Increase In EDV Research Articles

Neuronal Activity Influences Hemodynamics in the Paraoptic Short Posterior Ciliary Arteries: A Comparison between Healthy and Glaucomatous Subjects

Perfusion of the retina adapts to metabolic demand by neurovascular coupling. The present study was an investigation of the presence of neurovascular coupling in the anterior part of the optic nerve in healthy subjects and patients with glaucoma. Retrobulbar blood flow velocities were determined by color Doppler imaging (CDI). Peak systolic and end diastolic velocities (PSVs and EDVs) in the central retinal artery (CRA) or the short posterior ciliary artery (SPCA) were the primary readout. CDI measurements were performed shortly before, during, immediately after, 60 seconds after, and 120 seconds after a 10-Hz flicker stimulation of the retina. Thirty-five patients with glaucoma and 44 healthy control subjects were included in the study. In the SPCA of healthy control subjects, flicker stimulation led to an increase in PSV from 9.7 +/- 0.8 to 12.5 +/- 0.8 cm/s (P < 0.001; n = 24) and of EDV from 2.4 +/- 0.3 to 3.6 +/- 0.3 cm/s (P < 0.001; n = 24). This effect was not detectable in patients with glaucoma. In the CRA, flicker light led to an increase in EDV from 2.1 +/- 0.2 to 3.0 +/- 0.3 cm/s (P = 0.002; n = 20) in healthy volunteers and from 1.3 +/- 0.2 to 2.0 +/- 0.2 cm/s in patients with glaucoma (P = 0.004; n = 15). PSV was not affected by flicker stimulation in either the healthy volunteers or patients with glaucoma. The data indicate the presence of neurovascular coupling in the vascular bed supplied by the paraoptic SPCA. The response pattern to the flicker stimulus differs between healthy subjects and individuals with glaucoma.

Multidetector computed tomography evaluation of left ventricular volumes: Sources of error and guidelines for their minimization

Although multidetector computed tomography (MDCT) is known to overestimate left ventricular (LV) end-systolic and end-diastolic volumes (ESV, EDV) compared to magnetic resonance imaging reference, the potential sources of error have not been thoroughly investigated. We sought to quantitatively assess the effects of the number of reconstructed phases and number of slices used for volume calculation on the accuracy of LV volume measurements. MDCT images obtained in 28 patients (Philips Brilliance 64) were reconstructed at 10, 20, 33, and 100 phases per cardiac cycle. For each number of phases, ESV was measured between aortic valve closure and mitral valve opening and normalized by reference ESV measured at 100 phases/R-R. Both reference ESV and EDV were measured using 20 and separately 10 fixed-thickness slices. Reproducibility was assessed using repeated measurements. In 16 of 28 patients, the timing of end-systole varied with increasing number of reconstructed phases, resulting in a gradual decrease in ESV from 118 +/- 20% of reference ESV to 100 +/- 0%. Reduction in number of slices caused a significant increase in EDV and ESV (4.2 +/- 3.2% and 6.4 +/- 5.5%, respectively), roughly twice the corresponding intraobserver variability (2.5 +/- 1.5% and 3.8 +/- 2.4%). Misidentification of end-systole due to insufficient number of reconstructed phases significantly affects ESV measurements. Also, the number of slices used for volume calculation affects both ESV and EDV beyond intermeasurement variability. To ensure accurate quantification of LV volumes, reconstruction at time intervals smaller than 5% of the RR-interval (>20 phases/cardiac cycles) and tracing endocardial borders in >10 slices are recommended.

Left Ventricular Remodeling After Anterior Wall Acute Myocardial Infarction in Modern Clinical Practice (from the REmodelage VEntriculaire [REVE] Study Group)

Left ventricular (LV) remodeling after acute myocardial infarction (AMI) has been well described in previous studies. However, there is a paucity of data on the incidence of and risk factors for LV remodeling in modern clinical practice that incorporates widespread use of acute reperfusion strategies and almost systematic use of "antiremodeling" medications, such as angiotensin-converting enzyme inhibitors and beta blockers. We enrolled 266 patients with anterior wall Q-wave AMI who had >or=3 segments of the infarct zone that were akinetic on echocardiography before discharge. Echocardiographic follow-up was performed 3 months and 1 year after AMI. LV volumes, ejection fraction, wall motion score index, and mitral flow velocities were determined in a blinded analysis at a core echocardiographic laboratory. Acute reperfusion was attempted in 220 patients (83%; primary angioplasty in 29% and thrombolysis in 54%). During hospitalization, 99% of patients underwent coronary angiography and 87% underwent coronary stenting of the infarct-related lesion. At 1 year, 95% of patients received an antiplatelet agent, 89% a beta blocker, 93% an angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker, and 93% a statin. Echocardiographic follow-up was obtained in 215 patients. There was recovery in LV systolic function as shown by a decrease in wall motion score index and an increase in ejection fraction. There was a significant increase in end-diastolic volume (EDV; 56.4 +/- 14.7 ml/m2 at baseline, 59.3 +/- 15.7 ml/m2 at 3 months, 62.8 +/- 18.7 ml/m2 at 1 year, p <0.0001). LV remodeling (>20% increase in EDV) was observed in 67 patients (31%). Peak creatine kinase level, systolic blood pressure, and wall motion score index were independently associated with changes in EDV. In conclusion, recent improvements in AMI management do not abolish LV remodeling, which remains a relatively frequent event after an initial anterior wall AMI.

Abnormal response to inotropic stimulation in young asymptomatic type I diabetic patients demonstrated by serial gated myocardial perfusion SPECT imaging

In subjects without underlying cardiac disease dobutamine is known to enhance systolic LV function and LV relaxation. As end-systolic (ES) and end-diastolic (ED) volumes (V) can be derived from gated SPECT we intent to study these volumes and their response to dobutamine in order to have a better understanding of the mechanism by which stroke volume (SV) increases during dobutamine infusion. We intent to do this in normal controls and in young diabetic subjects. After injection of sestamibi, serial gated SPECT were obtained at baseline, and during low doses of dobutamine infusion in 12 asymptomatic type I diabetic patients, and in 12 age matched controls. LV EDV, ESV, SV and EF were calculated with the QGS program. Gated SPECT showed comparable LV EF and SV in both groups at rest. There was a significant increase in LVEF and SV during dobutamine infusion but in the diabetic patients the increase in SV was due to a decrease in ESV from 25+/-5 to 20+/-6 ml/m2 (p=0.002) and no change in EDV. In normal controls, the increase in EF was due to an increase in EDV from 69+/-10 to 73+/-12 ml/m2 (p=0.002) with no significant change in ESV. These data confirm the presence of subclinical abnormalities of diastolic function in asymptomatic type I diabetic patients and show differences in adaptation to inotropic stimulation in order to preserve the increase in stroke volume and LV ejection fraction.

Bioimpedance-derived differences in cardiac physiology during exercise stress testing in low-risk chest pain patients.

Little has been written about the utility of thoracic electrical bioimpedance (TEB)-derived cardiac physiologic variables in evaluating patients with low-risk chest pain syndromes. Noninvasive bioimpedance can monitor cardiac physiology while a patient is performing an exercise stress test. In addition, the demographics of patients with chest pain, the incidence of coronary artery disease (CAD), and the methods used for evaluation have well-documented sex differences. The objectives are to show that there are different cardiac physiologic responses to exercise stress test in Chest Pain Evaluation Unit patients with and without true CAD that could be used to stratify patients and that there is a sex difference in TEB results. Patients 18 to 65 years of age with low-risk chest pain were eligible. Patients were attached to the TEB throughout the exercise stress test procedure. Heart rate (HR) was monitored. Primary dependent variables were TEB-measured cardiac output (CO, L/min) and stroke volume (SV, ml) at peak exercise. Secondary variables were TEB-measured ejection fraction (%), end-diastolic volume (EDV, ml), ventricular ejection time (ms), and thoracic fluid index (omega) at peak exercise. Outcome variables were either proved CAD or patient sex. CAD was proved by angiography, stress scintigraphy, or stress echocardiogram. Results were compared using a Student's t test assuming equal variances, with significance considered at a P < 0.05, and 95% confidence intervals were calculated for significant results. Nine patients had proved CAD, 82 patients did not. Forty-three women and 48 men were included in the study. At peak exercise, patients with CAD had a significantly smaller increase in EDV than patients without CAD (32.8 +/- 59.5 ml versus 89.3 +/- 101.8 ml) without a significant change in CO, SV, or HR. At peak exercise, women had a significantly smaller increase in CO and SV without a significant change in HR. In addition, women had a significantly smaller increase in EDV. When compared with patients without CAD, patients with CAD have a significantly smaller increase in EDV and a trend toward the same effect in CO and SV. Women have significantly smaller increases CO, SV, and EDV compared with men. Because there were no differences in HR, using HR as the sole end point would miss these differences. TEB is a practical means of measuring these variables.

Effect of long-term irbesartan treatment on endothelium-dependent vasodilation in essential hypertensive patients

Endothelial dysfunction plays a pivotal role in the development of essential hypertension and its complications. The purpose of this study is to assess the effect of antihypertensive treatment with the angiotensin receptor blocker irbesartan on endothelial function in a group of essential hypertensive patients. Thirty-two untreated hypertensives are examined at baseline and at the end of a six-month period of irbesartan treatment. Endothelium-dependent and -independent responses are determined by measuring changes in forearm blood flow (FBF) by strain gauge plethysmography in response to intrarterial infusions of acetylcholine (endothelium-dependent vasodilation [EDV]), sodium nitroprusside (endothelium-independent vasodilation [EIV]), with and without the addition of the nitric oxide (NO) synthase inhibitor L-NMMA. Plasma endothelin, plasma and urinary nitrates and nitrites, and cyclic GMP are measured at baseline and at the end of treatment. Irbesartan promoted a significant increase in EDV (from 433±147% to 488±75%; P=0.027) and EIV (from 442±130% to 495±104%; P=0.041). L-NMMA-induced vasoconstriction was significantly enhanced after irbesartan treatment (relative decrease of FBF from 33.4±9.5% to 39.5±5.6%; P=0.001). Plasma concentrations of endothelin fell significantly after irbesartan treatment (from 5.78±1.86 to 4.16±1.52 pg/mL; P=0.001). We concluded that long-term irbesartan treatment enhances both endothelium-dependent and -independent vascular vasodilation capacity. In addition to this non-specific effect, irbesartan restores the vasoconstriction capacity of NO synthase inhibitors, suggesting a direct effect on tonic NO release, and decreases endothelin production. These actions may play an important role in the vascular protecting effects of irbesartan.

Effect of Intermittent Pneumatic Foot Compression on Popliteal Artery Haemodynamics

Purpose: the aim was to investigate the effect of intermittent pneumatic foot compression (IPCfoot) on popliteal artery haemodynamics in normal individuals and in patients with intermittent claudication due to peripheral vascular disease (PVD) (Fontaine stage II). Material and methods: popliteal artery volume flow [vFl], pulsatility index [PI], mean velocity [mV], peak systolic [PSV] and end diastolic velocity [EDV], in 25 limbs of 20 normal subjects and 40 limbs of 32 stable claudicants were obtained in the sitting position before, during and within 30 seconds after the application of IPCfoot(applied pressure: 120 mmHg; inflation time: 3 seconds; deflation time: 17 seconds) using colour-flow duplex imaging (CFDI). The reproducibility of flow velocity estimations using CFDI in the horizontal [hor] (recovery) and sitting [sit] positions was evaluated in 20 limbs of normal controls and 20 limbs of claudicants. Results: popliteal artery vFl, mV, PSV and PI measurements were performed with a coefficient of variation (CV) of less than 14.6% among claudicants and of less than 13.3% in normal subjects. EDV is the least reproducible parameter with an overall CV range of 10.2–21.5% in normal controls and 9.1–18.6% in arteriopaths. On application of IPCfootpopliteal artery vFl increased by 111% in the control group (p<0.001) and by 51% in the claudicants (p<0.001). Within 30 seconds of the cessation of pump action flow decreased significantly in both groups (p<0.001), but maintained a significantly higher level than that at baseline (p<0.001, in both groups). The mV, PSV and EDV showed a similar pattern of significant changes. Both in normals and claudicants, the PI decreased with IPCfoot(p<0.001) and increased post-compression; however, it was significantly lower than baseline (p<0.005) within 30 seconds of impulse delivery. Conclusions: current CFDI technology enables a reproducible estimation of popliteal artery flow velocities. IPCfootcan significantly augment arterial calf inflow on an acute basis both in normals and claudicants. The increase of EDV and decrease of PI indicate that attenuation of peripheral resistance to flow is the main mechanism underlying the popliteal artery vFl enhancement on application of IPCfoot. Prospective trials on the long-term effect of IPCfootin the management of patients with PVD are indicated from the results of this study.

Effects of endurance exercise training on left ventricular systolic performance and ventriculoarterial coupling in patients with coronary artery disease

Background Endurance exercise training can increase left ventricular (LV) ejection fraction during dynamic exercise in coronary artery disease. This adaptation may be mediated by altered cardiac loading conditions rather than an improvement in intrinsic LV systolic function. To minimize these confounding effects, we used isometric handgrip exercise to assess the training-induced changes in LV systolic function and ventriculoarterial coupling. Methods Twenty-six patients (52 ± 2 years of age) trained for 12 months. LV function was assessed with radionuclide ventriculograpy. Results LV systolic reserve (the change in LV ejection fraction from rest to handgrip exercise) increased from –7.32 ± 1.2 to –3.4 ± 1.1 ( P = .033) without acute changes in end-diastolic volume or the effective arterial load. LV end-systolic elastance increased 37% ( P = .039) during handgrip exercise. Resting end-diastolic volume increased and the effective arterial load decreased after training. Conclusions Data suggest that in coronary artery disease adaptations to exercise training include a lower effective arterial load and an increase in EDV at rest, with an improvement in LV systolic function detectable only during afterload stress. (Am Heart J 1999;138:169-74.)

Early regression of left ventricular diastolic abnormalities in hypertensive patients treated with nifedipine

The effects of nifedipine on blood pressure (BP), left ventricular hypertrophy, and diastolic function were evaluated in 14 patients with essential hypertension (EH). All males with a mean age of 44 +/- 6 years (range 35-58 years), and in ten normotensive subjects (control group) aged 32-42 years (mean age 36 +/- 4). A complete echocardiogram (ECHO) was performed in basal conditions after 1 and 6 months of therapy with nifedipine (20-40 mg/day). Left ventricular echocardiograms (LV ECHO, M-mode, two-dimensional guided) were plotted with a simultaneous ECG tracing by means of a computerized system that allows evaluation of the following parameters: LV end-diastolic and systolic diameters (EDD, ESD); variations in LV diameter and volume during the entire cardiac cycle, and the velocities of such variations; end-diastolic thicknesses of the interventricular septum and posterior wall (ST, PWT); LV mass, mass/volume (M/V) index, end-diastolic diameter/thickness (D/Th) index, and LV ejection fraction (EF). Left ventricular volume curves were obtained and the contributions of rapid filling (RF) and atrial systole (AS) to EDV were evaluated. Filling velocities during RF (vRF) and AS (vAS) were estimated, as well as the isovolumic relaxation period (IR). No significant changes were observed in the heart rate. After 1 month of therapy, systolic and diastolic BP were significantly decreased (p less than 0.05). ST and PWT were reduced, with a simultaneous increase in EDD and EDV (p less than 0.01). LV mass was slightly reduced, as was the M/V index. The D/Th index was increased (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Echoventriculography -- a simultaneous analysis of two-dimensional echocardiography and cineventriculography.

Two-dimensional echocardiography underestimates left ventricular volume compared with cineventriculography. To exclude the influence of difference in heart rate, blood pressure, respiration phases and any effect of the contrast material on left ventricular function, simultaneous studies of two-dimensional echocardiography and cineventriculography-echoventriculography were performed in 46 patients. Apical two-dimensional echocardiograms in the right anterior oblique (RAO) equivalent view were recorded before and during cineventriculography in the 30 degrees RAO projection. End-diastolic and end-systolic volumes (EDV and ESV) were calculated using a disc method with a semiautomatic computer system. The echo transducer position relative to the left ventricular apex and long axis was analyzed. For EDV determined by two-dimensional echocardiography and cineventriculography, the linear regression equation was y = 0.659x + 0.8, SEE = +/- 26.2 ml, r = 0.907. For ESV, the regression equation was y = 0.571x + 17.8, r = 0.938, SEE = +/- 18.6 ml, and for ejection fraction (EF) it was y = 0.606x + 13.0, r = 0.803, SEE = +/- 9.1%. Injection of contrast material resulted in only a small increase of stroke volume, caused by an increase of EDV as analyzed by echoventriculography. In all but two patients, the transducer position was found to be anterior and superior to the left ventricular anatomic apex, as evaluated by filming the echo transducer position during cineventriculography in 46 patients in the 30 degrees RAO projection and in 15 patients consecutively in the 60 degrees left anterior oblique and 30-40 degrees cranial projections. Thus, tangential cuts of the ventricle resulted in underestimation of diameters, long axis and ventricular volumes. These methodologic problems are exacerbated by slice-thickness artifacts. Furthermore, different outlining of left ventricular contour -- outer border of ventricular trabeculae for cine ventriculography and inner border for two-dimensional echocardiography -- seemed to result in underestimation of volume by echocardiography.

Evaluation of the left ventricular function in aortic regurgitation by echocardiography and indicator dilution method.

The left ventricular function and severity of LV volume overload were assessed in 30 patients with aortic regurgitation by a combined use of echocardiography and indicator dilution method. With decreasing functional capacity of patients, there tended to be greater increase in EDV, and decreases in CO, EF, Vcf, and BAP(DN)/ESV, and shift of LV function curve downward and to the right, reflecting LV myocardial dysfunction. There was a substantial correlation between functional capacity and the severity of regurgitation as well as LV myocardial function, suggesting the possibility that clinical symptoms may depend upon both the myocardial function and severity of aortic regurgitation. In contrast with many patients with AR of functional class I or II, who had relatively normal LV function, the patients of class III consistently showed substantial LV myocardial dysfunction. After sublingual administration of ISDN, BAP lowered, EDV and RF decreased. Lowering of BAP and RF were more prominent in class III than in class I. It has been proved that a combined use of echocardiography and indicator dilution method is of value in assessing the left ventricular function and regurgitant fraction in patients with aortic regurgitation, allowing a better understanding of the disease process and the potential for recognizing patients who may require early valve replacement.

Ejection pressure and the diastolic left ventricular pressure-volume relation.

The influence of ejection pressure (EP) on the left ventricular end-diastolic pressure-volume (P-V) relation was examined in 24 paced, isolated canine hearts. A pressure servo system was used to control EP and monitor ventricular volume. For any given contractile state EP was varied: a) by 10- to 20-mmHg increments and the steady-state P-V response observed at each EP level (method A); or b) by instantaneously attaining the isovolumic condition (PO) from a given EDV and examining the immediate P-V response (method B). With either method it was possible to alter the P-V relation; the maximum variation occurred when, for a given EDV or EDP, EP was raised from a value less than 50% of its corresponding peak isovolumic pressure to PO. For the EDP range 2-25 mmHg, the direction and total magnitude of change were: 1) an increase in EDV 1.3-9 ml was required to maintain EDP constant; and 2) for a constant EDV, EDP decreased an average 16.5%+/-1.2 SE (6-23.9%; P less than .02). The EDP decline observed with method B was immediate and reversible within several beats upon returning to the ejecting mode. Thus, under the conditions of this experiment the diastolic pressure-volume relation is a physiological variable dependent on ejection pressure.

Quantitative angiocardioraphy in ischemic heart disease. The spectrum of abnormal left ventricular function and the role of abnormally contracting segments.

Appropriate surgical and medical management of the patient with ischemic heart disease depends upon a thorough assessment of the clinical and pathophysiologic derangements in left ventricular function. This study examined the spectrum of abnormalities in ventricular function found in 66 patients with documented coronary artery lesions. Catheterization and biplane angiocardiography were used to measure end-diastolic and end-systolic volume (EDV, ESV), systolic ejection fraction (SEF), ventricular mass (LVM), end-diastolic pressure (LVEDP), peak systolic and end-diastolic stress (PSS, EDS), and stroke work (SW). The pattern of ventricular contraction was assessed for hypokinesis, akinesis, and dyskinesis and graded according to severity. The SEF, SW, and contractile pattern were sensitive and interrelated indicators of left ventricular contractile dysfunction or fiber shortening. Measurements of ventricular filling or fiber lengthening (EDV, LVEDP, EDS) were related but less sensitive parameters of dysfunction. However, when contractile function was reduced to about one half of normal, there was an associated marked increase in EDV, EDS, and LVEDP. A wide spectrum of derangements was found ranging from virtually normal function in 18 patients with angina alone to severe dysfunction in 18 patients with myocardial infarction, mitral regurgitation, or heart failure. Abnormalities in ventricular function were uniformly associated with myocardial infarction. Angina alone was associated with minimal or no ventricular dysfunction. Most patients with mitral regurgitation and all patients with heart failure had severe ventricular dysfunction manifested by an increase in EDV, LVM, and PSS, a marked decrease in SEF and SW, and a severe abnormality in contractile pattern.

1. Hemodynanlic Aspect of Left Ventricular Failurei

A total of 52 cases including 4 normal subject and 48 patients with various heart diseases with or without failure were studied in resting state and under the acute effects of drugs with right and trans-septal left heart catheterization, and radioisotope indicator-dilution method. In this study, special attention was directed to the analysis of myocardial mechanics regulating the left ventricular performance and the following conclusions were obtained : 1) Patients with moderate or severe failure showed a decrease in cardiac index, stroke index, left ventricular fraction ejected per beat, MCSR, MSER and an increase in EDV, where-as patients without failure or those with mild failure had normal or increased cardiac index and stroke volume. 2) Measurements of EDP and EDV in association with the calculation of CSR, T and F as shown in our study proved to be useful in the analysis of the effects of drugs on inotropism, chronotropism or afterload of the left ventricle.