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PubMedDate not supplied

[Value of isotopic methods in the diagnosis of myocardial infarction of the right ventricle].

In the left ventricle, isotope techniques can be used to study the perfusion of the myocardium or the ventricular function. Because of the thinness of the walls of the right heart, the classical examinations and Thallium 201 perfusion cannot be used to demonstrate a disorder of perfusion in the right ventricle. Nevertheless, it is possible, with the aid of Technetium 99m labeled pyrophosphate, to diagnose and localise necrosis of the inferior wall with an acceptable degree of sensitivity, during the acute phase of the infarction. However, the major value of isotope techniques is to evaluate right ventricular function by determining the value of the global ejection fraction and the kinetic anomalies of the different walls. These methods, together with echocardiography, allow the diagnosis of lesions of the inferior part of the right ventricle in patients with inferior necrosis... Furthermore, because these methods allow quantification and because they are reproducible and repeatable, they can be used to follow the course of the right ventricular function in response to treatment.

Evaluation Studies as Topic↗

PubMed2003

[The arrhythmogenic right ventricular cardiomyopathy (ARVC)].

The following report illustrates the case of a 40-year old patient, who was transferred to our hospital because of a symptomatic sustained ventricular tachycardia (VT). The documented VT showed typical left bundle branch block morphology with an inferior axis, which was accompanied by repolarization abnormalities in the right precordial leads, as revealed by the surface ECG. While coronary angiography allowed the exclusion of an obstructive coronary heart disease and confirmed an intact left ventricular function, the right ventricular angiography as well as the MRI demonstrated not only reduced right ventricular function but also regional abnormalities of contraction in the inferior and diaphragmal regions and typical "outpouchings" and "bulgings". The MRI also provided evidence for sporadic fatty infiltrations of the right ventricle. In the electrophysiological study, sustained VT could be reproducibly induced, while showing the typical RVOT configuration, which corresponded to the clinically apparent VT. Since these examination results matched with the criteria of McKenna et al., arrhythmogenic right ventricular cardiomyopathy was diagnosed. The patient underwent implantation of a cardioverter-defibrillator (ICD) and medical treatment with metoprolol. This particular case report was selected because it shows a typical presentation of an ARVC. Furthermore, the present example offers the possibility of demonstrating that in the case of an ARVC in the regions of the right ventricle, arrhythmogenic areals can also be found which seem morphologically inconspicuous.

Adult↗

PubMed1998

Variability of repeated facial nerve electroneurography in healthy subjects.

BACKGROUND: Facial electroneurography is an objective measurement of a muscle compound action potential. The amplitude ratio between the paretic and the normal side is used as a basis for estimating the prognosis of facial palsy. According to Esslen, the difference of amplitudes in healthy subjects is only 3%. Twenty healthy test persons were investigated with the aim of 1. reproducing the published data on the left-right difference in normal test subjects and 2. determining whether the amplitude ratio is constant over time after repeated measurements. STUDY DESIGN: Bilateral electroneurography was conducted on 20 healthy volunteers (age range, 23-36 y; 12 men, eight women). Two investigators performed four measurements at 1-week intervals on every subject. RESULTS: Mean amplitude ratio was 32.5%. Repeated measurements on the same individual differed considerably-- from 0% to 80%. The 99% confidence interval computed from the data ranged from 26% to 39% amplitude ratio. CONCLUSION: The symmetry of facial evoked compound potentials postulated by Esslen and Fisch is not supported by these data. As have other investigators, the authors found significant left-right differences in healthy subjects. Furthermore, they showed for the first time that the amplitude ratio is not constant in every individual at repeated measurements. In light of these data, prognosis of facial palsy based on electroneurographic data alone seems doubtful.

Adult↗

PubMed1993

[Monitoring of right ventricular ejection fraction with a modified pulmonary artery catheter].

The thermodilution method for measuring right ventricular ejection fraction (RVEFTD) is described. The reproducibility of RVEFTD measurements was determined in 48 critically ill patients who all needed pharmacological inotropic support and mechanical ventilation. A coefficient of variance of 12.6% on RVEFTD determinations was found. In 46 of 48 patients (96%), the catheter did not need repositioning.

Cardiac Catheterization↗

PubMed1977

Studies on methods for determination of the distribution of cardiac output in the mouse.

Different techniques for determining cardiac output distribution in the mouse have been studied. The soluble indicator technique using injection of rubidium on the right side of the heart was found to give a satisfactory reproducibility which made it possible to determine cardiac output fractions in the normal mouse. The use of radioactivity-labelled microspheres, which must be injected on the side of the heart, was found to give unreliable and non-reproducible results. This was due to difficulty in depositing the microspheres into the left ventricle both when a catheter was inserted via the right carotid artery, or by means of cardiac puncture.

Animals↗

PubMed2004

The use of isovolumic contraction velocity to determine right ventricular state of contractility and filling pressures A pulsed Doppler tissue imaging study.

AIMS: Echocardiographic techniques have not so far been able to provide a good estimation of myocardial contractility in humans. Myocardial motion during the isovolumic contraction phase, measured by Doppler tissue imaging, has only recently in experimental models been shown to describe myocardial contractility. The aim of the present clinical study was to investigate the relationship between right ventricular isovolumic contraction velocity and right ventricular state of contractility. METHODS AND RESULTS: Doppler tissue imaging and cardiac catheterization were performed simultaneously in 26 consecutive patients with different cardiac diseases (18 males, mean age 52 +/- 12, range 23-75 years). Peak isovolumic contraction velocity was measured using Doppler tissue imaging at 2 levels of the right ventricular free wall. During cardiac catheterization, the first derivative of right ventricular pressure related to the pulmonary artery peak pressure (dP/dt/P(max)) was measured. Furthermore, right ventricular end diastolic pressure, right atrial mean pressure, pulmonary artery systolic pressure, and pulmonary artery resistance, were also measured. A significant relationship was found between isovolumic contraction velocity and dP/dt/P(max) (r = 0.59, p < 0.01). This relationship was strengthened after excluding patients with elevated right atrial pressures (r = 0.77, p < 0.001). Furthermore, a correlation was also found between basal and mid cavity isovolumic contraction velocity and right ventricular end diastolic pressure (r = -0.47, r = -0.49, p < 0.05) as well as right atrial mean pressure (r = -0.63, r = -0.55, p < 0.01). CONCLUSION: Isovolumic contraction velocity is a reproducible and easily obtainable non-invasive parameter which correlates with invasive measurements of right ventricular state of contractility and right ventricular filling pressures.

Adult↗

PubMed1993

Right heart pressure determination by Doppler in infants with tricuspid regurgitation.

Doppler and direct measurements of right ventricle to right atrial pressure drop were made during cardiac catheterisation on 28 occasions in 26 infants with congenital heart disease. Age was 10 days to 12 months (median 4.5 months), and weight was 3.1 to 9.0 kg (median 4.7 kg). We measured peak velocity of tricuspid regurgitation by continuous wave Doppler, and the pressure drop was calculated using the modified Bernoulli equation (delta p = 4v2). There was a high correlation (r = 0.95) between direct and Doppler measurements. Doppler values tended to underestimate the right ventricle to right atrial pressure drop, but this was not of clinical significance (mean 2 mm Hg). The 95% confidence interval for the Doppler velocity was -0.41 to +0.26 m/sec, and was consistent across the range of pressures studied. Variability between observers was tested, by two observers performing sequential paired examinations on 16 newborn babies with tricuspid regurgitation. The coefficient of repeatability was 6.3 mm Hg (95% confidence interval 4.7 to 9.5 mm Hg) or 0.26 m/sec (0.18 to 0.50 m/sec). This method of right ventricular pressure estimation, validated previously only in older children and adults, is a reproducible and accurate technique in infants with tricuspid regurgitation.

Blood Pressure↗

PubMed2001

Transient but marked ST elevation in precordial leads caused by ischemia of the isolated right ventricular branch.

The present case is a 64 year-old man in whom transient but marked ST elevation was confirmed in the contralateral precordial leads (V1-3) during percutaneous transluminal coronary angioplasty (PTCA) of the proximal right coronary artery, suggesting that the patient had anteroseptal ischemia. The ST elevation persisted even after the balloon was deflated, and no changes in the left coronary artery were detected. In addition, blood flow in the affected area of the right coronary artery was favorable and there was a transient delay only in the right ventricular branch. Once blood flow in the right ventricular branch improved, ST returned to baseline, and when the right ventricular branch was again occluded by the balloon, ST elevation occurred in a reproducible manner. Hence, the electrocardiographic changes in the precordial leads were caused by occlusion of the right ventricular branch. It is rare to observe ST elevation caused by isolated right ventricular branch ischemia.

Angioplasty, Balloon, Coronary↗

PubMed2006

Interbreath-hold reproducibility of lung tumour position and reduction of the internal target volume using a voluntary breath-hold method with spirometer during stereotactic radiotherapy for lung tumours.

The purpose of this study was to evaluate the interbreath-hold reproducibility of the tumour (gross tumour volume, GTV) position and relative reduction of the internal target volume (ITV) using a voluntary breath-hold method with a spirometer in a clinical setting of stereotactic radiotherapy (SRT) for lung tumours 11 patients with 14 lung tumours were enrolled in this study. CT scans were performed once at the free breathing phase and five times at the breath holding phase before the first treatment day. Patients held their breath at the end-expiration phase under spirometer-based monitoring. All GTVs were delineated by a physician and the GTV centroid was calculated automatically. To evaluate the interbreath-hold reproducibility of the tumour position, we measured the distance of three dimensions (craniocaudal, CC; left-right, LR; anteroposterior, AP) and vectors between the GTV centroid and bony landmark. The reproducibility was defined as the average of the differences between the GTV centroid and bony landmark from the second to fifth CT scans with regard to that from the first CT scans. We also evaluated the relative reduction of ITV between the free breathing and breath-holding phase. The interbreath-hold reproducibility of the tumour position was 1.3+/-1.3 mm, 1.4+/-1.8 mm, 2.1+/-1.6 mm and 3.3+/-2.2 mm in CC, LR and AP directions and vectors, respectively. ITV at the breath-holding phase was significantly smaller than that at the free breathing phase (P<0.01). In conclusion, the voluntary breath-hold method with a spirometer is feasible, with relatively good reproducibility of the tumour position for SRT in the clinical setting.

Aged↗

PubMed2000

MR volumetric analysis of the human basal ganglia: normative data.

RATIONALE AND OBJECTIVES: The authors undertook this study to identify a precise, semiautomated, reproducible magnetic resonance (MR) imaging technique for measuring the basal ganglia, to establish normative volumetric data, and to verify the presence of previously reported asymmetries. MATERIALS AND METHODS: Twenty-eight healthy adults underwent cranial MR examination. The volumes of the various components of the basal ganglia were measured by means of a combination of thresholding and manual tracing techniques performed with specialized software. The validity of these measurements was assessed by fashioning, imaging, and measuring a practical basal ganglia phantom. Measurement accuracy was also established by means of inter- and intrarater reliability indexes. Normalized volumes were statistically analyzed with analysis of variance and paired t tests. RESULTS: The absolute values of the various components of the basal ganglia varied widely even though the volumes were normalized to differences in intracranial volume. The right caudate nucleus volume was significantly (P < .000001) larger than the left in both men and women and in both right-handed and non-right-handed subjects. This asymmetry led to an increase in the overall volume of the basal ganglia on the right. CONCLUSION: The authors have defined a precise, reproducible technique for measuring various components of the basal ganglia and have established normative data. The basal ganglia, similar to other brain structures, exhibit hemispheric lateralization.

Adult↗

PubMed1992

Ultrasonographic examination of the liver in sheep.

The purpose of the study reported here was to get detailed information about the normal size and texture of the liver in sheep by means of ultrasonographic examinations. Structure, location, and shape of the liver, gallbladder, portal vein, and caudal vena cava were examined ultrasonographically in 100 sheep. Furthermore, 10 sheep were scanned 10 times within 2 weeks to determine reproducibility of findings. Examinations were performed on the right side of the abdomen in the seventh through twelfth intercostal spaces. In each intercostal space, the dimensions of the liver, and, if visible, the location and diameter of the caudal vena cava and portal vein were determined. The angle of the liver, and location and size of the gallbladder also were determined. Ultrasonographic measurements of liver size and location in healthy sheep can be used as references for changes in liver size attributable to illness.

Animals↗

PubMed1993

Monophasic action potentials in a patient with multiform ventricular tachycardia without QT prolongation.

A 41 year old woman had multiform ventricular tachycardia without QT prolongation. Monophasic action potentials were recorded from the right ventricle during the attacks of multiform ventricular tachycardia and effective refractory periods were examined at the same sites. There was no abnormal hump to suggest early afterdepolarisation in the monophasic action potentials, but there was dispersion of the effective refractory period in the right ventricle (80 ms). Stimulation from the right ventricular apex, where the effective refractory period was shortest, reproducibly induced multiform ventricular tachycardia. Two weeks after admission, when her condition was stable, multiform ventricular tachycardia could not be induced and the dispersion of the effective refractory period in the right ventricle was 20 ms.

Action Potentials↗

PubMed1992

Quantification of left to right atrial shunts with velocity-encoded cine nuclear magnetic resonance imaging.

OBJECTIVES: The purpose of this study was to evaluate the ability of velocity-encoded nuclear magnetic resonance (NMR) imaging to quantify left to right intracardiac shunts in patients with an atrial septal defect. BACKGROUND: Quantification of intracardiac shunts is clinically important in planning therapy. METHODS: Velocity-encoded NMR imaging was used to quantify stroke flow in the aorta and in the main pulmonary artery in a group of patients who were known to have an increased pulmonary to systemic flow ratio (Qp/Qs). The velocity-encoded NMR flow data were used to calculate Qp/Qs, and these values were compared with measurements of Qp/Qs obtained with oximetric data derived from cardiac catheterization and from stroke volume measurements of the two ventricles by using volumetric data from biphasic spin echo and cine NMR images obtained at end-diastole and end-systole. RESULTS: Two independent observers measured Qp/Qs by using velocity-encoded NMR imaging in 11 patients and found Qp/Qs ranging from 1.4:1 to 3.9:1. These measurements correlated well with both oximetric data (r = 0.91, SEE = 0.35) and ventricular volumetric data (r = 0.94, SEE = 0.30). Interobserver reproducibility for Qp/Qs by velocity-encoded NMR imaging was good (r = 0.97, SEE = 0.20). CONCLUSIONS: Velocity-encoded NMR imaging is an accurate and reproducible method for measuring Qp/Qs in left to right shunts. Because it is completely noninvasive, it can be used to monitor shunt volume over time.

Adolescent↗

PubMedDate not supplied

Tricuspid annular motion.

Triscupid annular motion is related to right ventricular systolic function in the same way mitral annulus motion is related to left ventricular function. Tricuspid annular excursion reflects the longitudinal motion of the right ventricle, and the systolic descent of the anulus correlates with systolic venous inflow to the right atrium. However, it has not been shown clearly how to reproducibly quantify this motion. Therefore we describe a method to measure triscuspid annular motion using two-dimensional oriented M-mode echocardiography from the apical view. We studied a group of 10 normal subjects (mean age, 28.7 years; range, 25 to 38 years) and a group of 29 patients (mean age, 57.2 years; range, 20 to 84 years) with disease of the left side of the heart but no evidence of involvement of the right side of the heart. In each subject, tricuspid and mitral annular motion were measured respectively at their lateral, septal or medial, anterior, and posterior margin points. The total tricuspid annular motion for normal subjects was, as follows: lateral, 24.9 +/- 3.5 mm; medial, 20.1 +/- 2.5 mm; anterior, 21.6 +/- 3.8 mm; and posterior, 22.3 +/- 2.3 mm. Interobserver and intraobserver variability was low, with a coefficient of variance for the different annular points ranging from 6.19% to 11.56% between observers and from 4.10% to 7.26% within observer. We conclude that it is possible to measure tricuspid annular motion with this method in a reproducible way and to use it as a diagnostic tool in evaluating function of the right side of the heart.

Adult↗

PubMed1996

Condylar movement and centric relation in patients with internal derangement of the temporomandibular joint.

This study was designed to compare the reproducibility of the condylar translation pathway and the centric relation position in patients with and without internal derangement of the temporomandibular joint. Reproducibility of condylar movement and variability of the axis point of condylar rotation in centric relation was studied in 15 patients with internal derangement of the temporomandibular joint and 15 patients with no history or clinical signs of mandibular dysfunction. Condylar movement and axis point location were recorded with a sagittal recording device at three separate recording sessions. Lead markers were placed on the skin over the axis and orbital points, and lateral cephalometric radiographs were taken at each session. Analysis of cephalometric and axiographic recordings included both linear and angular measurements. Analysis of the condylar movement pathway revealed greater within-subject reproducibility in the control group for both the right and left condyles (p < 0.0005 and p < 0.0003, respectively). The axis point of condylar rotation in centric relation, as shown by cephalometric analysis, had significantly more within-subject variability in the horizontal plane for the control group (p < 0.003). There was no significant difference between groups for within-subject variability of condylar position in the vertical direction. These findings are consistent with the contemporary concept of centric relation that a vertically stable condyle with a disk interposed against the anterior eminence is capable of functional adaptation in the horizontal plane. The results have implications with regard to treatment and rehabilitation of patients with temporomandibular joint internal derangement.

Adaptation, Physiological↗

PubMed2005

Effects of antiarrhythmic drug therapy on atrioventricular nodal function during atrial fibrillation in humans.

AIMS: To assess the effects of metoprolol and amiodarone on atrial and ventricular activity during atrial fibrillation (AF) in post-surgical patients, and to develop and use a mathematical model of the atrioventricular (AV) node during AF that incorporates parameters describing the properties of the AV node to evaluate the physiological basis of the drug effects. METHODS AND RESULTS: Ten post-surgical patients were evaluated where three received no medical therapy, three received metoprolol, three received amiodarone, and one received both metoprolol and amiodarone. The medications led to increases of 37-310 ms in the mean VV interval in treated patients, but much smaller changes in the mean AA intervals in the right and left atria. The mathematical model incorporating a random influence of the concealed conduction parameter was capable of reproducing the histograms of the VV intervals based on the input from the right atrium by systematically searching parameter space. CONCLUSIONS: Changes in the ventricular rate are mainly due to the alteration in the AV nodal properties rather than changes in the atrial rhythm. The medications can display differential effects on the physiological properties of the AV node, and therefore the mathematical model may help to identify novel pharmacological targets.

Aged↗

PubMed2003

Right ventricular outflow-tract fractional shortening: an applicable measure of right ventricular systolic function.

AIMS: Assessment of right ventricular function is important. However, this is not easy to achieve due to the complex anatomy and geometry of the right ventricle, making the evaluation of its function limited. Therefore, a simple reliable and easy method is needed. This study was performed (1) to evaluate the use of right ventricular outflow tract fractional shortening obtained by M-mode echocardiography as a measure of right ventricular systolic function and (2) to determine the relationship between this parameter and other established measurements of right ventricular function such as long axis excursion. METHODS AND RESULTS: Ninety-two consecutive patients referred for echocardiographic assessment of left and right ventricular function, age mean+/-SD was 68+/-14 years, were investigated. Twenty healthy controls, age 46+/-12 years were also studied. M-mode echocardiography was used to measure right ventricular outflow tract fractional shortening and right ventricular long axis excursion. Doppler echocardiography was used for the estimation of right ventricular-right atrial pressure drop and pulmonary artery acceleration time. Right ventricular outflow tract fractional shortening (P<0.0001), right ventricular long axis excursion (P<0.0001) and pulmonary acceleration time (P<0.0001) were reduced in patients compared to controls. Right ventricular outflow tract fractional shortening correlated with long axis excursion (r=0.66 P<0.0001), pulmonary artery acceleration time (r=0.80 P<0.0001) and right ventricular-right atrial pressure drop (r=-0.53 P<0.0001). Right ventricular long axis excursion correlated with right ventricular-right atrial pressure drop though to a lesser significance (r=-0.27 P <0.001). Furthermore, right ventricular outflow tract fractional shortening was reduced in patients with pulmonary hypertension compared to patients without, this difference was not observed in the right ventricular systolic long axis excursion. CONCLUSION: Right ventricular outflow tract fractional shortening provides a simple and non-invasive measure of right ventricular systolic function. In combination with long axis excursion and Doppler velocities they should provide comprehensive assessment of right ventricular function.

Adult↗

PubMed2003

Measuring the arterial input function with gradient echo sequences.

The measurement of the arterial input function by use of gradient echo sequences was investigated by in vitro and in vivo experiments. First, calibration curves representing the influence of the concentration of Gd-DTPA on both the phase and the amplitude of the MR signal were measured in human blood by means of a slow-infusion experiment. The results showed a linear increase in the phase velocity and a quadratic increase in DeltaR(*) (2) as a function of the Gd-DTPA concentration. Next, the resultant calibration curves were incorporated in a partial volume correction algorithm for the arterial input function determination. The algorithm was tested in a phantom experiment and was found to substantially improve the accuracy of the concentration measurement. Finally, the reproducibility of the arterial input function measurement was estimated in 16 patients by considering the input function of the left and the right sides as replicate measurements. This in vivo study showed that the reproducibility of the arterial input function determination using gradient echo sequences is improved by employing a partial volume correction algorithm based on the calibration curve for the contrast agent used.

Algorithms↗