Article Text
PDF
Statistics from Altmetric.com
Clinical introduction
A young man was admitted for recurrence of acute myeloblastic leukaemia. On examination, blood pressure was 120/78 mm Hg. Cardiac auscultation revealed a soft precordial continuous murmur with normal P2. ECG revealed non-specific intraventricular block. A transthoracic echocardiogram (TTE) demonstrated normal chamber size with mild global left ventricular hypokinesis (ejection fraction (EF) 52%). On apical four-chamber view with colour Doppler, low velocity flow was demonstrated across the interventricular septum (online supplemental video 1). Parasternal short-axis colour Doppler documented abnormal systolic retrograde flow (toward the transducer) into the main pulmonary artery (MPA). Pulse Doppler located just distal to the pulmonary valve revealed that both the systolic and diastolic blood flow were toward the transducer. An ECG and TTE are shown in figure 1.
Supplementary video
Baseline investigations. (A) ECG. (B) Transthoracic echocardiogram (TTE): apical four-chamber view with colour Doppler. (C) TTE: parasternal short-axis view. (D) Pulsed Doppler of flow adjacent to the pulmonary artery (PA). AO, aorta.
Question
Which of the following is the most likely cause of precordial continuous murmur?
Persistent ductus arteriosus (PDA).
Raptured sinus of Valsalva aneurysm into the MPA.
Coronary artery fistula communicating with the pulmonary artery.
Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA).
ANSWER: D
All the above answers can cause persistent shunt into pulmonary artery and precordial continuous murmur. Absence of peripheral vessel sign, normal heart size and P2 sound did not support the diagnosis of PDA. Raptured sinus of Valsalva aneurysm into the MPA usually caused acute onset of congestive cardiac failure with acute aortic regurgitation. Prominent interventricular septal blood signal visualised by colour Doppler indicated communicating collateral vessels, which was not seen in patients with coronary–pulmonary fistula.
CT coronary angiography was performed and revealed that left main coronary artery originated from the left posterior lateral aspect of the MPA (figure 2). A diagnosis of adult-type ALCAPA was made.
CT coronary angiography. (A) CT axial imaging at the level of the right coronary artery (RCA) origin. (B) CT axial imaging of left main coronary artery (LMCA) orifice insertion into the left posterior lateral aspect of the main pulmonary artery (MPA). (C) Three-dimensional reconstruction showing dilated and tortuous RCA (black arrow), left coronary artery origin from the PA (red arrow) and dilated coronary collateral arteries along the surface of the heart.
ALCAPA is a rare congenital coronary anomaly associated with early infant mortality. About 10%–15% can survive to their adulthood due to compensatory development of intercoronary collaterals.1 2 These patients usually have dilated right coronary artery (RCA) and abundant collateral circulation supplying left coronary artery (LCA). Therefore, the pressure in the LCA consistently exceeds pulmonary artery in both systolic and diastolic period. Detection of dilated RCA and coronary collateral arteries by echocardiogram was highly suggestive of ALCAPA. Visualisation of the LCA origin from MPA by CT confirmed the diagnosis.3 4
Footnotes
Contributors SW prepared the first draft. HY and DP reviewed and edited the final manuscript. All authors are responsible for the overall content.
Funding This study was funded by National Natural Science Foundation of China (grant no: 81600359).
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.