Non-ischemic rupture of the posteromedial papillary muscle due to Streptococcus agalactiae endocarditis.

Papillary muscle rupture is usually caused by myocardial infarction although rare cases of non-ischemic etiology have also been described. Among these, infective endocarditis represents an important cause. Herein, we report a case due to Streptococcus agalactiae involving the posteromedial papillary muscle. Learning objective: Non-ischemic papillary muscle rupture should be suspected when there is no evidence of atherosclerotic coronary artery disease. In the febrile patient, infective endocarditis should be considered in the differential diagnosis.

Do False Tendons Prevent Adverse Left Ventricular Remodeling After Anterior Wall Myocardial Infarction? An Echocardiographic Strain Imaging Study.

The role of muscular left ventricular (LV) false tendons (FTs) is poorly understood. To gain insight into their pathophysiologic significance, we adapted echocardiographic LV strain imaging software to measure LVFT longitudinal strain in subjects with normal left ventricles and in patients who sustained previous anterior wall myocardial infarction (AWMI). GE EchoPAC software was used to measure longitudinal strain in LVFTs ≥0.3 cm in diameter. Tendinous strain was measured in 11 patients with LVFTs confined to the left anterior descending artery territory (connecting the anteroseptum or anterior wall to the apex) ≥6 months after AWMI (myocardial infarction [MI]+FT+ group) and in 25 patients with normal hearts containing LVFTs (MI-FT+ group). We also compared the indexed LV end-diastolic volumes in the MI+FT+ group to that of 25 patients with previous AWMI without LVFTs (MI+FT- group). The mean LVFT strain in MI+FT+ group was 5.5 ± 6.2% and -28.9 ± 4.7% in the MI-FT+ group (p <0.0001). The indexed LV end-diastolic volume in the MI+FT+ group did not differ from the MI+FT- group (88.4 ± 17.8 vs 87.9 ± 17 ml/m2, p = 0.90). In conclusion, the negative strain (contraction) developed by LVFTs in the MI-FT+ group may help maintain normal LV size and shape by generating inward restraining forces. The development of positive strain (stretch) in LVFTs in patients in the MI+FT+ group suggests they become infarcted after AWMI. This implies that they are incapable of generating inward restraining forces that might otherwise mitigate adverse remodeling. Of note, LV volumes after AWMI do not differ whether or not LVFTs are present.

Pathophysiology, Echocardiographic Diagnosis, and Treatment of Atrial Functional Mitral Regurgitation: JACC State-of-the-Art Review.

The conventional view holds that functional mitral regurgitation (MR) is caused by restriction of leaflet motion resulting from displacement of the papillary muscle-bearing segments of the left ventricle. In the past decade, evidence has accrued suggesting functional MR can also be caused by left atrial enlargement. This underrecognized cause of secondary MR-atrial functional MR (AF-MR)-is mechanistically linked to annular enlargement, perturbations of annular contraction, and atriogenic leaflet tethering. AF-MR has been described in patients with atrial fibrillation and heart failure with preserved ejection fraction. Preliminary data suggest rhythm control may decrease MR severity in patients with atrial fibrillation. Additionally, several studies have reported reductions in MR and symptomatic improvement with restrictive annuloplasty and transcatheter edge-to-edge repair. This review discusses the pathophysiology, echocardiographic diagnosis, and treatment of AF-MR. AF-tricuspid regurgitation is also discussed.

Cardiac Imaging for Diagnosis and Management of Infective Endocarditis.

Imaging is central to the care of patients with infective endocarditis. Although transthoracic and transesophageal echocardiography are the principal imaging techniques, additional modalities including positron emission tomography and cardiac computed tomography, and to a lesser extent intracardiac echocardiography, play an increasing role. This review discusses the role of cardiac imaging in establishing the diagnosis of endocarditis, in predicting its embolic risk, and in making decisions regarding the need for and timing of surgery.

Pseudoaneurysm of the mitral-aortic intervalvular fibrosa with fistulous communication to the left atrium causing congestive heart failure.

Pseudoaneurysms of the mitral-aortic intervalvular fibrosa can rupture and form fistulous communications between the left ventricle and left atrium. Pulmonary venous systolic flow reversal in such cases reflects elevated left atrial pressure due to shunting. This finding, particularly in the setting of endocarditis, is not specific for severe mitral regurgitation.

Mitral Annular Calcification and Calcific Mitral Stenosis: Role of Echocardiography in Hemodynamic Assessment and Management.

As the life expectancy of the population continues to increase, mitral annular calcification has emerged as an important cause of mitral stenosis (MS), commonly referred to as calcific or degenerative MS. Mitral annular calcification results in valvular stenosis when calcification extends into the base of the mitral leaflet(s) and displaces the mitral valve hinge point(s) into the left ventricular inlet. Echocardiographic determination of mitral vale area is fraught with difficulties and often precludes using planimetry or the Hatle formula. Given the numerous confounders that affect transmitral flow in calcific MS, evaluation of lesion severity should incorporate flow-independent methods such as the continuity equation and the mitral valve dimensionless index. In light of the significant risks entailed, there is little enthusiasm for mitral valve replacement in patients with calcific MS. Transcatheter mitral valve replacement is generally offered on a compassionate use basis to patients deemed to be at high surgical risk.

Advances in Rheumatic Mitral Stenosis: Echocardiographic, Pathophysiologic, and Hemodynamic Considerations.

Echocardiography is the primary imaging modality used in patients with mitral stenosis. Doppler-derived measurements of mitral pressure half-time are commonly used to calculate mitral valve area, but a number of hemodynamic confounders associated with advanced age limit its utility. Planimetry remains the gold standard for determining mitral valve area and may be performed using two- or three-dimensional imaging. Although the Wilkins score has been used for >30 years to predict balloon mitral valvuloplasty outcomes, newer scoring systems have been proposed to improve predictive accuracy. Some patients undergoing technically successful balloon mitral valvuloplasty may not have satisfactory clinical outcomes. These individuals may be identified by the presence of reduced net atrioventricular compliance, which can be measured echocardiographically. Exercise testing may be useful in patients with mitral stenosis whose symptomatic status is incongruous their mitral valve area. Last, reduced left atrial systolic strain, an indicator of poor left atrial compliance, has been shown to reliably predict adverse outcomes in patients with mitral stenosis. The author discusses the hemodynamics and path ophysiology of mitral stenosis and reviews current and emerging roles of echocardiography in its evaluation.

Characterization of Myocardial Injury in Patients With COVID-19.

BACKGROUND: Myocardial injury is frequent among patients hospitalized with coronavirus disease-2019 (COVID-19) and is associated with a poor prognosis. However, the mechanisms of myocardial injury remain unclear and prior studies have not reported cardiovascular imaging data. OBJECTIVES: This study sought to characterize the echocardiographic abnormalities associated with myocardial injury and their prognostic impact in patients with COVID-19. METHODS: We conducted an international, multicenter cohort study including 7 hospitals in New York City and Milan of hospitalized patients with laboratory-confirmed COVID-19 who had undergone transthoracic echocardiographic (TTE) and electrocardiographic evaluation during their index hospitalization. Myocardial injury was defined as any elevation in cardiac troponin at the time of clinical presentation or during the hospitalization. RESULTS: A total of 305 patients were included. Mean age was 63 years and 205 patients (67.2%) were male. Overall, myocardial injury was observed in 190 patients (62.3%). Compared with patients without myocardial injury, those with myocardial injury had more electrocardiographic abnormalities, higher inflammatory biomarkers and an increased prevalence of major echocardiographic abnormalities that included left ventricular wall motion abnormalities, global left ventricular dysfunction, left ventricular diastolic dysfunction grade II or III, right ventricular dysfunction and pericardial effusions. Rates of in-hospital mortality were 5.2%, 18.6%, and 31.7% in patients without myocardial injury, with myocardial injury without TTE abnormalities, and with myocardial injury and TTE abnormalities. Following multivariable adjustment, myocardial injury with TTE abnormalities was associated with higher risk of death but not myocardial injury without TTE abnormalities. CONCLUSIONS: Among patients with COVID-19 who underwent TTE, cardiac structural abnormalities were present in nearly two-thirds of patients with myocardial injury. Myocardial injury was associated with increased in-hospital mortality particularly if echocardiographic abnormalities were present.

The anatomic substrate of mitral annular contraction.

BACKGROUND: Despite the absence of contractile elements, the mitral annulus undergoes sphincter-like "contraction" resulting in an area reduction of approximately 25%. Its anatomic basis has not, however, been delineated. Since annular contraction helps draw the mitral leaflets into apposition, an appreciation of its anatomic basis could enhance our understanding of the pathogenesis of mitral regurgitation. METHODS: Gross dissection of >100 bovine, ovine and human hearts as well as histologic examination of 5 ovine hearts was performed to ascertain the origins, course and insertion points of the atrial and ventricular muscle bundles related to the annulus. RESULTS: Significant circumferentially-oriented left atrial fibers derived from Bachman's bundle flank the annulus internally. These fibers encircle the base of the atrium and insert into the right fibrous trigone. Externally, the annulus is anatomically related to the superficial obliquely-oriented fibers of the left ventricular inlet which course from the subepicardium to the subendocardium. CONCLUSIONS: Intercalation of the annulus between the musculature of the left atrium and left ventricle subjects it to extrinsic contractile forces resulting in sphincter-like narrowing. The circumferential fibers of the left atrial base are favorably positioned such that their contraction imparts a centripetal force onto the inner aspect of the adjacent fibrous annulus which causes it to translate inward in late diastole. During systole, the superficial oblique fibers of the left ventricular inlet, impose a torsional force onto the outer aspect of the annulus causing it to translate inwards. These observations may have mechanistic implications in mitral regurgitation.

Mechanisms, pathophysiology, and diagnostic imaging of left ventricular outflow tract obstruction following mitral valve surgery and transcatheter mitral valve replacement.

Left ventricular outflow tract obstruction is a serious complication of mitral valve surgery (repair and replacement) and transcatheter mitral valve replacement. An appreciation of the various mechanisms which cause outflow obstruction in these settings is critical to avoiding this complication and to initiating appropriate treatment. This article discusses the mechanisms, pathophysiology, and imaging of left ventricular outflow tract obstruction which can arise following insertion of a variety of mitral valve prosthetics.

Atrial functional tricuspid regurgitation: An underappreciated cause of secondary tricuspid regurgitation.

Secondary tricuspid regurgitation (TR) caused by right ventricular enlargement in the setting of left heart disease/pulmonary hypertension has been well described. In contrast, that associated with right atrial enlargement-atrial functional TR (AF-TR)-remains largely underappreciated. AF-TR most often occurs in the setting of lone atrial fibrillation, although it is also seen in its absence (idiopathic AF-TR). Several recent studies have found that the prevalence, hemodynamic significance, and prognosis of AF-TR are not inconsequential, suggesting increased physician awareness of this novel clinical entity is warranted. This article discusses the pathogenesis, echocardiographic findings, and treatment of this underappreciated cause of secondary TR.

Pathophysiology and Echocardiographic Diagnosis of Left Ventricular Diastolic Dysfunction.

Echocardiography is the primary imaging modality used for the clinical evaluation of left ventricular (LV) diastolic function. Using two-dimensional together with transmitral, mitral annular, and pulmonary venous Doppler data, conclusions may be drawn regarding the relaxation and compliance properties of the ventricle that can be used for estimating LV filling pressure. Echocardiographic estimation of LV filling pressure has been shown to be especially useful for evaluating patients with dyspnea of unknown etiology as well as those with heart failure with preserved ejection fraction. Moreover, echocardiographic estimation of LV filling pressure can be used for clinical decision making on day-to-day basis. This article discusses the pathophysiology of diastolic dysfunction and provides a comprehensive review of its echocardiographic evaluation.

Malaligned bioprosthetic valve causing left ventricular outflow tract obstruction.

Left ventricular outflow tract obstruction resulting from strut impingement upon the interventricular septum is a rare complication of bioprosthetic mitral valve insertion. Obstruction is more likely to develop when a small, high profile prosthetic valve is inserted into a patient with a small outflow tract. The likelihood of this complication may be reduced by appropriate modification of surgical technique.

Mechanistic insights into atrial functional mitral regurgitation: Far more complicated than just left atrial remodeling.

Recent studies lend credibility to the notion that lone atrial fibrillation (AF) can cause functional mitral regurgitation (MR), commonly referred to as atrial functional MR (AF-MR). The conventional view holds that left atrial enlargement associated with AF causes annular dilatation which gradually moves the mitral valve leaflets apart resulting in inadequate coaptation and regurgitation. Recent findings, however, suggest that AF-MR is not solely related to left atrial remodeling, but that important structural and functional abnormalities of the left ventricle also play a role in its pathogenesis.

The transverse and oblique sinuses of the pericardium: Anatomic and echocardiographic insights.

A number of masses and pseudomasses may be encountered during the echocardiographic examination of the transverse and oblique sinuses with significant clinical implications. This review discusses the clinically relevant anatomy of the pericardial sinuses emphasizing diagnostic pitfalls that may be encountered during their echocardiographic examination.

Papillary muscle rupture following acute myocardial infarction: Anatomic, echocardiographic, and surgical insights.

Papillary muscle (PM) rupture is a rare complication of acute myocardial infarction which carries an excessive mortality rate. Optimal outcomes require rapid diagnosis and prompt surgical referral, and in this regard, echocardiography plays a crucial role. Comprehensive echocardiographic examination of the patient with PM rupture consists of identification of the ruptured PM segment, visualization of flail mitral valve segment(s), evaluation of mitral regurgitation severity, and assessment of left ventricular systolic function. This article discusses anatomic and echocardiographic features as well as the surgical management of PM rupture.

Pectus excavatum: echocardiographic, pathophysiologic, and surgical insights.

Patients with pectus excavatum (PEX) may be referred for echocardiographic examination for a variety of complaints including exercise intolerance, dyspnea, palpitations, or chest pain. It is therefore important for the echocardiographer to have an appreciation of the various abnormalities associated with this disorder. Echocardiographic imaging may reveal a number of structural alterations of the right ventricle as well as a reduction in right ventricular systolic function. Interestingly, a number of these abnormalities have also been described in patients with arrhythmogenic right ventricular dysplasia, although patients with PEX do not share a predilection for malignant ventricular arrhythmias. Additional echocardiographic abnormalities associated with PEX include prolapse of the mitral and/or tricuspid valves, Marfan's aortopathy, pericardial effusion, prominence of the crista terminalis, and possibly a number of congenital cardiac anomalies. This review discusses the echocardiographic abnormalities associated with PEX and their pathophysiologic significance. The effects of corrective orthopedic surgery on cardiac function are also discussed.