In human medicine, the connection between the kidneys and the heart has been recognized and discussed for decades. Many hospitalized human patients have varying degrees of both heart and kidney insufficiency, which led medical specialists to realize that a primary problem with either the heart or the kidneys often resulted in injury to the other organ system. Recently, the phrase cardiorenal syndrome has been adopted to describe the complex interactions between the cardiovascular (heart and blood vessels) and renal (kidneys) systems.
What does this mean for dogs with kidney disease?
Veterinarians know that several health issues faced by dogs — including kidney disease, certain tick-transmitted diseases, snake bites, pyometra (infection of the uterus), gastric dilatation volvulus (aka GDV, which is the bloating and twisting of the stomach) and others — may result in damage to the heart. An international group of veterinary kidney and heart specialists believe dogs may experience a syndrome similar to human cardiorenal syndrome. Although it’s an area of veterinary interest that’s in its infancy, studies are already providing new insights into the relationships between the canine heart and kidneys.
Can acute kidney injury cause heart damage?
Veterinary researchers with the University of Bern in Switzerland evaluated 24 client-owned dogs with moderate to severe acute (sudden) kidney injury. Most of the dogs were diagnosed with leptospirosis, an infection caused by corkscrew-shaped bacteria. Heart evaluations included a physical exam, chest X-rays, echocardiography (ultrasound imaging of the heart), 24-hour Holter monitoring of heart rate and rhythm, and blood testing to detect a marker of heart damage (cardiac troponin I). Holter monitoring and blood work were repeated seven to 10 days after the initial exam.
The 24-hour heart rhythm recordings found 19 of the 24 dogs experienced an abnormal rhythm in which the ventricles (the two bottom chambers of the heart) contracted prematurely. Testing also found increased levels of cardiac troponin I, the marker of heart tissue injury, in 22 of the 24 dogs. Twenty dogs recovered following treatment for their condition and were discharged from the hospital.
The researchers acknowledged that leptospirosis can affect the heart, causing abnormal heart rhythm, increased markers of heart damage and inflammation of the heart muscle and its surrounding sac. Whether the heart issues seen in this study were due to leptospirosis or to kidney injury isn’t clear; however, researchers didn’t find an obvious association between the heart and leptospirosis. They concluded that abnormal heart rhythm and damage to the heart are common in dogs with acute kidney injury, similar to cardiorenal syndrome in people.
What does this study mean for your dog?
More research is needed — and is being done — to confirm and further describe the connections between canine kidneys and heart. For now, this study’s findings help support what veterinarians already know: treatment of acute kidney injury also needs to consider and address the likelihood of heart damage.