Volume atrial esquerdo como índice de função diastólica

Abstract

Congestive heart failure (CHF) is one of the main causes of death and hospital admissions in our country, according to data from Datasus 1 . This clinical syndrome is progressive and characterized by complex cardiac and systemic adaptations, which vary during disease evolution 2 .It has been observed, however, that in approximately 30% to 50% of the individuals who develop CHF, the systolic function estimated through the left ventricular ejection fraction (LVEF) is normal or relatively normal 3 . Thus, the cause of cardiac decompensation in these patients is the left ventricular diastolic dysfunction, justifying the term "diastolic cardiac failure" 4 .Little is known on the natural history of this disease, particularly regarding the mechanisms causing affected patients' death 5 , although its prevalence is known among certain groups, such as the elderly and women, as well as the fact that it usually precedes the systolic dysfunction in most cardiac affections, including Chagas' myocardiopathy .There have been few studies published in literature regarding the incidence of CHF in patients with diastolic dysfunction evidenced by Doppler echocardiography. It has been demonstrated, in a population of individuals older than 65 years with no clinical evidence of cardiac disease, that the detection of this type of dysfunction through Doppler echocardiography has a predictive value for the development of CHF in 11 a 15% of the cases within a five-year period 10 . DIASTOLE AND TYPES OF DIASTOLIC DYSFUNCTIONAccording to the most generally employed clinical concept 11 , the diastolic phase of the cardiac cycle, starting with the closing of the semilunar valves, comprises the largest part of the active ventricular relaxation, with periods of isovolumetric relaxation, and rapid ventricular filling, as well as diastasis or passive filling and, finally, the period that involves atrial contraction. The illustration of this concept is depicted in Figure 1.Even though several independent factors affect the diastolic properties of the left ventricle (LV) its actions converge to the transmitral pressure gradient, which, in fact, is the physical determinant of the left ventricular filling 12 .During the isovolumetric relaxation period, the LV behaves as an isolated chamber, as the aortic and mitral valves are closed; thus, its volume is not altered when there is a progressive decrease of intracavitary pressure. The heart relaxation is also the main determinant of the rapid ventricular filling, which is caused by the opening of the mitral valve as a result of the pressure decrease inside the LV, which is lower than that observed in the left atrium (LA) 13 . It is an energy-dependent process, which corresponds to the active sequestration, contragradient, of calcium ions released from troponin during the contractile activation 14 .The rapid ventricular filling, which under normal circumstances is responsible for 80% of the ventricular filling, is also due to the pressure in the left atrium at the moment of the mitral valve opening (pre...

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“…The increase in the A wave probably culminates in a higher velocity of transmitral flow during the end diastole. Furthermore, the evaluation of the LA is also a way to determine the severity of diastolic dysfunction [59], which in turn corroborated our morphological findings, which showed an increase in the weight of the LA in the PSD96 group. During ventricular diastole, the LA is exposed to intraventricular pressure, thus, rises in ventricular filling pressures cause an increase in atrial pressure and consequently atrial remodeling is observed [60].…”

Função diastólica do ventrículo esquerdo em obesos graves em pré-operatório para cirurgia bariátrica

“…It was demonstrated that the greater left atrial volume, the worse the diastolic function, proving the theory that this is a sensitive index that expresses the severity of LV diastolic dysfunction 33 . Left ventricular hypertrophy was more often diagnosed when the LVM criterion was indexed for height (73 patients = 55.3%) than for body surface area (29 patients = 22%), even when following the recent guidelines from the American Society of Echocardiography in that the cutoff for left ventricular mass is greater when indexed for height 9 .…”

Low Prevalance of Major Events Adverse to Exercise Stress Echocardiography

“…Some studies have reported that the size of the left atrium would naturally increase with age. 37 - 39 Thus, senescence would provide changes that would culminate with left atrium dilatation and dysfunction, thus increasing predisposition to atrial arrhythmias, 39 which may influence their occurrence when the patient is submitted to stress, as in ESE. Still with regards to age, this finding as an independent predictor of complications during ESE is very important, considering this is a commonly observed fact in clinical practice.…”