Classic Murmur, Unexpected Diagnosis: A Case Report and Pathophysiological Review

Figures

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  Figure 1. Resting 12‐lead electrocardiogram showing sinus rhythm at 69 bpm with a normal frontal plane axis and left‐sided chamber enlargement. Left atrial abnormality is suggested by a notched P wave in the limb leads. Left ventricular hypertrophy is suggested by frontal plane voltage criteria, including the aVL voltage criterion (RaVL ≥ 11 mm) and a positive Lewis index [(RI + SIII) − (RIII + SI) ≥ 17 mm].

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  Figure 2. (a) Transthoracic echocardiography, parasternal long‐axis M‐mode view, showing left ventricular dimensional and functional assessment. (b, c) Apical four‐chamber and apical two‐chamber views, respectively, demonstrating left ventricular volume assessment by modified Simpson′s method with endocardial border tracing for calculation of end‐diastolic and end‐systolic volumes. LV, left ventricle; LA, left atrium; RV, right ventricle; RA, right atrium.

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  Figure 3. (a) Bull′s eye plots showing peak systolic longitudinal strain (left) and time‐to‐peak longitudinal strain (right). Global longitudinal strain is preserved (−25%), with no significant regional heterogeneity in mechanical activation. (b) Speckle‐tracking echocardiography with segmental longitudinal strain analysis in apical four‐chamber (A4C), two‐chamber (A2C), and three‐chamber (A3C) views. Strain curves demonstrate preserved and synchronous myocardial deformation with a global longitudinal strain of −25%.

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  Figure 4. Transthoracic echocardiography, apical four‐chamber and apical two‐chamber views, showing left atrial volume quantification by modified Simpson’s method. Manual tracing of the left atrial endocardial borders revealed severe left atrial enlargement. LV, left ventricle; LA, left atrium.

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  Figure 5. (a) Parasternal long‐axis view demonstrating posterior mitral leaflet prolapse (P2 segment) with systolic displacement into the left atrium (arrow). Note the redundant leaflet tissue and the structurally normal aortic valve. (b) Apical four‐chamber view confirming posterior mitral leaflet prolapse with systolic billowing into the left atrium (arrow). Severe left atrial enlargement is evident, consistent with chronic volume overload. (c) Apical four‐chamber view demonstrating an interatrial septal aneurysm with systolic excursion toward the right atrium (arrow). LV, left ventricle; RV, right ventricle; LA, left atrium; RA, right atrium; ASA, atrial septal aneurysm; AO, ascending aorta.

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  Figure 6. (a) Parasternal long‐axis view with color Doppler imaging demonstrating vena contracta measurement of the mitral regurgitant jet at 0.56 cm. (b) Apical four‐chamber view with color Doppler imaging at reduced Nyquist limit, demonstrating the proximal flow convergence zone with a PISA radius of 0.72 cm, alongside continuous‐wave Doppler spectral tracing of the mitral regurgitant jet showing a dense, holosystolic envelope with a peak velocity of 497 cm/s and a velocity‐time integral of 165 cm. Derived quantitative parameters are reported in the text. (c) Apical three‐chamber views with color Doppler imaging demonstrating an eccentric mitral regurgitant jet directed anteromedially, hugging the left atrial wall adjacent to the aortic root consistent with the Coandă effect (white arrows). Laminar flow through the left ventricular outflow tract toward the ascending aorta is also visualized (yellow arrow). A wider color Doppler sector further demonstrates the wall‐hugging jet coursing along the interatrial septum toward the aortic root. LV, left ventricle; RV, right ventricle; LA, left atrium; AO, ascending aorta.

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  Figure 7. Schematic illustration depicting the pathophysiological mechanism of acoustic mimicry. In posterior mitral leaflet prolapse, the regurgitant jet assumes an anterior and medial trajectory, striking the aortic root and interatrial septum. Vibration of the left atrial wall adjacent to the aorta transmits acoustic energy to the left ventricular outflow tract and cervical structures, producing a murmur that mimics aortic stenosis.