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Diastolic Heart Failure – part 5

Theo các tiêu chuẩn đề xuất của Tập đoàn Nghiên cứu châu Âu về suy tim tâm trương, chẩn đoán suy tim tâm trương (DHF) là dựa trên sự hiện diện của một bộ ba của các dấu hiệu hoặc triệu chứng của suy tim sung huyết | 9 Invasive Evaluation of Diastolic Left Ventricular Dysfunction Loek van Heerebeek and Walter J. Paulus Introduction According to the criteria proposed by the European Study Group on Diastolic Heart Failure the diagnosis of diastolic heart failure DHF is based on the presence of a triad of signs or symptoms of congestive heart failure a normal left ventricular LV ejection fraction and objective evidence of diastolic LV dysfunction.1 Objective evidence of diastolic LV dysfunction can be obtained using invasive techniques or noninvasive imaging. Because of questionable sensitivity of noninvasive techniques such as Doppler mitral flow velocity measurements some investigators proposed restricting the diagnosis of definite DHF only to those patients who had invasive evidence of diastolic LV dysfunction.2 Acquisition of objective evidence of diastolic LV dysfunction by invasive techniques therefore remains important. This objective evidence can consist of an assessment of LV relaxation kinetics or an assessment of LV diastolic distensibility. It requires use of high-fidelity tip-micromanometer catheters to measure LV cavity pressures and LV conductance catheters or LV angiograms to simultaneously measure LV cavity dimensions. If the LV diastolic distensibil-ity assessment is intended to derive myocardial stiffness indices regional LV stress and strain values need to be determined and the LV pressure and volume measurements therefore need to be implemented with an LV wall thickness measurement usually derived from a simultaneously acquired two-dimensional echocardiogram.3 Left Ventricular Relaxation Kinetics LV dP dtmin is afterload sensitive. The time constant of LV pressure decay tau is less afterload sensitive. Calculation of tau has to take into consideration the closeness of an exponential fit the start and end point of the fit and the asymptote pressure of the fit. Left ventricular relaxation kinetics can be assessed invasively by LV peak negative dP dt LV dP dtmin