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Page 22 of 24 Rao. Vessel Plus 2022;6:22 https://dx.doi.org/10.20517/2574-1209.2021.105

primary cyanotic CHD has not been corrected. If the shunt is large with the increased pulmonary flow, the
cyanosis is mild or not clinically detectable, and such patients will have mid-diastolic flow rumble at the
apex. The physical examination, chest X-ray, ECG, and echo-Doppler studies will demonstrate the primary
cardiac defect.

Other causes of continuous murmur
Frequent etiologies of continuous murmur were reviewed in the preceding section. Less frequent causes of
continuous murmur [5,25] are listed in (Table 9; bottom). These include: aorto-pulmonary window; truncus
arteriosus; hemi truncus; multiple aorto-pulmonary collateral arteries in children with tetralogy of Fallot;
rupture of sinus of Valsalva aneurysm; coronary arterio-venous fistula; pulmonary arterio-venous fistula;
peripheral PA stenosis; aortic coarctation, obstructed venous return, and cervical arteriovenous
malformation. Review of the clinical features and findings in chest roentgenograms and echo-Doppler
studies are helpful in identifying these rare causes of continuous murmur; these were detailed elsewhere
[5]
for the interested reader.

SUMMARY AND CONCLUSIONS
Cardiac murmur is commonly heard on auscultation. Murmur is the frequent reason for the recognition of
heart disease in children (with the exception of neonates). Mastery of skills of auscultation acquired by
training and experience is important in diagnosing the causes of cardiac murmurs. Cardiac patient
simulators and computer-assisted training methods have been used to educate students and residents; these
methods should supplement bedside acquisition of auscultatory skills under the supervision of experienced
clinicians and not become primary modes of training of our emerging physician pool. Murmurs are
classified into systolic, diastolic, and continuous types. The systolic murmurs are further divided into
ejection systolic and holosystolic murmurs. The more common etiologies of ejection systolic murmurs are
AS, PS, ASD, coarctation of the aorta, and functional heart murmurs. The causes of holosystolic murmurs
are VSD, MR, and TR. The diastolic murmurs are classified into early, mid and late (or presystolic) diastolic
murmurs. The early diastolic murmurs are caused by AR, PR, and pulmonary hypertension. Mid-diastolic
murmurs are produced by increased flow across the mitral valve (secondary to large shunts across a VSD or
PDA or moderate to severe MR) or high flow via the tricuspid valve (secondary to ASD, partial or total
anomalous pulmonary venous connection or moderate to severe TR). Other causes are Carey-Coombs
murmur of rheumatic fever, Austin-Flint murmur of AR, and stenosis of the AV valves. The presystolic
murmurs are produced by stenosis of the mitral or tricuspid valve and atrial myxoma. The continuous
murmurs are more commonly produced by PDA, venous hum, or aorto-pulmonary shunt procedures.
There are many other less common causes. Careful auscultation and other findings in history, physical
examination, chest roentgenogram, and ECG will frequently help come up with an accurate diagnosis.
Echo-Doppler studies are valuable and confirmatory in making the diagnosis, in quantifying the problem,
and are very useful in directing the type of and timing of management.

DECLARATIONS
Acknowledgments
The author wishes to thank numerous patients (and their parents) whom the author had the privilege to
examine at multiple institutions over the last five decades. The experience so gained resulted in formulating
this review.

Authors’ contributions
The author contributed solely to the article.