Acute Mitral Regurgitation in Suspected Acute Coronary Syndrome: What Is the Cause?

Abstract

Patients presenting with acute chest pain and suspected acute coronary syndrome (ACS) who have nonobstructive coronary disease on angiography, but new regional wall motion abnormalities are often diagnosed with takotsubo cardiomyopathy (TTC). The cause of TTC is often physical or emotional stress, and this clinical syndrome occurs more often in women than men. When hemodynamically significant mitral regurgitation (MR) accompanies TTC, the mechanism must be carefully elucidated, as systolic anterior motion (SAM) of the mitral valve can cause significant MR and left ventricular outflow tract (LVOT) obstruction. These patients can be conservatively managed, with SAM-associated MR and LVOT obstruction resolving with medical therapy as TTC-associated left ventricular (LV) dysfunction resolves, as opposed to true ACS where further intervention for MR is often necessary. This case report describes 2 cases of TTC presenting with severe MR, who were initially thought to have ACS-associated MR caused by ischemia, but on further echocardiographic interrogation were found to have SAM-associated MR which resolved along with resolution of LV wall motion abnormalities on medical therapy by follow-up echocardiography.

Hypertrophic Cardiomyopathy with Intermittent Free Mitral Regurgitation–A Surgical Dilemma

“…2 SAM has been described as a transient or reversible finding in other conditions particularly with dynamic LV contraction, including acute myocardial infarction 3 or basal hyperkinesis with takotsubo cardiomyopathy. 4 However, the mechanism in this case is unusual with severe papillary muscle traction causing complete noncoaptation of the mitral valve. The resulting regurgitant flow pushes the thickened anterior chordae and leaflet toward the basal septum (movie clip S5), analogous to the previously described phenomenon of "atypical SAM."…”

Acute Mitral Regurgitation in Suspected Acute Coronary Syndrome: What is the Cause?

“…The refreshing report of Rao et al 1 about 2 patients with reversible mitral regurgitation (MR), left ventricular (LV) outflow tract pressure gradient (LVOTPG), and systolic anterior motion (SAM) of the mitral valve, attributed to Takotsubo syndrome (TTS), who were admitted with a picture of acute coronary syndrome, strikes a chord for this author, preoccupied for some time with the notion that transient MR and/or LV wallmotion abnormalities (WMAs) with subsequent amelioration, or complete resolution at repeat echocardiography (ECHO), observed particularly in postmenopausal women are formes frustes of TTS, and are common. 2 Although the 2 cases presented by the authors are very convincing, as to the underlying pathophysiology, one wonders whether milder cases of MR, without LVOTPG and SAM, and/or WMAs, represent cases of TTS.…”

Reply

“…We thank Dr. Madias for his erudite analysis of our study published in the journal, 1 and for putting it in context of what has been hypothesized and published on systolic anterior motion (SAM) of the mitral valve and left ventricular outflow tract (LVOT) obstruction in patients presenting with Takotsubo syndrome (TTS). We concur with the neuromechanical hypotheses forwarded by the author; "that in TTS the hypercontractility of the basal region and the akinesis/dyskinesis of the left ventricle (LV) apex are "part and parcel" of the pathophysiological neuromechanical derangement, mediated by the catecholamine induced stimulation of the b 1-, and b 2 -adrenergic receptors, and the latter's switch from cardiostimulatory to cardiodepressive functionality."…”