Antonio J. Chamoun

Mitral regurgitation following acute myocardial infarction

Mitral valve regurgitation (MR) is a frequent Doppler echocardiographic finding in patients after acute myocardial infarction (AMI) and an independent predictor of long-term cardiovascular mortality. Reported risk factors include advanced age, prior myocardial infarction, infarct extension, and recurrent ischemia. During the early phase of AMI, transient ischemic MR is common and rarely causes hemodynamic compromise. However, when several chordae tendineae or a papillary muscle ruptures, acute left atrial and ventricular volume overload ensues, leading to abrupt hemodynamic deterioration with cardiogenic shock. Auscultation may be unrevealing due to decreased turbulence. Hence, the importance of a high index of suspicion for acute MR in any patient with acute pulmonary edema in the setting of AMI, especially if left ventricular systolic function is well preserved. Later, ventricular remodeling may lead to MR through annular dilatation or papillary muscle migration with malcoaptation of the leaflets. The widespread availability, ease of use and non-invasive nature of Doppler echocardiography have made it the standard diagnostic tool for detecting MR. Mechanical reperfusion of the infarct-related artery seems to be superior to fibrinolysis in decreasing its incidence acutely and in the long run. Nevertheless, when acute severe MR occurs, unless rapidly diagnosed and treated, this dreaded complication is associated with high morbidity and mortality. Prompt surgical intervention after hemodynamic stabilization is essential to ensure a good short-term and long-term prognosis. This review discusses the incidence, long-term prognosis, associated risk factors, complex pathophysiology, time of occurrence, clinical manifestations, diagnosis, and management of patients with MR after AMI.

Ventricular free wall rupture following acute myocardial infarction

SUMMARY Ventricular free wall rupture remains a dreaded complication of acute myocardial infarction. A dramatic fatal presentation is not universal and if recognized early, especially in its sub-acute form, a therapeutic intervention may be lifesaving. Changing trends in its natural history and the previously described pathological subtypes have emerged since the advent of thrombolysis. Although frequently unpredictable, certain clinical, echocardiographic and electrocardiographic signs should suggest the diagnosis. Moreover, knowledge of predisposing risk factors and a high index of suspicion are helpful in early recognition of this complication. In recent years, several different therapeutic approaches have been described including percutaneous seals and surgical mechanical closure of ventricular free wall rupture. In this review, we sought to highlight established and debatable aspects of this pathology to hopefully enhance prompt diagnosis and treatment by all clinicians caring for patients suffering acute myocardial infarction.

Color M-mode flow propagation velocity versus conventional Doppler indices in the assessment of diastolic left ventricular function in patients on chronic hemodialysis.

Background and Objective: Color M‐mode flow propagation velocity (Vp) has been reported as a preload‐independent measure of diastolic function. To study the effects of loading conditions on diastolic function assessment in patients on chronic hemodialysis, we measured Vp and conventional Doppler indices pre‐ and posthemodialysis. Methods: Twenty hemodialysis patients with normal systolic function underwent measurement of Vp, early filling velocity (E), its deceleration time (DT), atrial contraction velocity (A), isovolumic relaxation time (IVRT), and pulmonary atrial flow reversal velocity (PFR) pre‐ and posthemodialysis. Twelve healthy controls underwent these same measurements. Results: Hemodialysis patients had significantly slower Vp at baseline than normal controls, while E/A, DT, IVRT, and pulmonary flow reversal were not significantly different. E, IVRT, and PFR were affected by hemodialysis, while color M‐mode flow propagation velocities, A, and DT were not. Conclusions: Color M‐mode flow propagation velocity seems to be a preload‐independent measure of diastolic function in chronic hemodialysis patients in whom isolated diastolic dysfunction appears prevalent.

MTHFR 677 C-->T mutation: a predictor of early-onset coronary artery disease risk.

The atherosclerotic potential of the methyenetetrahydrofolate reductase (MTHFR) gene mutation 677 C --> T substitution remains controversial. In this study, we describe the association of this mutation in a Southern Texan patient population of multiracial ethnic background with risk and extent of coronary artery disease (CAD) as measured by luminal narrowing. Sixty nine patients who were 50 years or younger composed our population. Chi-square analysis was used to analyze the data and found a significant association between CAD and this mutation (P value=0.03). In addition, in the small number of patients in this study who had diabetes, those who had mutation have more severe disease than those without the mutation. This study highlights the potential cardiovascular prognostic significance of the MTHFR 677 C --> T in the studied population.

Real-Time Three-Dimensional Echocardiography With Real-Time Volume Rendering in Assessment of Left Ventricular Apical Thrombi

A 36-year-old man with dilated cardiomyopathy was admitted for worsening congestive heart failure. A 2D echocardiogram showed enlargement of the left chambers with global left ventricular hypokinesis; ejection fraction was estimated at 35%. Mild regurgitations of the mitral and tricuspid valves were noted, and the pulmonary artery pressure was estimated at 43 to 48 mm Hg. An echo-dense mass, most consistent with a thrombus, was seen at the apex of the left ventricle. Visualization was partial in the apical views and full in the subcostal view. The …

Mitral Valve Prolapse: A Review of the Literature

M valve prolapse (MVP) is a common valvular disorder characterized by abnormalities of the mitral valve apparatus that result in “billowing” of 1 or both mitral leaflets into the left atrium during systole, with or without mitral regurgitation (MR).1–3 It is the most frequently diagnosed valve abnormality in the industrial world,4,5 and the most common primary cause for dysfunction requiring mitral valve repair or replacement.6 Clinical classification may have significant overlap and “the pathogenesis of symptoms is not completely understood.”7 The overall incidence (by echocardiography) in the Framingham study was 5%, with a frequency in women approximately twice that of men.8 Table 1 highlights the variability in the prevalence of MVP by different diagnostic methods. MVP is classified as an inheritable connective tissue disorder that is regarded as an autosomal dominant disorder with variable penetrance and is divided into primary and secondary MVP. Primary MVP accounts for the vast majority of the cases and many, but not all, of these are associated with myxomatous degeneration of the mitral valve (MV). Secondary MVP is caused by chordae tendineae rupture and/or abnormal left ventricular (LV) wall motion. Potential causes of secondary MVP include coronary artery disease, rheumatic heart disease, cardiomyopathies, and infective endocarditis.9 Also, MVP may be associated with heritable disorders such as the Marfan syndrome, the Ehlers-Danlos syndrome, and other connective tissue disorders in which myxomatous degeneration of the MV is a prominent feature. Variables that decrease LV size can worsen MVP and similarly, variables that increase LV size can mask MVP. LV size is affected by blood volume, body position (supine, standing, etc.), and maneuvers (eg, Valsalva). A decrease in LV volume is the probable cause of the increased incidence of MVP in atrial septal defect and anorexia nervosa.10–12

Distal myocardial protection with intracoronary beta blocker when added to a Gp IIb/IIIa platelet receptor blocker during percutaneous coronary intervention improves clinical outcome†

Objective: The present study tested the hypothesis that intracoronary (IC) propranolol improves clinical outcomes with percutaneous coronary intervention (PCI) when used with background Gp IIb/IIIa receptor blockade. Background: We have previously shown that administration of a relatively large weight‐based IC dose of the beta blocker propranolol before PCI decreases the incidence of post‐PCI myocardial infarction (MI) and improves short‐ and long‐term outcome. It has previously been shown that administration of a Gp IIb/IIIa receptor blocker decreases post‐PCI MI and improves short‐ and long‐term clinical outcome. Methods: Patients undergoing PCI (n = 400) were randomized in a prospective double‐blind fashion to IC propranolol (n = 200) or placebo (n = 200) with eptifibatide administered to all the patients. Myocardial isoform of creatine kinase was measured during the first 24 hr and clinical outcomes at 30 days and 1 year. Results: MI after PCI was seen in 21.5% of placebo and 12.5% of propranolol patients (relative risk reduction 0.42; 95%CI 0.09, 0.63; P = 0.016). At 30 days, the composite end point of death, post‐procedural MI, urgent target lesion revascularization, or MI after index hospitalization occurred in 22.5% of placebo vs. 13.5% of propranolol patients (risk reduction 0.43; 95%CI 0.08, 0.65; P = 0.018). Similar results were observed at 1 year with adverse outcomes in 21.5% of propranolol and 32.5% of placebo patients (P = 0.01). Conclusion: IC propranolol administration with the background Gp IIb/IIIa receptor blockade significantly reduces the incidence of post‐PCI MI and improves the short‐ and long‐term clinical outcome when compared with a Gp IIb/IIIa blocker alone.

Color M-mode flow propagation velocity and conventional Doppler indices in the assessment of diastolic left ventricular function during isometric exercise

Background and objective: Color M‐mode flow propagation velocity (Vp) was shown to be a preload‐independent measure of diastolic function. To study the effects of an increase in afterload induced by isometric handgrip exercise on diastolic function assessment in patients with cardiomyopathy, we measured Vp and conventional Doppler indices at baseline and at 30% of predetermined maximum handgrip strength. Methods: Twenty‐four patients with systolic dysfunction were divided into two groups: Group I comprising 12 patients with E/A < 1 (early filling velocity/atrial contraction velocity) and Group II comprising 12 patients with E/A > 1. All the patients underwent measurement of Vp, E velocity, its deceleration time (DT), A velocity, isovolumic relaxation time (IVRT), and pulmonary atrial flow reversal velocity (PFR) at baseline and at 30% of predetermined maximum handgrip strength. Twelve healthy controls underwent these same measurements. Results: When comparing baseline to peak echocardiographic data, no significant changes were noted in Vp in any of the groups while a shift of pulsed Doppler indices of Group I toward a pattern closer to that of Group II was noted and a decrease in E velocity and E/A ratio with an increase in IVRT occurred in healthy controls. Conclusions: Color M‐mode flow propagation velocity seems to be an afterload‐independent measure of diastolic function in patients with moderate to severe cardiomyopathy while pulsed Doppler indices are more sensitive to loading conditions induced by isometric exercise.

Native Valve Infective Endocarditis: What Is the Optimal Timing for Surgery?

IE remains a dreaded disease masquerading under a myriad of presentations in an evolving epidemiological environment. In our continuing endeavor against this deadly disease, echocardiography has evolved into an indispensable diagnostic tool to define structural complications and guide therapy. Timing of surgical intervention for IE remains a subject of intense debate and depends on the cardiac and systemic complications of the infection, the virulence of the organism, and the responsiveness to medical therapy. A judicious agreement among cardiologist, cardiovascular surgeon, and infectious disease specialist should define whether surgical intervention is warranted and, if so, the optimal timing. Further optimization of guidelines will help in the diagnosis and treatment of endocarditis but will never be a substitute for sound judgment and experience.

Coronary Guidewire Complications

An 86-year-old male presented with unstable angina. Angiography demonstrated a nondominant right coronary artery (RCA), mild obstruction in the left anterior descending (LAD) coronary artery, several lesions of the mid and distal portions of the left circumflex coronary artery (LCX) as well as a lesion in the ostium of a large first obtuse marginal (OM1) branch.1