Doppler-derived left ventricular negative dP/dt as a predictor of atrial fibrillation or ischemic stroke in patients with degenerative mitral regurgitation and normal ejection fraction

Rate of left ventricular pressure change by Doppler echocardiography in dogs with chronic mitral valve disease at different stages of congestive heart failure

Although the major pathological feature of chronic mitral valve disease is mitral regurgitation, myocardial dysfunction has been suggested to be present in dogs with chronic mitral valve disease. However, accurate assessment of myocardial function remains challenging. Doppler-derived rate of left ventricular pressure change is a simple, less load-dependent method for evaluating myocardial function. We aimed to evaluate Doppler-derived rate of left ventricular pressure change for assessing myocardial function in different stages of dogs with chronic mitral valve disease. This analytical cross-sectional study recruited 55 client-owned dogs with chronic mitral valve disease prospectively. Based on physical examination, indirectly measured blood pressure, routine hematologic and biochemistry examinations, thoracic radiography, electrocardiography, and echocardiography, dogs were diagnosed as mitral valve disease and excluded for systemic diseases and other cardiac diseases. They were classified according to the International Small Animal Cardiac Health Council scales. Doppler-derived rates of left ventricular pressure rise and fall (dP/dt and -dP/dt) were analyzed by two investigators using continuous-wave Doppler imaging. Doppler-derived dP/dt was higher in dogs of class III_a than in those of the other classes, whereas values of -dP/dt decreased significantly with the severity of congestive heart failure. The peak velocity of the early diastolic wave and -dP/dt were identified as independent predictors of congestive heart failure. Our findings suggested that Doppler-derived dP/dt and -dP/dt, used in combination with conventional echocardiographic variables, could allow a better understanding of myocardial dysfunction and a possibility for prediction of the risk of heart failure in dogs with chronic mitral valve disease.

Diagnosing Paroxysmal Atrial Fibrillation: Are Biomarkers the Solution to This Elusive Arrhythmia?

Atrial fibrillation (AF) is the commonest sustained arrhythmia globally and results in significantly increased morbidity and mortality including a fivefold risk of stroke. Paroxysmal atrial fibrillation (PAF) constitutes approximately half of all AF cases and is thought to represent an early stage of the disease. This intermittent form of atrial arrhythmia can be a challenge to identify and as a result many affected individuals are not prescribed appropriate antithrombotic therapy and hence are at risk of stroke and thromboembolism. Despite these adverse outcomes there have been relatively few diagnostic advances in the field since the introduction of the Holter monitor in 1949. This review aims to establish the available evidence for electrophysiological, molecular, and morphological biomarkers to improve the detection of PAF with reference to the underlying mechanisms for the condition.

Echocardiographically derived effective valve opening area in mitral prostheses: a comparative analysis of various calculations using continuity equation and pressure half time method

Detection of dysfunctional mitral valve prostheses (MP) remains complex even though being optimized by considering echocardiographically derived prosthetic effective orifice area (VA). The purpose was to compare VA in MP, calculated by the continuity equation (CE) using peak velocities (CEVpeak), mean velocities (CEVmean), velocity-time integrals (CEVTI) and the pressure half time method using 220 ms as constant first (PHT220) as well as optimized constants. In 267 consecutive patients with normally functioning MP, we investigated VA within the first postoperative month. With increasing prosthetic sizes, mean VA values also increase in all calculations. The statistical curves demonstrate no significant difference in graphical steepness but show different levels. Comparison of mean VA showed the known systematic higher values of PHT220 and significantly decreased results when using CEVTI. This systematic difference between mean VA applying PHT220 versus CEVTI is approximately 1.0 cm(2) for all prosthetic sizes. Calculations via CEVpeak were close to the results of CEVTI. CEVmean produced values, which graphically correspond to the PHT220 curve. Only PHT220 detected the constructional equal prosthetic inner ring width between 29 and 31 mm. To compensate the systematic difference between CEVTI and PHT220, an optimized constant of 140 ms was calculated to be applied in PHT (PHT140). VA is a robust and, therefore, preferable parameter for investigating MP. If needed, both CE and PHT are applicable with a systematical difference between CEVTI and PHT220. An optimized constant of 140 ms (PHT140) should be applied when calculating VA of mitral valve prostheses via PHT.