Left atrial function measured by cardiac magnetic resonance imaging in patients with heart failure: clinical associations and prognostic value.

BACKGROUND: Left atrial (LA) volume is an important marker of cardiac dysfunction and cardiovascular outcome in heart failure (HF), but LA function is rarely measured. METHODS: Left atrial emptying function (LAEF), its clinical associations and prognostic value was studied in outpatients referred with suspected HF who were in sinus rhythm and had cardiac magnetic resonance imaging (CMRI). Heart failure was defined as relevant symptoms and signs with either a left ventricular ejection fraction (LVEF) <50% or amino-terminal pro-B-type natriuretic peptide (NTproBNP) >400 pg/mL (or >125 pg/mL if taking loop diuretics). RESULTS: Of 982 patients, 664 fulfilled the HF criteria and were in sinus rhythm. The median (interquartile range, IQR) LAEF was 42 (31-51)% and 55 (48-61)% in patients with and without HF (P < 0.001). Patients with HF in the lowest quartile of LAEF (23%; IQR: 17-28%) had lower LV and right ventricular (RV) EF, and greater LV and RV mass and higher plasma NTproBNP than those in the highest quartile of LAEF (56%; IQR: 53-61%). Log[LAEF] and log[NTproBNP] were inversely correlated (r = -0.410, P < 0.001). During a median follow-up of 883 (IQR: 469-1626) days, 394 (59%) patients with HF died or were admitted with HF and 101 (15%) developed atrial fibrillation (AF). In a multivariable Cox model, increasing LAEF, but not LVEF, was independently associated with survival (HR for 10% change: 0.81 (95%CI: 0.73-0.90), P = <0.001). Increasing age and decreasing LAEF predicted incident AF. CONCLUSIONS: In patients with HF, LAEF predicts adverse outcome independently of other measures of cardiac dysfunction.

Exercise-induced ventricular arrhythmia in coronary cameral fistula: A manifestation of reperfusion injury.

Presentation, Investigation and Management of Coronary fistula and its arrhythmic complications.

Behavior of both epicardial and intramural coronary artery flow velocities in various models of myocardial hypertrophy: role for left ventricular outflow tract obstruction.

BACKGROUND: The assessment of coronary flow velocity is becoming crucial in the diagnosis and management of several cardiac dysfunctions and conventional Doppler echocardiography is currently the technique most widely used for detecting their abnormalities noninvasively. METHODS: We sought to evaluate the differences in coronary flow velocity using conventional transthoracic Doppler echocardiography, measuring both the left anterior descending and such intramural (IM) coronary arteries' flow, among the following 4 categories of patients with myocardial hypertrophy: group A, obstructive hypertrophic cardiomyopathy (n = 12); group B, nonobstructive hypertrophic cardiomyopathy (n = 10); group C, left ventricular hypertrophy (LVH) due to hypertension (n = 10); and group D, LVH due to aortic valve stenosis (n = 10). RESULTS: No significant difference between the 4 groups was found with respect to the left anterior descending velocity. Diastolic peak (P < .01) and mean (P < .05) velocities in the IM arterioles were significantly higher in patients from groups A and D than in groups B and C. At multivariate analysis, both dynamic (group A) and fixed (group D) systolic peak gradients, measured by continuous wave Doppler sampling through the left ventricular (LV) outflow tract or the aortic valve, respectively, were found to be major determinants of the IM diastolic velocity, independently on the LV mass. About 75% of patients with obstructive hypertrophic cardiomyopathy showed IM peak and mean velocity >100 cm/s and >70 cm/s, respectively (P = .005). CONCLUSION: These findings likely suggest [corrected] a role for the LV systolic obstruction within the intricate adaptive mechanisms of coronary blood flow to LVH.

Silent broken heart (Can shortness of breath be the only presentation of myocardial infarction?).

A 55-year-old previously healthy man was referred to our cardiology outpatient department (by the respiratory team) due to shortness of breath that started 2-3 months prior. He suddenly became breathless after changing a car wheel with no other associated symptoms. Specifically, he denied ever having had chest pain. His breathlessness got gradually worse preventing him from performing simple everyday activities, such as climbing stairs, and a couple of weeks before presentation, the patient noticed ankle oedema. He was an ex-smoker and drank 3-4 units of alcohol daily. There was a family history of hypertension. He worked as a contract manager in the construction industry. After clinical examination, a transthoracic echocardiogram was performed and the patient was admitted for further investigations. Clinical examination and investigation confirmed missed myocardial infarction with a complication of ventricular aneurysm. The patient was referred to cardiothoracic surgeons for surgical correction of the defect.

Idiopathic left ventricular apical hypoplasia.

A 46-year-old man was found to have an abnormal ECG taken during a routine health and blood pressure check. His only symptom was non-specific central chest discomfort, unrelated to exertion. His ECG showed sinus rhythm, a normal axis and poor R wave progression across the chest leads and lateral T wave flattening. An echocardiogram showed a dilated left ventricle with a thin and hypokinetic septum bulging to the right. The apex was 'not well seen' but also appeared thin and hypokinetic. The right heart and valves were normal. The patient was further investigated for left ventricular hypoplasia.

Congenital circumflex coronary artery fistulae; presentation and diagnosis.

Small fistulae between coronary arteries and the pulmonary artery are common, but abnormal vascular communications between the coronary arteries and other cardiac structures are rare. They were first described by Krause in 1865. We report two cases of fistulous connexions between the circumflex coronary artery and the coronary sinus.

Detection of coronary stenosis with myocardial contrast echocardiography using regadenoson, a selective adenosine A2A receptor agonist.

AIMS: Regadenoson is comparable to adenosine in pharmacologic radionuclide stress tests but has not been studied with stress myocardial contrast echocardiography. This study assessed the haemodynamic profile and ability of regadenoson, a novel selective A(2A) receptor agonist, to detect coronary artery stenosis during myocardial contrast echocardiography. METHODS AND RESULTS: Myocardial contrast echocardiography was performed to measure myocardial blood volume, myocardial blood flow velocity, and total regional myocardial blood flow before and after administration of regadenoson (5 µg kg(-1), 10 s bolus) in 10 open-chest dogs with mild-to-moderate coronary stenosis that was not flow limiting at rest. Regadenoson decreased blood pressure but did not change heart rate. It increased coronary blood flow significantly (P < 0.05) for 30 min, which was attenuated in proportion to coronary stenosis severity. Whereas myocardial blood volume maximally increased by 0.5-0.75-fold in the control region, it did not change in the region supplied by the non-flow limiting stenosis. Perfusion defects were visually and quantitatively detectable for as long as 10 min after administration of regadenoson. No arrhythmias were noted with regadenoson either prior to or during myocardial contrast echocardiography. CONCLUSION: Regadenoson can be used as a vasodilator stress agent with myocardial contrast echocardiography to detect the presence of physiologically significant coronary stenosis. The optimum time for image acquisition was 3-10 min after drug administration.

Relationship between right ventricular volumes measured by cardiac magnetic resonance imaging and prognosis in patients with chronic heart failure.

AIMS: The aim of this study was to investigate the prognostic impact of right ventricular (RV) size in patients with chronic heart failure. METHODS AND RESULTS: Normal volunteers (n = 80) and patients (n = 380) with left ventricular (LV) ejection fraction <45% on echocardiography and on optimal treatment for heart failure underwent cardiac magnetic resonance imaging with measurement of LV and RV volumes, mass and ejection fraction. The mean and the standard deviation (SD) of the RV end-systolic volume index in normal subjects were used to define the normal range as: mean RV end-systolic volume index +2 SD. Patients with dilated RV (>2 SD beyond the mean) (25%) had more frequent evidence of fluid overload in clinical examination and greater LV dimensions (P < 0.0001). During follow-up (median 45, interquartile range: 28-66 months), 37% of patients with and 24% without RV dilation died (log-rank test = 8.4; P = 0.004). In a multivariable Cox regression model, including 13 other clinical variables, RV (HR: 1.08/10 mL/m(2), 95% CI: 1.00-1.18, P = 0.044), but not LV, end-systolic volume index predicted a worse outcome. CONCLUSION: Twenty-five per cent of patients with heart failure due to LV systolic dysfunction have a dilated right ventricle. Greater RV dimensions predict mortality in patients with chronic heart failure. Treatments aimed at preserving or enhancing RV structure and function, possibly by unloading the RV by reducing pulmonary vascular resistance or left atrial pressure, should be investigated.

Clinical and technical considerations for stress myocardial perfusion imaging with multidetector computed tomography.

Cardiovascular compute tomography (CT) is now a robust tool for the evaluation of coronary artery atherosclerosis and stenosis. A number of single-center studies, and now multicenter trials, have shown that the diagnostic accuracy of this tool compares favorably with the reference standard of conventional coronary angiography. Of course, CT angiography does not allow for the assessment of the functional significance of a given coronary lesion. However, recent reports have shown that myocardial perfusion imaging is possible with CT, opening up the possibility of providing a comprehensive evaluation of both coronary anatomy and physiology with one examination. This article reviews the principles, technical considerations, and the potential of stress myocardial perfusion imaging with CT.

Novel cardiac myosin activators for acute heart failure.

Heart failure remains a leading cause of hospitalisation and death. Treatment of acute heart failure has not improved as rapidly as treatment for chronic heart failure. There are three classes of inotropic agents that are in use at present: the catecholamines, phosphodiesterase inhibitors and calcium sensitisers. Cardiac-specific myosin ATPase activators are a novel class of agents designed to improve myocardial contractility by accelerating the productive phosphate-release step of the crossbridge cycle. This article reviews the mechanism of action of myosin ATPase activators, the results of preclinical and Phase I studies and their potential role in the management of heart failure.

Phasic changes in arterial blood volume is influenced by collateral blood flow: implications for the quantification of coronary stenosis at rest.

BACKGROUND: The systolic to diastolic arteriolar blood volume (aBV) ratio derived using myocardial contrast echocardiography (MCE) can identify the presence of coronary stenosis at rest. There are some patients with moderate to severe coronary stenosis who nonetheless exhibit a normal systolic to disatolic aBV ratio. AIM: To test the hypothesis that collateral blood flow influences the systolic to diastolic aBV ratio. MCE-defined phasic changes in aBV were recorded at baseline and up to 2 degrees of non-critical stenosis in 12 dogs. Measurements were made from MCE-defined collateralised and non-collateralised portions of the left anterior descending arterial bed. RESULTS: Increases in both systolic and diastolic aBV were noted in the non-collateralised region with increasing degrees of stenosis. Although these increases in the absolute values did not reach statistical significance, the systolic to diastolic aBV signal ratio in the non-collateralised bed increased significantly between stages (analysis of variance, p = 0.003). In comparison, in the collateralised bed neither the absolute systolic nor diastolic aBV signals changed with increasing degrees of stenosis. Consequently, the aBV signal ratio between systole and diastole also did not change in this bed. CONCLUSION: Phasic changes in aBV are influenced by the degree of collateral blood flow. Thus, if the region of interest is not placed in the centre of the vascular bed, the degree of stenosis may be underestimated by the systolic to diastolic aBV ratio. On the other hand, as extensive collateralisation may indicate excellent prognosis, this ratio may provide prognostic information independent of the coronary anatomy.