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PubMed1982

A method to estimate cardiac volume by two-dimensional echocardiograms recorded from one extracorporeal point.

This paper presents a method for estimating the volume of a cardiac region from its oblique sectional images recorded with a sector scanner. The probe of the scanner is attached to the chest wall and an ultrasonic beam is cast from a fixed intercostal space. In a previous paper a method of calculation for the above recording technique was reported. The present method is superior to the previous one because it minimizes calculation error and is applicable to organs of intricate shape.

Cardiac Volume↗
PubMed1991

Atrial natriuretic factor, cardiac volumes and filling pressures during exercise in congestive heart failure.

To study the mechanism of atrial natriuretic factor (ANF) release in heart failure, we measured plasma ANF concentrations, cardiac volumes and filling pressures at rest and during three graded exercise levels (E1, E2, E3) in six male patients with congestive heart failure (CHF) and compared them with 13 normal male subjects. At rest, ANF concentrations were sixfold higher in patients with CHF than in normal subjects (at rest: 53 +/- 12 vs 8 +/- 1 pmol.l-1; P less than 0.02). End-systolic ventricular volumes were increased threefold in patients with CHF (P less than 0.02) despite normal mean central venous pressure, pulmonary artery pressure (PAP) and pulmonary wedge pressure (PWP). A positive correlation was found between end-systolic ventricular volumes and plasma ANF (r = 0.93, P less than 0.001). During exercise, ANF rose by 120% over basal values both in patients with CHF and in normal subjects (P less than 0.01). Volumes higher than normal in patients with CHF increased further at E2 (P less than 0.05) in contrast to a decrease of systolic volumes recorded in normal subjects (P less than 0.05). Filling pressures rising abnormally in patients with CHF correlated with plasma ANF during exercise (r = 0.53, P less than 0.02 for PAP; r = 0.51, P less than 0.05 for PWP). In conclusion, our data suggest that ANF release in CHF is regulated at rest by cardiac volumes when filling pressures are still normal. During exercise, ANF release is not impaired in CHF with normal rest filling pressures and is regulated during exercise by left filling pressures.

Aged↗
PubMed1997

Myocardial angiotensin receptor type 1 gene expression in a rat model of cardiac volume overload.

To investigate the regulation of the angiotensin receptor type 1 (AT1) in different organs in cardiac volume overload, we measured AT1 mRNA content in the atria, left and right ventricle, kidney and liver of rats with an aortocaval shunt, produced by infrarenal aortocaval puncture 4 weeks earlier. For angiotensin receptor mRNA quantitation a novel quantitative PCR procedure based on liquid phase hybridization was used that allowed the determination of absolute AT1 mRNA copy numbers and its comparison in different organs. Glyceraldehydephosphate dehydrogenase (GAPDH) mRNA was measured by RT-PCR to control externally equal mRNA content and quality of RNA extraction in shunt animals and controls. Heart weight was increased in the shunt animals, with the greatest increase in the atria. Blood pressure, plasma renin activity, plasma angiotensin I and II and aldosterone concentrations were not significantly altered. The AT1 mRNA content was significantly increased in the atria (shunt: 1167 +/- 350 copies AT1 mRNA/ng RNA vs controls: 803 +/- 240; p < 0.05). No change was found in the right or left ventricle, in the kidney and liver. The findings document that atrial hypertrophy in cardiac volume overload parallel with a significant increase in atrial AT1 mRNA content.

Animals↗
PubMed1990

Reduced supine cardiac volumes and diastolic filling rates in elderly patients with chronic medical conditions. Implications for postural blood pressure homeostasis.

Very elderly individuals with multiple chronic illnesses are at high risk of orthostatic hypotension, falls, and associated morbidity and mortality. Alterations in cardiac volumes and filling characteristics may contribute in part to an increased prevalence of orthostatic hypotension and falls in these people. In this study cardiac function was evaluated with gated radionuclide ventriculography in eight healthy young subjects (19-38 years) and 25 elderly persons with stable chronic illnesses (73-96 years), 14 of whom had a history of recurrent falls. Blood pressure was measured supine during the radionuclide ventriculography, then after one minute of standing. Supine stroke volume index, end diastolic volume index, cardiac index, and peak filling rates were significantly lower in elderly subjects compared to young, and ejection fraction and end systolic volume index (measures of systolic function) were the same in young and old. Compared to the young, elderly subjects had a reduction in ventricular filling during the first third of diastole, but an augmentation in the last third, during atrial contraction. Within the group of elderly subjects, the directional change in systolic blood pressure during orthostasis was significantly correlated with basal supine systolic blood pressure (R = 0.81, P less than .0001) and supine cardiac index (R = 0.66, P = .002). Thus, very old people representative of those seen in clinical practice have reduced cardiac volumes and impaired early diastolic filling, a result possibly related to elevations in systolic blood pressure. These changes in cardiac structure and function may contribute, in part, to orthostatic hypotension in advanced age.

Accidental Falls↗
PubMed1993

Reproducibility of cardiac volume measurements including left ventricular mass determined by MRI.

Cardiac volumes including left ventricular mass were determined by magnetic resonance imaging (MRI) in 30 patients using a contiguous multislice technique. Eleven patients were studied on two different days. Intra- as well as interobserver and interstudy variation were evaluated. For volume measurements the standard deviation of differences (SDD) was rather constant, independent of the size of the measured volume indicating lower percentual variability in measuring large volumes. Lowest variability was noticed for left ventricular myocardial mass estimates between observers as well as between studies. In 13 patients left ventricular mass was estimated by this technique as well as by a method using only one long axis and four short axis slices and by two-dimensional echocardiography. Although highly correlated, limits of agreement between the methods were too wide to accept interchangeable clinical use of the methods.

Adult↗
PubMed1993

Effect of perindopril in rat cardiac volume overload.

The aortocaval fistula is a classic model of pure cardiac volume overload in rats. This model is characterized by dilation of the ventricular cavities and eccentric cardiac hypertrophy. There are also changes in peripheral arterial flow: high flow in the proximal part of the aorta, upstream of the shunt, and low flow in the distal aorta, downstream of the shunt. The chronic effects of converting enzyme inhibition in this model of volume overload have not yet been measured. We tested the effect of blood pressure and flow on cardiac mass and aortic dilatory pathway in normotensive Wistar and spontaneously hypertensive rats (SHR) with an aortocaval fistula. One half of the sham-operated rats and the normotensive and hypertensive rats with aortocaval fistulas were treated for 1 month with perindopril (2 mg/kg by daily gavage). Urine and plasma were collected at death, the heart was weighed, and the proximal (thoracic) and distal (abdominal) aortas were quickly removed and frozen in liquid nitrogen for measurement of cyclic guanosine monophosphate (cGMP). Blood pressure was always higher in SHR than in Wistar rats, in sham-operated rats than in those with aortocaval fistulas, and in untreated than in perindopril-treated rats. Similarly, the heart weight/body weight ratio was higher in SHR than in Wistar rats, in those with aortocaval fistulas than in sham-operated rats, and in untreated than in Wistar rats, in those with aortocaval fistulas than in sham-operated rats, and in untreated than in perindopril-treated rats. The aortocaval fistula increased the plasma atrial natriuretic factor and perindopril reduced it.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2000

Effects of continuous positive airway pressure on cardiac volumes in patients with ischemic and dilated cardiomyopathy.

The effects of continuous positive airway pressure (CPAP) on left (LV) and right ventricular (RV) volumes in patients with congestive heart failure (CHF) have not been studied. We hypothesized that CPAP would cause greater reductions in cardiac volumes in CHF patients with idiopathic dilated cardiomyopathy (IDC) than in those with ischemic cardiomyopathy (IsC), because their ventricles are more compliant. The effects of a 30-min CPAP application at 10 cm H(2)O on RV and LV end-diastolic (EDV) and end-systolic volumes (ESV), determined by radionuclide angiography, were therefore tested in 22 patients with CHF due to IsC (n = 13) or IDC (n = 9). CPAP-induced reductions in LVEDV, LVESV, RVEDV, and RVESV were significantly greater (p < 0.05) in the IDC than in the IsC group. Whereas in the IsC group CPAP caused no significant changes in LV or RV volumes, in the IDC group it induced significant reductions in RVEDV (527 +/- 77 ml to 354 +/- 50 ml, p = 0.03) and RVESV (400 +/- 78 ml to 272 +/- 54 ml, p = 0.04) that were greater than any reductions in LVEDV and LVESV. We conclude that CPAP causes greater short-term reductions in RV and LV volumes in CHF patients with IDC than in those with IsC, and that among patients with IDC, CPAP causes greater reductions in RV than in LV volumes.

Aged↗
PubMed2006

[Mid-term results of overlapping cardiac volume reduction for ischemic cardiomyopathy].

BACKGROUND: Left ventricular restoration (LVR) is thought to be effective for ischemic cardiomyopathy (ICM). We assessed the early and mid-term results of overlapping cardiac volume reduction (OLCVR) as an operation for LVR on patients with ICM. METHODS: From February to June 2004, 4 patients with ICM underwent OLCVR in our department. RESULTS: There was no death. Significant decreases in the left ventricular end diastolic volume index and in the left ventricular end systolic volume index were observed in the early postoperative period in all the 4 patients. These effects were still evident 1 year later, with improved New York Heart Association (NYHA) functional class and a smaller left ventricular diastolic diameter. One patient required implantation of a cardioverter defibrillator 16 months postoperatively. CONCLUSION: The favorable early and mid-term results of the OLCVR indicate that it is an effective procedure for patients with ICM.

Aged↗
PubMed2003

Effects of photon attenuation on the determination of cardiac volumes from reconstructed counts in gated blood pool SPET.

In gated cardiac blood pool single-photon emission tomography (SPET), the volume of a ventricle may be determined by a method that exploits the proportionality between that volume and the total reconstructed counts within a larger volume of interest that includes the actual ventricle. The present work was carried out to determine how the attenuation of photons modifies the reconstructed counts obtained with this technique, and how this affects the accuracy of volume determination. Furthermore, we wanted to investigate how count-based determination of ventricle volumes is affected by the total SPET rotation angle and by different arm positions. We used micro -maps derived from computed tomography (CT) series of nine arbitrarily chosen patients to calculate a volume correction factor for each cardiac volume manually drawn on the CT images. An anthropomorphic chest phantom was used to confirm the calculation of correction factors. For the regions of the ventricles contained within a CT slice through the central part of the heart, the left to right volume ratio needed to be corrected by factors of 1.21 and 1.12 for 180 degrees and 360 degrees rotation, respectively. When all voxels within the left and right ventricles were included, the required volume ratio correction factor was close to 1. However, the variation among patients was larger for a 180 degrees (range 0.97-1.08) than for a 360 degrees rotation arc (range 1.0-1.03).

Adult↗
PubMed2004

High-resolution transthoracic real-time three-dimensional echocardiography: quantitation of cardiac volumes and function using semi-automatic border detection and comparison with cardiac magnetic resonance imaging.

OBJECTIVES: We sought to validate high-resolution transthoracic real-time (RT) three-dimensional echocardiography (3DE), in combination with a novel semi-automatic contour detection algorithm, for the assessment of left ventricular (LV) volumes and function in patients. BACKGROUND: Quantitative RT-3DE has been limited by impaired image quality and time-consuming manual data analysis. METHODS: Twenty-four subjects with abnormal (n = 14) or normal (n = 10) LVs were investigated. The results for end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF) obtained by manual tracing were compared with the results determined by the semi-automatic border detection algorithm. Moreover, the results of the semi-automatic method were compared with volumes and EF obtained by cardiac magnetic resonance imaging (CMRI). RESULTS: Excellent correlation coefficients (r = 0.98 to 0.99) and low variability (EDV -1.3 +/- 8.6 ml; ESV -0.2 +/- 5.4 ml; EF -0.1 +/- 2.7%; p = NS) were observed between the semi-automatically and manually assessed data. The RT-3DE data correlated highly with CMRI (r = 0.98). However, LV volumes were underestimated by RT-3DE compared with CMRI (EDV -13.6 +/- 18.9 ml, p = 0.002; ESV -12.8 +/- 20.5 ml, p = 0.005). The difference for EF was not significant between the two methods (EF 0.9 +/- 4.4%, p = NS). Observer variability was acceptable, and repeatability of the method was excellent. CONCLUSIONS: The RT-3DE, in combination with a semi-automatic contour tracing algorithm, allows accurate determination of cardiac volumes and function compared with both manual tracing and CMRI. High repeatability suggests applicability of the method for the serial follow-up of patients with cardiac disease.

Aged↗
PubMed1992

Radionuclide cardiac volumes: effects of region of interest selection and correction for Compton scatter using a buildup factor.

The effects of region of interest (ROI) selection and correction for Compton-scattered photons using a buildup factor on radionuclide left ventricular volumes calculated by the Links method were compared in 19 humans with contrast ventriculography and in phantoms. Three different methods of ROI selection were compared: a manual ROI, a second derivative ROI and a 50% count-threshold ROI. In phantoms without Compton scatter correction, volumes were overestimated by 30% (manual ROI), 20% (derivative ROI) and 1% (count threshold ROI). In subjects, results without Compton scatter correction were similar with overestimates of 50% (manual ROI) and 20% (derivative ROI) and an underestimate by 3% (count threshold method). Correction for Compton-scattered photons with the use of a phantom-derived buildup factor resulted in improved accuracy for the manual ROI (+15%) and the derivative ROI (0%). A 50% count threshold ROI following interpolative background subtraction allows the accurate calculation of cardiac volumes without the need for scatter correction, while a second derivative ROI method requires a correction for Compton scatter with the use of a buildup factor.

Cardiac Volume↗
PubMed1995

Rapid activation of the type B versus type A natriuretic factor gene by aortocaval shunt induced cardiac volume overload.

OBJECTIVE: The aim was to compare activities of the type A and type B natriuretic factor genes during development of cardiac hypertrophy by use of a non-radioactive method designed for assessment of stable atrial and brain natriuretic factor (ANF, BNF) transcript levels in biopsy sized tissue samples. METHODS: At 1 and 7 days after aortocaval shunt or sham surgery in rats, quantitative reverse transcriptase mediated polymerase chain reaction (Q-RT-PCR) was used to determine mRNA levels in cardiac tissues. Phosphoglycerate kinase-1 (PGK-1) mRNA levels served as an external standard for Q-RT-CR. RESULTS: The shunt increased left ventricular end diastolic pressure at days 1 and 7, and cardiac weight was increased by day 7. By day 1, left ventricular BNF mRNA levels were twice those of controls, whereas ANF mRNA levels were not changed. By day 7, left ventricular BNF mRNA levels were increased 15-fold, and those for ANF were increased fivefold; the BNF mRNAs were also increased in right atria and right ventricle, about fivefold in both cases. CONCLUSIONS: Both natriuretic factor genes were activated by cardiac volume overload, and the increase in the level of left ventricular BNF transcripts-observed for the first time-was in fact more rapid and exceeded that of ANF. The Q-RT-PCR assay will be of value to investigate the response to increased work load of cardiac muscle in vivo.

Animals↗
PubMed1991

Effects of posture, Valsalva maneuver and respiration on atrial flutter rate: an effect mediated through cardiac volume.

The effects of passive upright tilting from 0 degrees to +60 degrees (n = 27), Valsalva maneuver (n = 16) and respiration (n = 10) on the rate of atrial flutter were studied in 27 patients. After tilting to +60 degrees, the atrial flutter cycle length shortened in all patients from 247.5 +/- 7 to 236.7 +/- 6.9 ms (range of shortening 1 to 21 ms, p less than 0.001). The Valsalva maneuver (strain of 40 mm Hg) shortened the flutter cycle length during the strain (phase 2) from 242.2 +/- 4.6 to 230.5 +/- 5 ms (range of shortening 2 to 19 ms, p less than 0.001). In 10 patients whose respiration was monitored, the flutter cycle length consistently prolonged during inspiration and shortened during expiration. Combined beta-adrenergic and muscarinic receptor blockade in six patients did not significantly alter the flutter cycle length at rest or the effects of the various maneuvers on the changes in flutter cycle length. This study revealed that the atrial flutter cycle length can be shortened by passive upright tilting, the strain phase of the Valsalva maneuver and expiration. Changes in flutter cycle length were independent of autonomic tone, implying that by decreasing cardiac volume, these maneuvers affect characteristics of the atrial flutter circuit, thereby producing dynamic changes in the rate of atrial flutter.

Atrial Flutter↗
PubMedDate not supplied

Effect of patient imaging angle on apparent cardiac volumes and the potential impact on measurement of valvular regurgitant fractions.

The accurate measurement of cardiac chamber volume is of major importance in assessing cardiac performance. Accurate equilibrium radionuclide volume estimations are difficult to obtain, due to the geometry of the chambers, and the physical characteristics of the imaging system. The purpose of this study was to examine the effects of imaging projections on relative cardiac chamber volumes, indexes, and stroke volume ratios. Twenty-two male patients, free of clinical evidence of disease, were studied. A series of four 2-minute acquisitions were made with the patient successively imaged in the anterior, 30 degrees left anterior oblique (LAO), 45 degrees LAO, and 60 degrees LAO projections with 15 degrees of caudal inclination. Filtered stroke volume and original images were used by the operator to assign right ventricular (RV), left ventricular (LV), and a combined right and left ventricular (TOT) regions-of-interest. From the data we determined end-diastolic counts (EDC), end-systolic counts (ESC), stroke counts (SC), ejection fractions (EF), and R/L stroke count ratios. The following changes were observed as the projection was moved from the anterior to 60 degrees LAO: 1) all RV parameters decreased in value, including, RVEDC (P less than .001), RVESC (P less than .01), RVESC (P less than .01) and RVEF (P less than .001); 2) LVEDC and LVESC (both P less than .01) increased while LVEF decreased (P less than .004); and 3) the R/L stroke count ratio decreased (P less than .001). Variability could be explained by 1) chamber overlap and geometry; 2) patient variability; and 3) intrachamber, interchamber and chest wall photon attenuation and scatter. We suggest that close attention to detail, with computer assistance, to optimally position the patient may reduce the effect of inherent limitations in radionuclide volumetric measurements, thus improving the reliability and usefulness of existing studies.

Aged↗
PubMed1975

[Usability of methods for the determination of minute cardiac volume under clinical conditions].

Methods for determination of cardiac output are described and their evaluation and possibilities to use them in clinical practice mentioned. Out of the invasive methods apart from the classical Fick's method, the dye dilution method is of advantage during catheterization, being relatively simple and ready to be easily repeated if necessary directly at the bed side. The common disadvantage of all invasive methods is the disturbance of the patient's basal state. Noninvasive methods yield results suitable more or less for orientation only. From these techniques the indirect method of Fick using the rebreathing of CO2 is simple and can be applied at the bed side. So called physical methods are already obsolete at present.

Cardiac Catheterization↗