Change in filling pattern with preload reduction reflects left ventricular relaxation

Respiratory changes in the E/A wave pattern can be an early sign of diastolic dysfunction: an echocardiographic long-term follow-up study

BACKGROUND

The left ventricular filling pattern may show changes during respiration, which are generally used in the diagnosis of diastolic dysfunction. The clinical importance of the respiratory E/A wave pattern change has been investigated in a limited number of studies. The aim of the present study was to assess the diastolic function of hypertensive patients with respiratory changes in mitral flow over a long-term follow-up period.

MATERIAL/METHODS

Our study included 107 newly diagnosed and untreated hypertensive patients (49 males; mean age, 46±10 years) with respiratory changes during transthoracic echocardiography (TTE). In addition, the patient group was classified into 2 groups according to the change in E/A pattern by the Valsalva maneuver. After a mean follow-up period of 44±7 month, 90% of the hypertensive patients and the entire control group were re-examined.

RESULTS

Relaxation abnormalities developed in 84% of the patients (58/80) in the Valsalva-positive group after the follow-up period. The frequency of relaxation abnormalities was 60% in the Valsalva-negative group and 3.1% in the control group (p<0.001). Based on multivariate regression analysis, the echocardiographic predictors of the development of relaxation impairment were mitral E velocity, A velocity, deceleration time, isovolumetric contraction time, E/E' ratio, and the presence of respiratory change. The most important parameter for the development of an abnormal relaxation pattern was the presence of respiratory change after adjustment according to the changes with the Valsalva maneuver.

CONCLUSIONS

Respiratory change in mitral flow can be evaluated as an early sign of diastolic dysfunction in patients with hypertension.

Load-independent index of diastolic filling: model-based derivation with in vivo validation in control and diastolic dysfunction subjects

Maximum elastance is an experimentally validated, load-independent systolic function index stemming from the time-varying elastance paradigm that decoupled extrinsic load from (intrinsic) contractility. Although Doppler echocardiography is the preferred method of diastolic function (DF) assessment, all echo-derived indexes are load dependent, and no invasive or noninvasive load-independent index of filling (LIIF) exists. In this study, we derived and experimentally validated a LIIF. We used a kinematic filling paradigm (the parameterized diastolic filling formalism) to predict and derive the (dimensionless) dynamic diastolic efficiency M, defined by the slope of the peak driving force [maximum driving force (kx(o)) proportional, variant peak atrioventricular (AV) gradient] to maximum viscoelastic resistive force [peak resistive force (cE(peak))] relation. To validate load independence, we analyzed E-waves recorded while load was varied via tilt table (head up, horizontal, and head down) in 16 healthy volunteers. For the group, linear regression of E-wave derived kx(o) vs. cE(peak) yielded kx(o) = M (cE(peak)) + B, r2 = 0.98; where M = 1.27 +/- 0.09 and B = 5.69 +/- 1.70. Effects of diastolic dysfunction (DD) on M were assessed by analysis of preexisting simultaneous cath-echo data in six DD vs. five control subjects. Average M for the DD group (M = 0.98 +/- 0.07) was significantly lower than controls (M = 1.17 +/- 0.05, P < 0.001). We conclude that M is a LIIF because it uncouples intrinsic DF (i.e., the pressure-flow relation) from extrinsic load (left ventricular end-diastolic pressure). Larger M values imply better DF in that increasing AV pressure gradient results in relatively smaller increases in peak resistive losses (cE(peak)). Conversely, lower M implies that increasing AV gradient leads to larger increases in resistive losses. Further prospective validation characterizing M in well-defined pathological states is warranted.