Mohsen S. Alharthi

The Metabolic Syndrome and Cardiovascular Disease: Part 2

In part 1 of this overview, the authors reviewed the epidemiology, definitions, pathophysiology, and interaction of inflammatory markers that are elaborated from the very active paracrine adipocyte. In part 2, they focus on the management of the metabolic syndrome. Management of this syndrome includes identification of individuals in the early stages of the syndrome and emphasizes the risk of developing diabetes mellitus and the progression to cardiovascular disease. This can be accomplished by simple physical examination and an assessment of routine laboratory findings, which should include measurement of fasting glucose, a lipid profile, and body morphometrics. A 10-year risk assessment is needed in patients who have a diagnosis of the metabolic syndrome. The most important therapeutic intervention in the metabolic syndrome is lifestyle change, with a focus on weight reduction and regular leisure time physical activity.

Impact of acute moderate elevation in left ventricular afterload on diastolic transmitral flow efficiency: analysis by vortex formation time.

BACKGROUND The formation of a vortex alongside a diastolic jet signifies an efficient blood transport mechanism. Vortex formation time (VFT) is an index of the optimal conditions for vortex formation. It was hypothesized that left ventricular (LV) afterload impairs diastolic transmitral flow efficiency and therefore shifts the VFT out of its optimal range. METHODS In 9 open-chest pigs, LV afterload was elevated by externally constricting the ascending aorta and increasing systolic blood pressure to 130% of baseline value for 3 minutes. RESULTS Systolic LV function decreased, diastolic filling velocity increased only during the late (atrial) phase from 0.46 +/- 0.06 to 0.63 +/- 0.19 m/s (P = .0231), and end-diastolic LV volume and heart rate remained unchanged. VFT decreased from 4.09 +/- 0.27 to 2.78 +/- 1.03 (P = .0046). CONCLUSION An acute, moderate elevation in LV afterload worsens conditions for diastolic vortex formation, suggesting impaired blood transport efficiency.

Epicardial fat and its association with cardiovascular risk: a cross-sectional observational study.

Background: The association between visceral obesity and cardiovascular risk has been well described. Some studies show a proportional relationship between the presence of visceral obesity and epicardial fat. Measuring the amount of epicardial adipose tissue (EAT) can be a novel parameter that is inexpensive and easy to obtain and may be helpful in cardiovascular risk stratification. However, the relationship between epicardial fat and cardiac function and that between epicardial fat and cardiac risk factors is less well described. Objectives: To evaluate the association between echocardiographic epicardial fat and the morphologic and physiologic changes observed at echocardiography and to evaluate the association between epicardial fat and cardiac risk factors. A cross-sectional study of 97 echocardiographic studies (females, n = 42) was conducted. Two groups were identified: epicardial fat ≥ 5 mm (group I) and <5 mm (group II). Results: Epicardial fat >5 mm was associated with LA enlargement, with lower ejection fraction, increased left ventricular mass, and abnormal diastolic function. On a multivariable regression analysis, all these parameters also correlated individually with EAT thickness independent of age. Hyperglycemia (DM), systolic hypertension, and lipid parameters for metabolic syndrome showed a trend for positive association, but this was not statistically significant. The association was not significant even for higher cutoff limits of EAT thickness. Conclusion: Epicardial fat >5 mm is associated with cardiac abnormalities on echocardiography. This is a sensitive assessment of body fat distribution, is easily available at echocardiography, and is simple to acquire at no added cost. Further studies looking at the appropriate cut-off thickness of EAT and the sites of measurement to be used are needed. Comparison of this simple and inexpensive measure with other measures of obesity, such as waist-hip ratio, body mass index, Dexa scan of visceral fat, and magnetic resonance imaging of visceral, are needed.

Parachute Mitral Valve in Adults—A Systematic Overview

Parachute mitral valve (PMV) is a rare congenital anomaly of the mitral valve apparatus seen in infants and young children. In most instances PMV is associated with other congenital anomalies of the heart, in particular obstructive lesions of the mitral inflow (mitral valve ring) and left ventricular outflow tract (subaortic stenosis), and coarctation of aorta and is referred to as Shones complex or Shones anomaly. PMV may also occur as an isolated lesion or in association with other congenital cardiac anomalies. Not much is known about PMV in adults as an isolated anomaly or in association with other congenital cardiac anomalies. We reviewed the literature to identify cases of PMV (isolated or associated with other lesions) in adults, to address prevalence, clinical presentation, diagnosis, treatment, and outcome of such patients. (Echocardiography 2010;27:581‐586)

Right ventricular free wall circumferential strain reflects graded elevation in acute right ventricular afterload

This study was designed to evaluate the concurrent changes in the right ventricular free wall (RVFW) movement in experimentally induced, acute mild, moderate, and severe right ventricle (RV) afterload conditions. In 14 open-chest pigs (weight 43 +/- 4 kg) with preserved pericardia, acute mild (>35 and <50 mmHg), moderate (> or =50 and < or =60 mmHg), and severe (>60 mmHg) increases in RV systolic pressure (RVSP) were induced by constriction of the pulmonary artery. At each step, longitudinal, radial, and circumferential strains and strain rates were measured in both the RVFW and the interventricular septum. The mean RVSPs were 31.0 +/- 4.3 mmHg at baseline and 41.1 +/- 2.7 mmHg during mild, 52.7 +/- 3.4 mmHg during moderate, and 61.7 +/- 1.6 mmHg during severe afterload conditions. The RVFW circumferential strains showed significant differences among baseline, mild, moderate, and severe afterload conditions (-10.5 +/- 3.9, -8.3 +/- 3.3, -5.4 +/- 2.7, and -7.5 +/- 5.3%, respectively, P = 0.008) and had significant linear correlation with RVSP (r = 0.636, P < 0.001) if the severe condition was excluded. Decrease of the RVFW circumferential strain magnitude is the most distinct response in acute mild and moderate RV afterload that could aid in detection of clinical conditions associated with acutely increasing RV afterload.

Global left atrial dysfunction and regional heterogeneity in primary chronic mitral insufficiency

AIMS We assessed the hypothesis that global and regional left atrial (LA) function is altered in patients with chronic primary mitral regurgitation (MR) secondary to myxomatous mitral valve disease (MMVD). METHODS AND RESULTS Velocity vector imaging of the LA was acquired from apical four- and two-chamber views in 41 normal and 43 subjects with chronic MR due to MMVD. All had normal left ventricular systolic function. The LA subendocardium was traced to obtain atrial volumes, ejection fraction, velocities, and strain (ε)/strain rate (SR) measurements. To explore the effects of MR severity on LA function, subjects were divided into two groups: mild vs. moderate/severe MR. Reservoir (expansion and diastolic emptying indices), booster pump (active emptying index) functions, and LA ejection fraction were markedly impaired in subjects with MR (P < 0.001). Mean LA ε was reduced in moderate/severe MR compared with control subjects (P < 0.01). A consistent pattern of differences in atrial regional function was noted with the anterior wall having a lower peak systolic ε/SR, which is more evident in the moderate/severe MR group (P < 0.01) when compared with controls and mild MR groups. CONCLUSION LA filling during ventricular systole (reservoir function), LA contraction (booster pump function), and ejection fraction were significantly impaired in patients with chronic MR. Regional differences in LA contractility at the anterior wall were noted presumably due to the eccentricity of the systolic anteriorly directed MR jet hitting the anterior wall and altering local wall mechanics.

Selective echocardiographic analysis of epicardial and endocardial left ventricular rotational mechanics in an animal model of pericardial adhesions

AIMS Diagnosis of pericardial adhesions is challenging. Twisting of the left ventricle (LV) is essential for normal LV functioning. We experimentally characterized the impact of pericardial adhesions on epicardial and endocardial LV rotational mechanics with velocity vector imaging (VVI). METHODS AND RESULTS In nine open-chest pigs, the heart was exposed while preserving the pericardium. Early-stage pericardial adhesions were simulated by instilling tissue glue to pericardial space. Using VVI, LV rotational mechanics was quantitatively assessed endocardially and epicardially along with haemodynamic data at baseline and following the experimental intervention. End-diastolic volume, ejection fraction, stroke volume, late diastolic filling velocity, and LV endocardial torsion decreased significantly. LV epicardial torsion showed only a trend towards decrease (P = 0.141). Endocardial twist and torsion decreased significantly (P = 0.007) from 8.6 +/- 2.2 degree and 1.497 +/- 0.397 degree/cm to 5.3 +/- 1.8 degree and 0.97 +/- 0.38 degree/cm, respectively; epicardial twist showed a trend towards a decrease in its magnitude. Gradients of endocardial/epicardial twist and torsion did not significantly change. CONCLUSION The model suggests that early-stage pericardial adhesions reduce both epicardial and endocardial LV twist and torsion without a significant alteration in their transmural gradient. Selective endocardial/epicardial analysis of LV twisting mechanics may have a diagnostic role in detection of early formation of pericardial adhesions.

Evaluation of left ventricular rotation in obese subjects by velocity vector imaging

AIMS Obesity is a well-known risk factor in the development of cardiovascular disease. We hypothesize that early left ventricular (LV) dysfunction secondary to obesity could be signalled by abnormal LV rotation. METHODS AND RESULTS This prospective study examined 60 subjects divided into two groups: obese group with body mass index (BMI) >or=30 and control group with BMI <25. The peak rotation, twist, and torsion of the left ventricle were studied in obese and control subjects, using velocity vector imaging. Age and gender were comparable between the two groups. Obese subjects had higher BMI, waist circumference, fasting glucose, triglycerides, systolic and diastolic blood pressure, low-density lipoprotein cholesterol, and lower high-density lipoprotein cholesterol (P < 0.05). In obese subjects, LV mass and LV mass index were increased, and the ratio of mitral early and late diastolic filling velocity was decreased (P < 0.05). In obese subjects, the peak twist and torsion of the left ventricle displayed a lower trend, and the peak rotation of the left ventricle apex decreased significantly (3.81 +/- 2.09 degrees vs. 5.77 +/- 3.27 degrees , P < 0.001). CONCLUSION Obesity was associated with changes in LV rotation. Velocity vector imaging is a feasible and reproducible echocardiographic technique for the detection of early subclinical LV dysfunction.

Prediction of incipient left ventricular dysfunction in patients with chronic primary mitral regurgitation: a velocity vector imaging study.

AIMS Progressive left ventricular (LV) dilatation and irreversible myocardial damage are important causes of morbidity and mortality in patients with chronic primary mitral regurgitation (MR) due to myxomatous mitral valve disease. We assessed the hypothesis that early subclinical LV dysfunction secondary to chronic primary MR could be signalled by abnormal LV rotation mechanics, utilizing velocity vector imaging (VVI). METHODS AND RESULTS Forty-three with chronic primary MR and 41 normal subjects were evaluated. All had normal LV systolic function. Peak endocardial and epicardial rotations in systole were measured in apical and basal short-axis images. LV twist was defined as the net difference between apical and basal angles of rotation while LV torsion was calculated as LV twist divided by LV diastolic longitudinal length. To explore the effects of MR severity on LV rotation, patients were divided into three groups: mild, moderate, and severe MR. The peak twist and torsion of the LV endocardium displayed significant differences across the study groups (P = 0.005 and 0.015, respectively). Subjects with moderate MR revealed the highest LV rotation profile (2.26 ± 0.66°/cm and 17.83 ± 5.2° for torsion and twist, respectively), implicating hyperdynamic LV function. However, severe MR group showed the lowest LV rotation profile (1.39 ± 0.8°/cm and 11.43 ± 6.09° for torsion and twist, respectively), suggesting incipient LV dysfunction. There were no significant differences in epicardial LV rotations. CONCLUSION Evaluation of global LV function by VVI is a novel reproducible index for detecting subnormal latent LV dysfunction in chronic MR patients, which may aid in the optimal timing of surgery.

Multimodality imaging showing complete cardiovascular involvement by Erdheim-Chester disease.

Erdheim-Chester disease (ECD) is a multisystem non-Langerhans form of cell histiocytosis. Histiocytic infiltration leads to xanthogranulomatous infiltrates of multiple organ systems. Erdheim-Chester disease was first reported in 1930, only 320 cases reported in the literature. Cardiac involvement in ECD carries worst prognosis beside the central nervous system. We report the first case with pan-cardiac involvement diagnosed with multimodality imaging.