Marinus S M, van Engelen H, Szatmári V
Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
J Vet Intern Med. 2017 May;31(3):661-667. doi: 10.1111/jvim.14667. Epub 2017 Mar 18.
Differentiating innocent cardiac murmurs from murmurs caused by congenital cardiac anomalies can be challenging with auscultation alone in asymptomatic puppies.
Plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentrations and phonocardiograms recorded by an electronic stethoscope can differentiate innocent from pathologic cardiac murmurs.
A total of 186 client-owned asymptomatic dogs: 135 Cairn Terriers (age: 45-124 days), 20 adult Cairn Terriers (age: 7.5 months to 13.5 years), and 31 puppies of various breeds (age: 29-396 days).
Study design is a cross-sectional survey. Each dog was auscultated, and when a cardiac murmur was heard, a phonocardiogram was recorded and an echocardiogram was performed. Plasma NT-proBNP concentrations were measured by a single laboratory by an ELISA.
No significant (P = .41) difference in plasma NT-proBNP levels was found between puppies without a murmur and puppies with an innocent murmur (median 300 versus 326 pmol/L), and between clinically healthy adult Cairn Terriers and Cairn Terrier puppies. Plasma NT-proBNP levels in puppies with a congenital heart disease were significantly (P < .001) higher than those in puppies with innocent murmurs (median 1,102 versus 326 pmol/L). However, some puppies with severe pulmonic stenosis did not have increased plasma NT-proBNP levels. On phonocardiograms, innocent murmurs had a significantly (P < .001) shorter "murmur-to-systole duration ratio" than the abnormal ones (median 66 versus 100%). The "murmur-to-S1 (first cardiac sound) amplitude ratio" was significantly (P < .001) lower of the innocent murmurs compared with that of the abnormal ones (median 16 versus 58 %).
Plasma NT-proBNP concentrations within the reference range do not rule out a congenital cardiac anomaly. Murmurs longer than 80% of the systole are most likely abnormal, whereas murmurs shorter than that could be either innocent or pathologic.
仅通过听诊来区分无症状幼犬的生理性心脏杂音和先天性心脏异常引起的杂音具有挑战性。
血浆N末端B型脑钠肽（NT-proBNP）浓度以及电子听诊器记录的心音图能够区分生理性和病理性心脏杂音。
总共186只客户拥有的无症状犬：135只凯恩梗犬（年龄：45 - 124天），20只成年凯恩梗犬（年龄：7.5个月至13.5岁），以及31只不同品种的幼犬（年龄：29 - 396天）。
研究设计为横断面调查。对每只犬进行听诊，当听到心脏杂音时，记录心音图并进行超声心动图检查。血浆NT-proBNP浓度由单个实验室通过酶联免疫吸附测定法进行测量。
无杂音的幼犬与生理性杂音的幼犬之间（中位数分别为300与326 pmol/L），以及临床健康的成年凯恩梗犬与凯恩梗幼犬之间，血浆NT-proBNP水平无显著差异（P = 0.41）。患有先天性心脏病的幼犬血浆NT-proBNP水平显著高于生理性杂音的幼犬（P < 0.001，中位数分别为1102与326 pmol/L）。然而，一些患有严重肺动脉狭窄的幼犬血浆NT-proBNP水平并未升高。在心音图上，生理性杂音的“杂音与收缩期持续时间比”显著短于异常杂音（P < 0.001，中位数分别为66%与100%）。与异常杂音相比，生理性杂音的“杂音与第一心音（S1）振幅比”显著更低（P < 0.001，中位数分别为16与58%）。
参考范围内的血浆NT-proBNP浓度不能排除先天性心脏异常。持续时间超过收缩期80%的杂音很可能是异常的，而短于此的杂音可能是生理性的或病理性的。
