Abstract
BackgroundHeart murmurs are detected commonly in apparently healthy cats during routine physical examination, and Doppler echocardiography ultimately is required to identify the source of flow turbulence causing the murmur. However, in some cases, the origin of the murmur cannot be identified on echocardiographic examination, even by experienced clinicians. The application of gentle pressure with the ultrasound transducer against the chest wall of a cat can induce temporary narrowing of the mid‐right ventricular (RV) lumen, causing blood flow turbulence even in the absence of cardiac abnormalities.Objectives/HypothesesTo evaluate the effect of pressure of the ultrasound transducer against the chest wall of cats during echocardiography (provocative testing) on RV blood flow. The main hypothesis is that provocative testing can increase RV outflow velocity and cause flow turbulence. The second hypothesis is that the effect of this maneuver is independent of changes in heart rate during testing.AnimalsSixty‐one client‐owned, apparently healthy cats with heart murmurs on physical examination.MethodsRetrospective review of echocardiographic examinations of 723 cats presented for investigation of a heart murmur.ResultsOutflow systolic velocity increased from 1.05 ± 0.26 to 1.94 ± 0.51 m/s during provocative testing (P < .0001); no correlation was found between RV outflow peak velocity and heart rate during provocative testing (P = .34; r = 0.1237).Conclusions and Clinical RelevanceRight ventricular outflow tract obstruction and associated heart murmur can be iatrogenically induced in apparently healthy cats by increasing pressure on the right chest wall with an ultrasound probe.
Highlights
Heart murmurs are detected commonly in apparently healthy cats during physical examination, and the prevalence of heart disease in these patients varies from 16% to 77% depending on geographic location, examiners, and study methods.[1,2] The most common underlying cardiac abnormality observed in cats with incidentally detected murmurs is hypertrophic cardiomyopathy, reported in 15% to 62% of cases.[3-7]
Even Doppler echocardiography performed by experienced clinicians occasionally can fail to identify the origin of murmurs in cats, and failure to identify the cause of a murmur and classify it as either pathological or benign can lead to uncertain prognosis and unnecessary owner anxiety.[1,2]
Only patients that had blood flow turbulence in the right infundibular tract induced by gentle pressure to the chest wall with the ultrasound transducer during image acquisition of the right parasternal short axis view at the level of the heart base and that did not have any functional or structural abnormalities during echocardiographic examination were selected
Summary
Heart murmurs are detected commonly in apparently healthy cats during physical examination, and the prevalence of heart disease in these patients varies from 16% to 77% depending on geographic location, examiners, and study methods.[1,2] The most common underlying cardiac abnormality observed in cats with incidentally detected murmurs is hypertrophic cardiomyopathy, reported in 15% to 62% of cases.[3-7]. We have incidentally observed that applying gentle pressure with the ultrasound transducer to the right side of the chest wall of a cat can induce temporary narrowing of the mid-RV lumen, iatrogenically inducing DRVOTO and subsequently evoking blood flow turbulence. Our main objective was to evaluate the effect of increased pressure of the ultrasound transducer against the chest wall of apparently healthy cats during echocardiographic examination on RV outflow velocity. We hypothesized that such a maneuver would increase RV outflow velocity, resulting in blood flow turbulence in this anatomical area. We hypothesized that this effect is independent of changes in heart rate during this test
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
