Why they did it
Since occult dilated cardiomyopathy (ODCM) is common in Doberman pinschers, these researchers were out to find a marker to help identify the condition as early as possible.
What they did
Using a combination of echocardiography, 24-hour Holter monitoring, and the NT-proBNP assay, researchers evaluated 155 asymptomatic Doberman pinschers for the presence of ODCM. ODCM was diagnosed based on a left ventricular internal dimension (LVID) between 38.8 mm to 43 mm normalized to weight in dogs weighing up to 55 kg, the presence of > 50 ventricular premature complexes, or both.
What they found
ODCM was diagnosed in nearly half (47%) of the Doberman pinshcers evaluated based on Holter monitor readings (31), echocardiographic evidence (17), or both criteria (25). An NT-proBNP concentration > 457 pmol/L successfully identified 45.2%, 76.5%, and 96% of these patients, respectively, with ODCM. The overall sensitivity and specificity of the combination Holter monitoring and pro-BNP test to detect ODCM was 94.5% and 87.8%, respectively, with an accuracy of 91%.
Disease status and NT-proBNP concentration were independently predictive of all-cause mortality. The median survival time of dogs with > 50 ventricular premature complexes (469 days), NT-proBNP concentration > 900 pmol/L (284 days), or ODCM (474 days) was significantly (P < 0.0001) shorter than those with < 50 ventricular premature complexes (1,743 days), NT-proBNP concentration < 900 pmol/L (1,743 days), or those without disease (1,743 days).
Use of the NT-proBNP assay in conjunction with a Holter monitor is the most accurate way to predict ODCM in Doberman pinschers. An elevated NT-proBNP concentration, > 50 ventricular premature complexes during Holter monitoring, or both indicate a greater than sevenfold likelihood for the presence of ODCM. An elevation in the NT-proBNP concentration in this breed would support the need for further testing such as echocardiography to evaluate for ODCM.
Singletary GE, Morris NA, O’Sullivan ML, et al. Prospective evaluation of NT-proBNP assay to detect occult dilated cardiomyopathy and predict survival in Doberman Pinschers. J Vet Intern Med 2012;26(6):1330-1336.