • Review of your dog’s medical history, medication history, and any clinical signs (symptoms) your dog may be experiencing with your dog’s attending clinician
  • Completion of a physical examination with particular attention paid to the cardiovascular system
  • Complete echocardiogram (cardiac ultrasound) without the use sedatives. Echocardiograms involve your dog being gently restrained while lying on their side and usually last 20-25 minutes.
  • Immediately following this echocardiogram, your dog will be administered a single standard dose (2 mg/kg) of sotalol by mouth after which your dog will be monitored in the cardiology service room or patient care ward by direct observation.
  • 2-4 hours after your dog received the sotalol medication (allows time for the drug to take effect), your dog will have the exact same echocardiogram performed, after which your dog’s participation in the clinical trial will be completed.
  • Blood collection (2 mL) to look for genetic mutations that may cause a lack of response to the drug.

It is important to understand that this study is not a therapeutic trial; it is a study assessing the acute effects of sotalol on heart function and rhythm following a single dose of the sotalol medication. At the conclusion of your dog’s visit to the VMTH the veterinarian in charge of your dog’s care (attending clinician) may or may not recommend that your dog be sent home on the sotalol medication for longterm therapy. It is possible that a more thorough evaluation of your dog’s heart rhythm with a 24-hour Holter (ECG/”EKG”) monitor is warranted to help determine if long-term therapy is necessary. Please understand that not all ventricular arrhythmias require a long-term antiarrhythmic medication.

Benefits: It is considered standard-of-care to have an echocardiogram (heart ultrasound) performed in dogs with ventricular arrhythmias. If you agree to have your dog participate in this study, the study will cover $159 of the echocardiogram (you will need to pay the remaining $171). The remainder of the cost of your dog’s visit (to be discussed with the attending clinician) will be your responsibility. If adverse events occur directly as a result of the study and your dog requires further care (e.g., hospitalization, monitoring, treatment(s)/medication(s), etc.), the clinical cardiology service will cover up to $3,000 of your dogs care.

We cannot promise any benefits to your dog or other animals from your taking part in this clinical trial; however, possible benefits include allowing us to better guide medical care for your dog and future dogs affected with arrhythmias.

Owner Responsibilities: You will be responsible for bringing your dog in for your scheduled appointment (which will last approximately ½ of the day or 4 hours), covering the $171 of the first echocardiogram, the appointment fee ($140) and whatever else is discussed between you and the attending clinician regarding the management of your dog’s heart disease.

Contact: For questions or any research-related injuries or adverse events, please contact the Principal Investigator, Dr. Lance C. Visser, DVM, MS, DACVIM (Cardiology) at (616) 633-6231 or

To schedule an appointment, please contact Pam McInnis at

Printable Flyer (PDF)

Pulmonary Hypertension: Understanding the Genetics

Title: The Role of Genetics in Canine Pulmonary Hypertension and the Response to Standard Treatment with Sildenafil

Purpose: We are investigating the role of a common canine genetic variant on the condition of pulmonary hypertension. This genetic variant is being evaluated to see if it impacts the severity of disease or the response to the oral medication, sildenafil citrate, the most commonly used drug for the treatment of this condition. Information provided by this study will provide better guidelines for the treatment of dogs with pulmonary hypertension.

Participation Requirements: Dogs diagnosed with pulmonary hypertension

Initial Evaluation for Participation: 

  • Diagnosis of pulmonary hypertension confirmed by a complete echocardiographic study that was done by the UC Davis VMTH Cardiology service; and,
  • A recommendation from the veterinarian to give oral sildenafil for treatment of the condition.

Procedures: If you agree to be involved in this study:

  • Initial visit: We will collect a small blood sample and then perform a non-invasive assessment of blood flow, which will involve shaving a small area (the size of a postage stamp). You will be asked to give the sildenafil orally to your dog as prescribed by your veterinarian.
  • 25-35 days later: We need you to return to the hospital while your pet is receiving the medication to have the echocardiogram, blood sampling and shaved patch for vascular function assessment performed again.
  • You (the owner) will be asked to fill out a brief health questionnaire for your dog at each visit.

Benefits: There is no charge for you to allow your dog to participate in this clinical trial. The study will cover all costs associated with the diagnostic tests, examination fees and the 1-month supply of sildenafil medication. You will be responsible for covering costs associated with any adverse effects that your dog experiences secondary to the prescribed medication.

We cannot promise any benefits to your dog or other animals from your taking part in this clinical trial; however, possible benefits include better understanding of the disease process and mechanisms for predicting patients response to medical therapy.

Owner Responsibilities: You will be asked to complete two brief questionnaires (one at each visit), administer all prescribed medications for at least 30 days, and return while your pet is receiving this medication for a reevaluation appointment at the end of the 30-day period.

Contact: For more information, please contact Dr. Joshua Stern at or 530-752-2475