Parameters Of Left Ventricular Performance Research Articles

Failure of balloon aortic valvuloplasty to result in sustained clinical improvement in patients with depressed left ventricular function

Although balloon aortic valvuloplasty usually results in acute hemodynamic improvement, recurrent symptoms often occur within several months. The current study was designed to determine whether clinical characteristics, including invasive hemodynamic parameters of left ventricular (LV) performance, are predictive of short-term patient outcome. Eighty-one consecutive patients were prospectivety enrolled in the study protocol. High-fidelity dual sensor micromanometer catheters, digital ventriculography and aortography and Fick cardiac output were measured before and immediately after balloon aortic valvuloplasty. Stroke work was defined from pressure-volume loops. The acute hemodynamic results obtained in patients with overall improved symptoms were compared to those with recurrent symptoms at 3 months. Fifty-three patients (65%) were improved at 3-month evaluation (group 1), whereas 28 patients (35%) had either returned to symptoms at baseline (17), had undergone aortic valve replacement (3) or had cardiac death (8). Compared to patients with improved symptoms, patients with recurrent symptoms demonstrated a tower cardiac output, higher LV end-systolic volume, decreased LV ejection fraction, diminished LV stroke work and decreased LV peak positive dP/dt. The final aortic valve area and change in aortic valve area did not predict which patients would develop recurrent symptoms. Stepwise logistic regression revealed that LV ejection fraction was the only independent predictor of overall status at 3 months (p = 0.002). Eighty-four percent of patients with an ejection fraction >;45% were improved. In the group with an ejection fraction ≤45%, less than half of the patients demonstrated improved symptoms at short-term followup. Parameters of LV performance can accurately predict short-term patient outcome after balloon aortic valvuloplasty. Because patients with depressed baseline LV function are much less likely to have improved symptoms compared to patients with preserved LV performance, the clinical outcome of balloon aortic valvuloplasty appears primarily related to underlying LV function rather than any measurable change during the procedure.

Evaluation of long-term variance of left ventricular performance indexes in closed-chest dogs.

To assess the long-term variance of several parameters of left ventricular performance, we evaluated maximum rate of pressure development (dP/dtmax), ejection fraction, mean velocity of circumferential fiber shortening (VCF), the slope and volume-axis intercept of the end-systolic pressure-volume (PES-VES) relation, the stroke-work end-diastolic volume (SW-EDV) relation, and the dP/dtmax-EDV relation in six chronically instrumented dogs. Each dog was studied five times over a period of 3 wk in the conscious autonomically intact state, after autonomic blockade, and after administration of anesthesia. For each index under each set of testing conditions, a coefficient of variation was determined, defined as (SD/mean) x 100, and expressed as a percent. In conscious autonomically intact dogs, a low day-to-day variance was present in dP/dtmax (6.4%), ejection fraction (6.8%), mean VCF (6.5%), and the slope and volume intercept of the SW-EDV relation (7.2 and 6.2%), whereas higher variance was seen in the slope and intercept of the PES-VES relation (18.1 and 36.1%). The highest variance was present in parameters of the dP/dtmax-EDV relation. Thus dP/dtmax, ejection fraction, and the slope and volume intercept of the SW-EDV relation may be the most reliable indexes for long-term evaluation of left ventricular performance.

Alteration of diastolic filling rate during exercise radionuclide angiography: a highly sensitive technique for detection of coronary artery disease.

Diastolic and systolic parameters of left ventricular performance were characterized from high-frequency time-activity curves obtained in 10 normal volunteers (mean age 29 +/- 4 yr), in 25 patients with normal coronary arteries, and in 50 patients with coronary artery disease (CAD) at rest and during three stages of exercise radionuclide angiography. In the normal volunteers ejection fraction was 65 +/- 5% (SD) at rest and 78 +/- 5% with exercise (p less than .001). In patients with normal coronary arteries ejection fraction was 64 +/- 5% at rest and 72 +/- 8% with exercise (p less than .0001). In patients with CAD resting ejection fraction was 60 +/- 10% and that during exercise was 61 +/- 13% (p = NS). Peak diastolic filling rate in the first half of diastole, peak systolic ejection rate, and times to peak rates and to end-systole were measured. In the normal subjects resting peak diastolic filling rate was 3.1 +/- 0.6 end-diastolic counts/sec and it increased in all subjects with exercise to 3.6 +/- 0.7 (p less than .05). In patients with normal arteries and those with CAD peak diastolic filling rate was 2.3 +/- 0.8 at rest and with exercise this parameter increased to 3.2 +/- 1.1 (p less than .001) in patients with normal arteries and fell to 1.7 +/- 0.6 in those with CAD (p less than .001). Peak systolic ejection rate decreased from 2.5 +/- 0.8 to 1.9 +/- 0.8 with exercise in patients with CAD (p less than .001).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac size and function in Paget's disease of bone

We performed non-invasive assessment of cardiac size and function by clinical criteria, standard electrocardiography, chest X-ray, systolic time intervals and echocardiography in 27 patients with Paget's disease of bone and in 20 control subjects. The patients were divided into two groups on the basis of the degree of skeletal involvement (< 15% in Group I and > 15% in Group II). No differences in heart size parameters of left ventricular performance were noted between Group I and controls. Cardiomegaly, increased left ventricular diastolic dimension and increased left ventricular mass indicative of ventricular hypertrophy were found in Group II compared to control subjects. In addition, patients with more extensive skeletal involvement had signs of depressed myocardial contractility, increased left ventricular volumes in diastole and systole and enlarged stroke volume, with no differences in echographic cardiac output compared to Group I and controls. The findings show an above normal incidence of cardiac enlargement and disturbed left ventricular performance in patients with Paget's disease and osseous lesions in > 15% of skeleton. The clinical implications of the altered cardiac function in patients with Paget's disease are briefly discussed.

Radionuclide evaluation of left ventricular function with nonimaging probes

Portable nonimaging probes have been developed that can evaluate left ventricular function using radionuclide techniques. Two modes of data acquisition are possible with these probe systems, first-pass and gated. Precordial radiocardiograms obtained after a bolus injection can be used to determine cardiac output, pulmonary transit time, pulmonary blood volume, left ventricle ejection fraction, and left-to-right shunts. Gated techniques can be used to determine left ventricular ejection fraction and sytolic time intervals. Probe-determined indices of left ventricular function agree excellently with comparable measurements determined by conventional camera-computer methods as well as by invasive techniques. These have begun to be used in a preliminary manner in a variety of clinical problems associated with left ventricular dysfunction. This review discusses the types of probe systems available, the methods used in positioning them, and details the specifics of their data acquisition and processing capacity. The major criticisms of probe methods are that they are nonimaging and that they measure global rather than regional left ventricular function. In spite of these criticisms, probe systems, because of their portability, high sensitivity, and relatively low cost are useful supplements to conventional camera-computer systems for the measurement of parameters of left ventricular performance using radionuclide techniques.