2 New Measurements Used to Describe the Filling Phase of the Left Ventricle (LV).

Overview

As we live longer our population experiencing heart failure (HF) continues to grow consuming an increasing percent of healthcare dollars. Systolic heart failure or pump failure is easy to recognize and measure and is expressed as ejection fraction. Diastolic heart failure (DHF) or failure to fill adequately is much more difficult to quantify with no single measure or number being used to express the severity instead groupings are used with normal and Grade I, II or Grade III to classify with Grade III being the direst. Heart Failure with Reduced Ejection Fraction (HFrEF) and Heart Failure with Preserved Ejection Fraction (HFpEF) are used to identify the primary clinical presentation of HF but do not adequately describe the combined effect often presenting within the same subject. It is estimated 35 to 50% of those with HFrEF, having Left Ventricle Ejection Fraction (LVEF) \< 50%, and 50 to 70% of those with HFpEF, having ejection fraction ≥ 50%, also have moderate to severe diastolic dysfunction (DD). The purpose of this study is two fold. The first is to determine if the rate of change measured from the left ventricular inflow inspiratory phase Doppler waveform provides insight into a cause of diastolic heart failure by comparing echocardiographic data points obtained prior to and immediately following optimization of a bi-ventricular pacemaker. This HF population requires an ejection fraction of 35 percent or lower to qualify for the device. These echocardiograms have been previously completed and will be reanalyzed. The second purpose is to determine if relationships between different features of a LV volume curve can be used to generate a single number to describe global diastolic function using the same echocardiograms from the pacemaker group. Results will be compared to a small group of healthy normal participants as a control for validation.

The purpose of this study is to introduce novel measurements to improve the classification of ventricular diastolic performance. There are 2 cohorts. Cohort 1 consists of 100 subjects who were referred and received echo guided biventricular pacemaker optimization. This retrospective component data is being retrieved to compare baseline and final cardiac performance measures. Comparisons will be made between Doppler and 3D echo diastolic and systolic markers. The Doppler diastolic markers will include D-E slope measuring the rate of pressure equalization between the left atrium (LA) and left ventricle (LV) during inspiration and expiration. MV VTI, the velocity time integral of the left ventricular inflow tract (LVIT) a surrogate measure for LV filling volume, averaging three consecutive complexes and minimal and maximal variability. TDI, tissue Doppler Imaging, when coupled with LVIT measures provides an estimation of left ventricular diastolic pressure. IRT, isovolemic relaxation time, an indicator of LA preload, S/D ratio, an indicator of LA compliance/pressure compared to pulmonary venous pressure. LAv, LA volume, a criteria for diastolic dysfunction grading. TRvmax, tricuspid regurgitation maximum velocity, used to estimate right ventricular systolic pressure. 3D measures will be obtained from the volume curve generated from the 3D full volume image acquisition. The 2 slopes being compared are the initial filling (R1) and intermediate filling (R2) rates of volume change over time or R1/R2. LV ejection fraction, diastolic filling time (DFT), ejection time (ET), heart rate (HR), initial filling time (IFT), and stroke volume (SV) are all being measured from the 3D volume curve. Cohort 2 consists of normal healthy participants to serve as a comparison providing HF diseased state differentiation. All baseline measures performed in cohort 1 will be done for cohort 2. Primary Objective/Aim/Goal/Hypothesis Hypothesis: To determine if LV volume curves can be used to generate a single number that globally describes diastolic function and identify relationship to current grouping algorithm. Secondary Objective/Aim/Goal/Hypothesis Hypothesis: To determine if the pulse wave Doppler of the left ventricular inflow tract D-E slope measure and changes correlate with changes in diastolic performance of the LV. Hypothesis: Does weighting of the volume curve analysis with various features of the curve such as stroke volume, initial filling volume, and initial filling volume percent provide greater sensitivity or specificity in differentiating diastolic performance. Study Design: This study is a retrospective observational data analysis of echocardiographic images and Doppler waveforms comparing data between measurements and calculations taken at baseline and after final programming of biventricular pacemaker devices performed during a single visit. Additionally, the echo data from 5 normal healthy participants will be acquired during a single visit to establish normal values and demonstrate reproducibility.