Hypertrophic cardiomyopathy and tako tsubo syndrome with left ventricular outflow tract obstruction: a thin line

Abstract A 75-years-old Caucasian man presented to the Emergency Department due to worsening dyspnoea and leg oedema in the previous days. His past medical history was significant for a minor surgical operation performed a few days earlier. A previous echocardiography described a hypertrophic left ventricular septum (IVSd 14 mm) in the absence of significant hypertension, with an intraventricular pressure gradient of 10 mmHg at rest and a prolapse of the anterior mitral leaflet. At the time of the admission, tachycardia and a 2/6 cardiac murmur were observed and blood tests showed elevated high-sensitivity Troponin T and N-terminal-pro-B-type natriuretic peptide. The EKG showed synus rhythm and sign of ventricular hypertrophy. Therefore ,the patient was transferred to the Cardiology department and therapy for a subacute coronary syndrome was initiated. A transthoracic echocardiogram revealed a hypertrophic left ventricle (IVSd 15 mm), with apical ballooning shape resulting in a moderately reduced ejection fraction. Moderate mitral regurgitation with systolic anterior movement of the anterior mitral leaflet (SAM), was observed, and an estimated left intraventricular gradient of 108 mmHg at rest was recorded. The patient underwent a coronary angiography: no critical obstructive coronary disease was observed. During ventriculography a typical apical ballooning was revealed and a Tako-Tsubo Syndrome was confirmed, besides this an intraventricular gradient of 34 mmHg was measured. A beta-blocker therapy was promptly initiated (metoprolol), since the patient was haemodynamically stable and QTc was only mildly prolonged. A cardiac magnetic resonance (CMR) performed at day 20, excluded both ischaemic pattern and signs of previous myocarditis. Furthermore, CMR showed an only mildly hypertrophic left ventricle (IVSd 12 mm) and no fibrosis, further supporting the idea that in our patient LVOTO was part of TTS physiopathology and not the sign of an underlying hypertrophic cardiomyopathy. One month later echocardiography showed a completely restored left ventricular systolic function; LVOTO was no more detectable and a complete normalization of left ventricular thickness was observed, in accordance with many papers describing a reversible hypertrophy induced by TTS. Early LVOTO, the one experienced by our patient, is a quite common complication of TTS. It is more often observed among the elderlies, in patient with redundant mitral valve leaflets and in those with septal hypertrophy. Besides this, late onset LVOTO is also described: it is only partially reversible and requiring a previous underlying cardiopathy. In both cases, LVOTO is an established bad prognostic factor. The existing evidence discourages the administration of inotropic agents and nitrates, supporting instead the use of beta-blockers aiming at reducing intraventricular gradient. In patients with haemodynamic instability and significant LVOTO, short acting beta blockers should be preferred, although concomitant hypotension may impose the use of mechanical support therapy. On the contrary, clinically stable patients often benefit from oral administration of beta blockers. In conclusion, LVOTO is a common complication of TTS that must be discerned from a probable underlying hypertrophic cardiomyopathy, that can be excluded only after observing a complete reversibility.