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Abstract
Clinical introduction A 21-year-old, previously healthy, woman presents to the emergency department with 2 months of dyspnoea on exertion. She is short of breath walking up a flight of stairs. She has a history of intravenous drug use and takes no medications. Family history is negative for cardiac disease. Heart rate is 110 bpm and blood pressure is 125/55 mmHg. She has an elevated jugular venous pressure, bibasilar rales, a soft S1 and a systolic in addition to a diastolic murmur. Shortly after initial presentation in the emergency department, she is intubated for respiratory failure. A transthoracic echocardiogram is obtained (figure 1).
(A) M-mode recording of the mitral valve. (B) Continuous-wave Doppler of transmitral flow.
Question In addition to abstinence from drug use, which of the following is the most appropriate definitive therapy?
Mitral valve repair
Aortic valve replacement
Balloon mitral commissurotomy
Dual-chamber pacemaker
Septal myectomy
Question
- Echocardiography
- Valve disease surgery
- Valvular heart disease
- Endocarditis
- Aortic regurgitation
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ANSWER: B
Figure 1 shows early mitral valve closure and diastolic mitral regurgitation (MR) due to elevated left ventricular (LV) diastolic pressure which, in this case, results from acute aortic regurgitation (AR). While other aetiologies of mitral stenosis or regurgitation (including diastolic MR) exist, none of these lead to all the findings shown in figure 1.
In acute AR, the volume load into a non-compliant LV causes LV pressure to surpass left atrial (LA) pressure during mid-diastole, causing premature mitral valve closure,1 2 shown by M-mode. Further increase in the LV-LA pressure gradient during late diastole leads to diastolic MR,3 as shown by the spectral Doppler.
This patient has aortic valve endocarditis causing acute severe AR, shown by diastolic flow reversal in the descending aorta and rapid pressure half-time of the AR jet (figure 2, see online Supplementary videos), corresponding to the early diastolic murmur. Increased flow across the aortic valve causes a systolic murmur. She was given antibiotics and underwent emergent aortic valve replacement.
(A) Parasternal long-axis view showing aortic valve vegetation. (B) Diastolic flow reversal in the descending thoracic aorta. (C) Continuous-wave Doppler of transaortic flow. (D) Holodiastolic flow reversal in the abdominal aorta.
Atrioventricular block can cause diastolic MR but not early mitral valve closure or increased transmitral gradients.3 The PR interval is normal so pacemaker placement is not indicated.
Rheumatic mitral stenosis causes the leaflets to look thick and echogenic by M-mode and a flat closure slope after the E-point separation, none of which is shown here. Therefore, rheumatic mitral stenosis is unlikely and balloon mitral commissurotomy is inappropriate. The high mitral diastolic gradient in figure 1 is due to increased mitral inflow and high LA pressure, not mitral stenosis.
Figure 1 does not show posterior systolic bowing of the leaflets characteristic of mitral valve prolapse, which does not cause diastolic MR. Therefore, mitral valve repair is not indicated.
Septal wall thickness is normal by M-mode, making hypertrophic cardiomyopathy unlikely. Systolic anterior motion of the mitral valve is also absent so septal myectomy is not appropriate.
Footnotes
Contributors All authors participated in the writing and editing of the manuscript, as well as data collection.
Competing interests None declared.
Ethics approval Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.