The mitral annulus (MA) is not a continuous ring of connective tissue from which are suspended mitral leaflets. Instead, it is a much more complex structure made up of a mix of fibrous, muscular, and adipose tissues. MA is a key structure in any type of mitral valve repair and recently it has been targeted for transcutaneous devices. Thus, a deep understanding of MA anatomy has never been more important. Traditionally, cardiac anatomy has been described using anatomic specimens. Currently, sophisticated non-invasive techniques allow imaging of MA with a richness of anatomical details unimaginable only two decades ago. The aim of this review is to provide a better understanding of the peculiar aspects of MA as they are revealed through these imaging techniques and discuss clinical implications related to this complex structure.

Objectives Degenerative mitral regurgitation (DMR) is classified into different phenotypes based on the extent of leaflet degeneration. Our aim is to demonstrate that phenotype complexity predicts the extent of structural abnormalities of mitral annulus (MA). Methods and results Seventy‐five patients with DMR and severe valve regurgitation and 23 patients with normal mitral valve were studied using 3D transesophageal echocardiography. Classification of DMR was done by allocating each 3D echocardiography result under five categories: fibroelastic deficiency (FED), FED+, forme fruste, Barlow’s disease Mitral annular disjunction (BD MAD)– or BD MAD+. MA was reconstructed in early systole and in end systole. We tested for a trend toward enlargement and flattening of MA in end systole and for a difference in MA dynamics from early systole to end systole with a worsening of DMR phenotype, in the whole spectrum of subjects ranging from controls to BD MAD+. A significant trend was observed toward larger anteroposterior diameter, intercommissural diameter, annulus circumference, and annulus area (P < .001). A reduction was found in annulus height to commissural width ratio (P = .003): This indicates a progressive MA flattening. Prolapse height and prolapse volume tended to be larger (P < .001). Conclusion Based on the extent of leaflet degeneration, DMR is classified into different phenotypes. As the disease progresses, a related increase in MA size is found, with rounder annular shape, loss of saddle shape, and increase in height and volume of leaflet prolapse. The most pronounced alterations are found in BD MAD+.

Funding Acknowledgements None Background Acute myocarditis is a clinical and pathological condition defined as an inflammation of the myocardium. Its diagnosis is often challenging and requires multiple information derived from different diagnostic modalities. Purpose The aim of the study is to evaluate the correlation between electrocardiographic and imaging data in patients with acute myocarditis. Methods We made a retrospective analysis of 102 patients admitted to our Centre between January 2012 and April 2019 for suspected acute myocarditis. Diagnosis was confirmed with cardiac magnetic resonance (CMR) by identification of myocardial edema in T2-weighted images and/or typical subepicardial or midwall pattern of late gadolinium enhancement (LGE). Significant coronary artery disease was ruled out with coronary angiography. Electrocardiogram (ECG) was analysed on admission - in order to evaluate the presence of ST segment abnormalities, atrio-ventricular or bundle-branch block and heart rhythm disorders - and at the time of discharge. Every patient underwent echocardiography and CMR: from both these exams we reported the presence of regional wall motion abnormalities and left ventricular ejection fraction (LVEF). Results Mean age of our population was 39 ± 18 years; 92 people (90%) were males. At admission, 85 patients (83%) presented ECG abnormalities; the most frequent was ST-segment elevation (65 cases). Conduction or rhythm disorders were observed in 26 cases (25%). At the time of discharge, 41 out of 85 patients had complete regression of ECG changes. Mean value of LVEF measured with echocardiography was 56.4 ± 7.6%. In patients with normal ECG on admission it was 59.9 ± 3.1%, whereas in patients with abnormal ECG 55.7 ± 7.9% (p = 0.045). Considering CMR, mean LVEF in the population was 58.5 ± 8.6%, varying between 64.0 ± 8.9% in the group with normal ECG and 57.4 ± 10.1% in the group with ECG abnormalities (p = 0.02). Moreover, subjects with altered ECG on admission had a higher prevalence of wall motion abnormalities both in echocardiography (47/85 – 55% vs 3/17 – 18%, p &lt; 0.01) and in CMR (45/85 – 53% vs 3/17 – 18%, p &lt; 0.01). Patients with ECG normalization at discharge had a higher prevalence of ST-segment elevation (88 vs 66%, p = 0.02), while the group with persistent ECG alterations had a higher incidence of AV or bundle-branch block (23 vs 7%, p = 0.048). No statistical difference was noted between these two groups regarding echocardiographic or CMR values. Conclusion In our experience evaluation of ECG at admission in patients with suspected acute myocarditis identifies a subgroup of individuals with lower values of LVEF and a higher prevalence of wall motion abnormalities both in echocardiography and in CMR, while data derived by imaging techniques had no significant predictive value on ECG evolution at the time of discharge.

Cardiovascular magnetic resonance (CMR) is the gold standard technique to comprehensively assess cardiac structure and function. A 64-year-old male, planned for surgical coronary revascularization, underwent transthoracic and transesophageal echocardiography for a mitral regurgitation, with an eccentric jet of unclear mechanism; these examinations were inconclusive because of the lack of adequate visualization of the cardiac structures. A CMR was then performed to quantify mitral regurgitation and, additionally, it documented a giant hiatus hernia with gastric sliding into the thorax. In this case, CMR helped to better define the severity of a valvular disease and provided ancillary information from the extracardiac findings.

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