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.

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.

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.

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.

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.

Echocardiographic examination of the posterior atrioventricular groove.

Abnormalities of the posterior atrioventricular (AV) groove may be mischaracterized or overlooked in the course of routine echocardiographic imaging. Vascular abnormalities in this location include plethora of the coronary sinus and ectasia of the circumflex coronary artery. Excess accumulation of calcium (mitral annular calcification) and of fat (lipomatosis of the posterior AV groove) may also occur in this region. Masses (tumors or thrombus) arising from the floor of the left atrium or extrinsic to it (hiatal hernia, lymph nodes) may occupy the posterior AV groove. Abnormalities of the left ventricle, including aneurysms and pseudoaneurysms may present as masses in the posterior AV groove. This article discusses the echocardiographic features, differential diagnosis, and clinical significance of these abnormalities.

Does left atrial enlargement contribute to mitral leaflet tethering in patients with functional mitral regurgitation? Proposed role of atriogenic leaflet tethering.

Papillary muscle repositioning due to left ventricular remodeling is thought to be the primary mechanism responsible for functional mitral regurgitation. This article proposes that remodeling (enlargement) of the left atrium also plays a role in the pathogenesis of functional mitral regurgitation, through a novel mechanism-atriogenic leaflet tethering-described herein.

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.

Pseudoaneurysm formation in infective endocarditis.

Left ventricular pseudoaneurysms that develop in the setting of infective endocarditis are believed to result from remodeling of extravalvular abscesses. The high pressure generated by the left ventricle is thought to dissect into the abscess causing it to form a characteristic sac-like protuberance readily recognized echocardiographically. Left ventricular pseudoaneurysms most often arise from abscesses in the mitral-aortic intervalvular fibrosa and protrude external to the aorta. Less often, as described herein, they arise from abscesses external the posterior mitral annulus and project into the posterior interventricular groove. Perforation may result in camo-cameral or aorto-cameral fistula formation, as well as fistulous communication with the pericardial space.

Coronary artery disease in South Asian immigrants living in New York City: angiographic findings and risk factor burdens.

BACKGROUND: The prevalence of coronary artery disease (CAD) among South Asians (SAs) significantly exceeds that of Caucasians. South Asians also suffer from more premature, clinically aggressive and angiographically extensive (3-vessel) disease. The role of conventional CAD risk factors (CCRFs) remains controversial. OBJECTIVES: We sought to determine if the CCRF burdens of SA immigrants differed from Caucasians. We also sought to determine whether angiographic CAD was more extensive among SAs and whether SA ethnicity was an independent predictor of 3-vessel disease. METHODS: We reviewed the CCRFs and angiograms of 520 SAs and 219 Caucasians consecutively referred with stable angina pectoris or acute coronary syndrome. RESULTS: Three-vessel CAD was significantly more common among SAs than Caucasians (32.5% vs 22.4%; P = .006). Diabetes mellitus (DM), age and male sex independently predicted 3-vessel disease. South Asian ethnicity showed a trend toward predicting 3-vessel disease (P = .06). The frequency of DM (55% vs 31.1%; P < .001), hypertension (77.5% vs 68.5%; P = .01), obesity (63.1% vs 44.3%; P < .001) and dyslipidemia (75.6% vs 61.6%; P < .001) were significantly greater among SAs; however, smoking was significantly more common among Caucasians (44.3% vs 21.3%; P < .001). Compared to Caucasians, SAs were significantly younger at the time of presentation for coronary angiography (58.5 vs 61.1 yrs; P = .001). CONCLUSIONS: SAs referred for coronary angiography with stable angina and acute coronary syndromes are younger, have significantly higher rates of 3-vessel disease, as well as higher rates of DM, hypertension, obesity and dyslipidemia than Caucasians. Aggressive screening, prevention and treatment may be warranted in this population.

Anatomy, mechanics, and pathophysiology of the mitral annulus.

The mitral annulus plays an important role in leaflet coaptation, in unloading mitral valve closing forces, and in promoting left atrial and left ventricular filling and emptying. Perturbations of annular mechanics figure prominently in a number of disorders including functional and ischemic mitral regurgitation, mitral valve prolapse, atrial fibrillation, mitral annular calcification, and annular submitral aneurysm. This review discusses the role of annular dysfunction in the pathogenesis of these disorders.

Coronary angiographic findings and conventional coronary artery disease risk factors of Indo-Guyanese immigrants with stable angina pectoris and acute coronary syndromes.

BACKGROUND: The prevalence of coronary artery disease (CAD) among migrant Indian populations exceeds that of Caucasians. Migrant Indians also suffer from more premature, clinically aggressive and angiographically extensive, (i.e., 3-vessel disease). It is not known whether the extent of angiographic CAD or the conventional CAD risk factors of Indo-Guyanese (IG) immigrants differs from that of Caucasians. METHODS: We reviewed the conventional CAD risk factors and angiographic findings of 198 IG and 191 Caucasians who were consecutively referred for cardiac catheterization with a diagnosis of stable angina pectoris or acute coronary syndrome. RESULTS: Three-vessel CAD was approximately 1.5 times more common among IG than Caucasians (34.8% vs. 24.0%; P = .02). Age (P = .01), male sex (P = .03) and diabetes mellitus (P = .05) were independently associated with an increased likelihood of 3-vessel CAD and there was a trend towards IG ethnicity predicting 3-vessel disease (P = .13). The frequency of diabetes mellitus (51.5% vs. 30.9%; P <.001), hypertension (82.3% vs. 67.0%; P < .001) and dyslipidemia (75.5% vs. 60.2%; P = .001) were significantly greater among IG, however, that of smoking was not. While IG were significantly leaner than Caucasians (27.7 kg/m2 vs. 30.0 kg/m2 ; P < .001), their mean body mass index fell within the ethnic-specific range for obesity. CONCLUSIONS: We conclude that IG immigrants presenting for coronary angiography have significantly higher rates of 3-vessel CAD as well as higher rates of diabetes mellitus, hypertension and dyslipidemia than Caucasians. Aggressive screening, prevention and treatment may be warranted in this cohort.

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.

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.

The role of shear stress in the pathogenesis of discrete subaortic stenosis: implications for surgical treatment.

Discrete subaortic stenosis (DSS) is characterized by the presence of an obstructing membrane in the left ventricular outflow tract (LVOT). Evidence suggests that the formation of DSS represents a fibroproliferative reaction of the endocardium occurring in response to alterations in shear stress caused by geometric abnormalities within the LVOT. The aim of this review is to discuss the role of altered LVOT shear stress in the pathogenesis of DSS, and its implications in surgical decision making.

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.