Cardiology Case Study
Successful Treatment of a Rare Cardiac Tumor

By Merrilee Small, DVM, DACVIM (Cardiology)
Summer 2017

Patient Name: Walle

Age:  7-year-old MN Boxer

Walle is a seven-year-old neutered male Boxer dog initially presented to our Emergency/Critical Care services on 12/26/16 for acute onset vomiting, diarrhea, and weakness. He was ambulatory but dull on presentation. He was evaluated by Merrilee Small, DVM, DACVIM (Cardiology), who found WHT 25.7kg/56.5#, HR 180bpm, RR 60bpm, Temp 97.9, muffled heart sounds, and oscillometric BP 54mmHg mean. FAST thoracic ultrasound revealed a moderate amount of pericardial effusion with evidence of cardiac tamponade and a mass effect near the heart. A FAST revealed scant free fluid, edematous gall bladder wall, and no obvious abnormalities on the spleen. Thoracic radiographs revealed a "tall" cardiac silhouette, prominent caudal vena cava, and no evidence of metastasis. Significant pericardial effusion was confirmed, and a moderate-sized echoic mass was identified at the heart base adjacent to the bifurcation of the pulmonary arteries, presumed to originate from the base of the heart although right atrial origin was also considered. Other workup included CBC (Hct 47%), Chemistry (BUN 28mg/dL, Creat 1.9mg/dL, ALT 220U/L), PT/PTT (16.5/98.1 seconds), and Cardiac Troponin (I 0.5ng/dL, N < 0.2ng/dL)      
Pericardiocentesis was performed, and a small amount of non-clotting hemorrhagic effusion was obtained. Following centesis, the pericardial sac was noted to be essentially evacuated and cardiac filling improved. A moderate amount of pleural effusion was then identified, likely leaked from the pericardial space. Referral for further investigation of the mass was discussed and deferred at the time. Yunnan Baiyao (1 capsule every 12 hours) and I'm-Yunity (2,400mg/day) were recommended, and the Yunnan Baiyao was implemented.
Dr. Small reevaluated Walle on 1/3/17 and 2/16/17. No pericardial, pleural, or abdominal fluid was noted, and the cardiac mass appeared unchanged. Walle was released with instructions to have him evaluated promptly if signs recurred.
Walle presented to the ER Service on 6/21/17 following an episode of acute collapse, and a large volume of pericardial fluid with echoic material suggestive of blood clots was identified. Pericardiocentesis was again performed and 240ml nonclotting hemorrhagic effusion was obtained.
He was evaluated on 7/10/17 by the Cardiology and Soft Tissue Surgery services at North Carolina State University, where a moderate-sized heart base mass was confirmed and observed to somewhat compress the right proximal pulmonary artery. He underwent thoracoscopic subtotal pericardectomy the next day. Histopathology of the pericardium revealed moderate arteriovenous hyperplasia with wall thickening and moderate parietal mesothelial erosion with mild mesothelial hypertrophy, consistent with chronic effusion. There was no evidence of metastatic disease. The heart base mass is most likely a chemodectoma-a benign, slow-growing tumor that can be associated with effusive processes.
Since the procedure, Walle is a new dog! He is scheduled to undergo a course of stereotactic radiation therapy in September in hopes of reducing the tumor mass to prevent future compromise of thoracic structures.  

Discussion:  Accumulation of pericardial effusion can result from neoplastic and non-neoplastic disease processes. Unless a cardiac mass is identified on ultrasound, achieving a definitive diagnosis can be challenging. Most are hemorrhagic effusions, and fluid analysis rarely provides diagnostic information. Cardiac Troponin-I has been shown to be elevated more commonly when neoplasia is present1. The most common cardiac neoplasms are hemangiosarcoma and heart base masses (typically neuroendocrine in origin). The location determined by ultrasound is essentially diagnostic. Hemangiosarcomas typically arise from the right atrium/auricular appendage. Sadly, a prognosis of cardiac hemangiosarcoma is poor, with a median survival of 11 days with no adjunctive therapy and two to six months with chemotherapy +/- surgery2,3.
Chemodectomas typically arise at the base of the heart between the proximal aorta and pulmonary artery. They are typically benign and slow growing, only leading to problems when they become large enough to compress cardiothoracic structures or, as in Walle's case, cause pericardial effusion. The clinical course of chemodectomas is unpredictable. In symptomatic patients, pericardectomy can resolve acute signs associated with tamponade. If the patient is large enough, minimally invasive thoracoscopic pericardectomy is possible (and available at The COVE). Stereotactic radiation entails only 4-5 consecutive days of treatment and side effects are minimal. SRT has been shown to improve survival of patients with clinically significant heart base masses4. In a series of 15 dogs, some with very large chemodectomas, many patients improved clinically and the median survival was 476 days5.


  1. Chun R et al. Comparison of plasma cardiac troponin I concentrations among dogs with cardiac hemangiosarcoma, noncardiac hemangiosarcoma, other neoplasms, and pericardial effusion of nonhemangiosarcoma origin. J Am Vet Med Assoc. 2010 October; 237(7):806-11.
  2. Mullin C et al. Doxorubicin chemotherapy for presumptive cardiac hemangiosarcoma in dogs. Vet Comp Oncol. December 2016;14(4):e171-e183.
  3. Weisse C et al. Survival times in dogs with right atrial hemangiosarcoma treated by means of surgical resection with or without adjuvant chemotherapy: 23 cases (1986-2000). J Am Vet Med Assoc. 2005 February; 226(4):575-9.
  4. Magestro L et al. Early experiences with a three-fraction stereotactic radiation therapy protocol in four dogs with presumed chemodectomas. Proceedings Veterinary Cancer Society 2016
  5. Round Table Discussion of Cardiac Tumors. Proceedings ACVIM Forum 2016.
Danielle Russ, LVT, BS, BA, AS, will be speaking at  CVC-Central on August 28, 2017 in Kansas City. Her popular lectures are always packed with valuable practice management information. This year, topics include:
  • Constructive Criticism: Fact or Fiction?
  • Being Fearless In Management
  • Needs Care, No $$$... What Now?
For more information, visit:  thecvc.com/cvc-kansas-city
Tech Tip
Did You Know?
Pericardial Effusion: The Great Imitator

Recognizing Red Flags on Physical Exam

Patients with pericardial effusion can present with symptoms similar to a number of other conditions. It is often unseen, and can easily be misdiagnosed. Some important cardio-specific clues can be caught on the physical exam and initial diagnostic workup, if you pay close attention:
  • Weakness / Lethargy / Collapse
  • Muffled heart sounds
  • Jugular vein distension
  • Abdominal distension
  • Pulsus paradoxus: alternating strong and thready pulses coinciding with respiration (inspiration=thready, expiration=strong)
  • Enlarged, globoid heart on thoracic radiographs
  • Electrical alternans (ECG): alternating tall and short R-waves within each heart beat due to heart swinging in the pericardium
The COVE now offers Minimally Invasive Surgery

In cases where surgery is required, we always look for options that will cause the least amount of pain and provide the quickest recovery option for our patients. In a minimally invasive procedure, small incisions are made and are used as passageways, for a "laparoscope" or "endoscope," which are tiny fiber optic video cameras. Working from the images provided from the scope, special instruments are then passed through other openings and operated by remote-control to perform the necessary procedure.
Benefits to your patients:
  • Small incisions
  • Quicker recovery time
  • Less pain
  • Less scarring
  • Lower risk of infection
  • Reduced blood loss
We offer MIS for:
  • Laparoscopy:Abdominal and pelvic surgery
  • Thoracoscopy: 
    Lung/chest surgery
  • Arthroscopy: Joint surgery
Would you like to learn more? Please call us anytime!
Jacqueline Nobles, DVM, DACVECC
On board and ready to serve you and your emergency and critical care patients

A Monroeville, Alabama native, Dr. Nobles has started and expanded two large specialty hospitals in Oklahoma and Florida. She is honored to join The COVE and continue to serve our exceptional community of veterinarians and pets. We are confident you will enjoy her expertise, kindness, and steadfast dedication to patient and client care.

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