1.
Diastolic stress echocardiography: from basic principles to clinical applications.
Prasad, SB, Holland, DJ, Atherton, JJ
Heart (British Cardiac Society). 2018;(21):1739-1748
Abstract
Heart failure with preserved ejection fraction (HFpEF) looms as a major public heart challenge with increasing prevalence due to an ageing population. Diagnosis can be challenging due to non-specific symptomatology, low natriuretic peptide levels and equivocal diastology on resting echocardiography. Diastolic stress echocardiography represents a non-invasive option to refining the diagnosis in this subset of patients. Diastolic responses to exercise are most commonly measured with a non-invasive measure of left ventricular filling pressures (LVFP) estimated by the ratio of the early mitral inflow wave to early diastolic tissue velocity (E/e' ratio). This is measured pre- and post-exercise , and is highly feasible. An elevation of exercise E/e' >15 is classified as an abnormal response as per current guidelines. An alternative measure of exercise-related diastolic performance, the Diastolic Functional Reserve Index has also been proposed, but has not been as well studied as exercise E/e'. A number of studies have validated exercise E/e' as a measure of LVFP against invasively measured LVFP using simultaneous echocardiography-catheterisation studies. The independent prognostic value of exercise E/e' has also been well delineated in a number of studies. While diastolic stress echocardiography can be considered for all patients with suspected HFpEF, it is of particular value in patients with normal or equivocal diastolic indices on resting echocardiography.
2.
Current noninvasive imaging techniques for detection of coronary artery disease.
Mastouri, R, Sawada, SG, Mahenthiran, J
Expert review of cardiovascular therapy. 2010;(1):77-91
Abstract
The development and widespread use of noninvasive imaging techniques have contributed to the improvement in evaluation of patients with known or suspected coronary artery disease. Stress echocardiography and single-photon computed tomography are well-established noninvasive techniques with a proven track record for the diagnosis of coronary atherosclerosis. These modalities are generally widely available and provide a relatively high sensitivity and specificity along with an incremental value over clinical risk factors for detection of coronary artery disease. PET has a high diagnostic performance but continues to have limited clinical use because of the high expense of the dedicated equipment and difficulties in obtaining adequate radionuclides. Cardiac MRI and multislice computed tomography constitute the most recent addition to the cardiac imaging armamentarium. Cardiac MRI offers a comprehensive cardiac evaluation, which includes wall-motion analysis, myocardial tissue morphology, rest and stress first-pass myocardial perfusion, as well as ventricular systolic function. Cardiac computed tomography allows coronary calcium scanning along with noninvasive anatomic assessment of the coronary tree. It can be combined with functional imaging to provide a complete evaluation of the presence and physiological significance of the atherosclerotic coronary disease. No single imaging modality has been proven to be superior overall. Available tests all have advantages and drawbacks, and none can be considered suitable for all patients. The choice of the imaging method should be tailored to each person based on the clinical judgment of the a priori risk of cardiac event, clinical history and local expertise.
3.
An update on contrast echocardiography.
Chelliah, R, Senior, R
Minerva cardioangiologica. 2009;(4):483-93
Abstract
Ultrasound contrast agents, used with contrast-specific imaging techniques, have an established role for diagnostic cardiovascular imaging in the echocardiography laboratory. The advent of tissue harmonic imaging, albeit a significant advancement in ultrasound technology, still fail to produce diagnostically useful images in a significant proportion of patients. This therefore, often leads to inaccurate assessment of left ventricular function, neccesitating the use of other more laborious and expensive imaging techniques purely for diagnostic purposes. Historically, contrast agents have not been an integral component of the echocardiography imaging laboratory. However the need for a more robust method for the assessment of left ventricular function facilitated the developement of a unique class of contrast agents composed of microbubbles, which together with ultrasound, produce opacification of the left ventricular cavity, thus enabling accurate quantification of its function. The use of these contrast agents have now gone beyond the assessment of wall motion and function to the assessment of myocardial perfusion. Myocardial contrast echocardiography has enabled the assessment of cardiac anatomy, function and perfusion, all in one sitting, by the bedside. Contrast ultrasound imaging has now been applied to even newer techniques such as real-time three-dimensional echocardiography and is also showing promise in the assessment of carotid ultrasound for intima-media thickness. Contrast agents therefore have a significant role in cardiovascular diagnostics and its use can only improve patient care.