Showing papers on "Cardiac cycle published in 1982"
TL;DR: The function of the valves on the left side of the heart is reviewed, which shows schematically the pressures, flows, and valve positions of the mitral (inflow) and aortic valves of the left ventricle.
Abstract: The function of the valves on the left side of the heart is reviewed in Figure I, which shows schematically the pressures, flows, and valve positions of the mitral (inflow) and aortic (outflow) valves of the left ventricle. Note that the cardiac cycle can be divided into two main parts according to whether the ventricular muscle is contracting (systole) or relaxing (dias tole). During systole, the mitral valve is closed, the aortic valve is open� and the left ventricle forms a common chamber with the aorta. During diastole, the valve configurations are reversed, and the left ventricle forms a common chamber with the left atrium. Note that the pressure difference across the open valve is very small, and that there is no backflow except for a spurt of brief duration associated with the closure movement of the valve. The valves themselves are thin membranous leaflets. To appreciate their remarkable anatomy, see the superb drawings of Netter (1969). Better still, dissect a fresh beef heart (available from wholesale meat markets and some retail stores).
307 citations
TL;DR: In this paper, the authors measured coronary blood flow velocity in an epicardial artery (left anterior descending) and an intramural artery (septal) in open-chest, anesthetized dogs.
Abstract: Knowledge concerning phasic coronary blood flow is based primarily on measurements obtained from epicardial coronary arteries, which, in part, function as capacitors. If present, epicardial capacitance effects could obscure the dynamic nature of phasic intramyocardial perfusion. To analyze this effect of epicardial capacitance, we simultaneously measured coronary blood flow velocity in an epicardial artery (left anterior descending) and an intramural artery (septal) in open-chest, anesthetized dogs. During control conditions, the percentage of total coronary blood flow velocity occurring during diastole per cardiac cycle was significantly greater (P less than 0.05) in the septal artery (92%) than in the left anterior descending artery (75%). Furthermore, blood flow velocity during mid-systole in the septal artery was retrograde (-7.2%), whereas blood flow velocity at this time was antegrade in the left anterior descending artery (+3.5%). Blood flow velocity measurements from small epicardial arteries just before they penetrated into the myocardium revealed a phasic pattern similar to that of the septal artery. This suggests that the phasic blood velocity pattern in penetrating coronary arteries, in general, is different than that in large epicardial arteries. During vasodilation following nitroglycerin, dipyridamole, or a 20-second occlusion of the left main coronary artery, the retrograde component of mid-systolic blood velocity persisted in the septal artery, despite large increases (300-400%) in the mid-systolic antegrade component of blood flow velocity in the left anterior descending artery. These qualitative and quantitative differences in phasic blood flow velocity between intramural and large epicardial arteries are best reconciled by postulating the existence of a significant coronary capacitor.
184 citations
Patent•
14 Jul 1982
TL;DR: In this article, a heart valve prosthesis incorporating a dynamic stiffener element is disclosed, which allows normal movement of the annulus during the cardiac cycle while providing mechanical support to the valve annulus so as to maintain the valve leaflets in proper physiological alignment.
Abstract: A heart valve prosthesis incorporating a dynamic stiffener element is disclosed. The prosthesis is adapted for securement to the annulus of an atrioventricular valve and has the characteristic of allowing normal movement of the annulus during the cardiac cycle while providing mechanical support to the valve annulus so as to maintain the valve leaflets in proper physiological alignment. The stiffener element has a plurality of reciprocating members allowing it to be modifiable in shape so as to be capable of assuming the optimum shape for a particular heart valve.
180 citations
TL;DR: The hemodynamic parameters of normal hemodynamic function during early embryonic development are defined: blood flow increases geometrically with each embryo stage but remains constant when normalized for embryo weight, vascular resistance and cardiac work increases in proportion to embryo weight.
Abstract: We report the hemodynamic parameters of stage 18, 21, 24, and 27 chick embryos (from 3 to 5 days of incubation). Dorsal aortic blood velocity and mean vitelline artery blood pressure are measured with a 20 MHz pulsed-Doppler meter and servo-null pressure system respectively. We also measure heart rate, dorsal aortic diameter and embryo weight of each developmental stage. From these data, we calculate mean dorsal aortic blood flow, mean dorsal aortic blood flow per cardiac cycle, mean dorsal aortic blood flow per milligram embryo weight, vascular resistance and cardiac work. Blood flow increases geometrically with each embryo stage but remains constant when normalized for embryo weight. Mean arterial pressure increases linearly and vascular resistance decreases geometrically. Cardiac work increases in proportion to embryo weight. These results define the parameters of normal hemodynamic function during early embryonic development.
118 citations
TL;DR: Cardiac index was higher during A-V sequential pacing than during ventricular pacing for every patient at paced rates of 75 to 100 beats/min and the increase in cardiac index in an individual patient did not correlate with baseline characteristics including functional class, cardiothoracic ratio, resting ejection fraction, cardiac index or balloon-occluded pulmonary wedge pressure.
Abstract: Acute atrioventricular (A-V) sequential pacing was compared with ventricular pacing in seven men with symptomatic left ventricular failure (New York Heart Association functional class III and IV) and depressed left ventricular ejection fraction (mean 29 percent, range 18 to 40). Cardiac index was higher during A-V sequential pacing than during ventricular pacing for every patient at paced rates of 75 to 100 beats/min. The mean increment was 17 percent (range 10 to 37) at a paced rate of 75 beats/ min, 23 percent (range 8 to 45) at a paced rate of 85 beats/min and 29 percent (range 19 to 55) at a paced rate of 100 beats/min. The increase in cardiac index in an individual patient did not correlate with baseline characteristics including functional class, cardiothoracic ratio, resting ejection fraction, cardiac index or balloon-occluded pulmonary wedge pressure. Arterial pressure varied from beat to beat during ventricular pacing because of the changing relation of atrial to ventricular systole. When an atrial contraction preceded a ventricular paced beat by a physiologic interval intraarterial pulse pressure uniformly increased. That increase correlated strongly (r = 0.993) with the increase in cardiac index that occurred during A-V sequential pacing. Measurement of the pulse pressure during A-V dissociation is a simple technique that may be useful for predicting the degree of improvement in cardiac output expected with methods of pacing that restore A-V synchrony.
107 citations
TL;DR: The results indicate that quantitatively significant degradation of reconstructions of true tracer distribution occurs in cardiac PET due to both intrinsic cardiac and respiratory induced motion of the heart, and suggest that avoidance of or minimization of these influences can be accomplished by gating with respect to both the cardiac cycle and respiration or by employing brief scan times during breath-holding.
Abstract: The potential influence of physiological, periodic motions of the heart due to the cardiac cycle, the respiratory cycle, or both on quantitative image reconstruction by positron emission tomography (PET) has been largely neglected. To define their quantitative impact, cardiac PET was performed in 6 dogs after injection of /sup 11/C-palmitate under disparate conditions including: normal cardiac and respiration cycles and cardiac arrest with and without respiration. Although in vitro assay of myocardial samples demonstrated that palmitate uptake was homogeneous (coefficient of variation . 10.1%), analysis of the reconstructed images demonstrated significant heterogeneity of apparent cardiac distribution of radioactivity due to both intrinsic cardiac and respiratory motion. Image degradation due to respiratory motion was demonstrated in a healthy human volunteer as well, in whom cardiac tomography was performed with Super PETT I during breath-holding and during normal breathing. The results indicate that quantitatively significant degradation of reconstructions of true tracer distribution occurs in cardiac PET due to both intrinsic cardiac and respiratory induced motion of the heart. They suggest that avoidance of or minimization of these influences can be accomplished by gating with respect to both the cardiac cycle and respiration or by employing brief scan times during breath-holding.
105 citations
TL;DR: The data suggest that the pattern of sinus node responses during transitions of arterial pressure results from a complex interplay among several factors, including baroreflex responsiveness, base-line heart rate, the rate decay of barore Flex inhibition, and the biphasic nature of sinu node responses to inhibitory cholinergic interventions.
Abstract: When arterial pressure rises spontaneously, baroreceptor areas are presented with repetitive stimuli of progressively increasing intensities. We simulated rising arterial pressure in 18 healthy young adults by applying trains of repetitive, ramped, R-wave-coupled neck suction, and we related P-P interval responses to intensities of stimuli with least-squares linear regression. We found that the P-P interval response to the stimulus train we used is immediate and highly linear (most correlation coefficients were above 0.90). In studies in which the base-line heart rate was less than 75 beats/min, cardiac inhibition was maximal in the cardiac cycle in which the stimulus was delivered. Decay of inhibition commences rapidly after the end of baroreceptor stimulation and proceeds with time constants that are independent of maximum levels of inhibition. P-P interval shortening (cardioacceleration) comprises an integral feature of baroreflex responses, such that inhibitory stimuli set in motion oscillations of heart period above and below base-line levels. Our data suggest that the pattern of sinus node responses during transitions of arterial pressure results from a complex interplay among several factors, including baroreflex responsiveness, base-line heart rate, the rate decay of baroreflex inhibition, and the biphasic nature of sinus node responses to inhibitory cholinergic interventions.
95 citations
TL;DR: The analysis yields the following new information about the contracting left ventricle: three principal directions of deformation and the relative length change along these directions: the axis and angle of rotation, and relative volume.
Abstract: No approach to describing the heart's dynamic geometry has been widely adopted, probably because all require questionable assumptions of chamber shape, symmetry, or placement of the measuring devices. In other words, these approaches require assumptions about shape to reach conclusions about shape. We present an analysis that avoids such assumptions and provides an objective description of how the left ventricle deforms and rotates during the cardiac cycle. We only assume that the deformation of the left ventricular cavity is homogeneous, and explicitly validate this assumption. Our analysis yields the following new information about the contracting left ventricle: three principal directions of deformation and the relative length change alone these directions: the axis and angle of rotation, and relative volume. All these changes are referenced to the ventricle's configuration at end-diastole. We instrumented 13 dogs with tantalum screws without opening their chests. During systole, the three principal directions of deformation essentially are aligned along apex-base, anterior-posterior, and septum-free wall directions. There is little length change in the apex-base direction. The anterior and septal principal directions do not remain fixed with respect to the heart's anatomy during systole. During isovolumic relaxation and early filling, systolic shape changes are reversed. During slow filling, only small shape changes occur. Opening the pleura or performing a sternotomy and pericardiectomy makes the heart change orientation within the chest, but does not alter the magnitude of shortening, relative to the left ventricle's end-diastolic configuration.
64 citations
TL;DR: Age related increases in left ventricular cavity dimension and wall thickness during the rapid growth period of childhood occurred in such a way thatleft ventricular architecture (H/R ratio) remained unchanged, which may account for the constancy of regional and cavity systolic function.
Abstract: We assessed the effects of age related changes in chamber size, wall thickness, and heart rate of left ventricular function in 78 normal children, aged 1 1/2 to 12 1/2 years, using computer analysis of their left ventricular echocardiograms. Left ventricular cavity size and wall thickness increased linearly with age. Left ventricular fractional shortening, percentage of wall thickening, and the ratio of end-diastolic wall thickness to cavity radius (H/R ratio) did not change with age. Peak Vcf correlated with heart rate and the decrease in heart rate with age resulted in the progressive fall in peak Vcf, while peak rate of left ventricular was thickening remained constant. The peak rate of increase in left ventricular cavity dimension in early diastole varied inversely with heart rate, but independently of cavity size, increasing throughout childhood. The peak rate of wall thinning also increased with age, correlating with wall thickness and not heart rate. Thus, age related increases in left ventricular cavity dimension and wall thickness during the rapid growth period of childhood occurred in such a way that left ventricular architecture (H/R ratio) remained unchanged. This may account for the constancy of regional and cavity systolic function. The greater dependence of diastolic cavity function on heart rate may be explained by the disproportionately greater effect of cardiac cycle length on the duration of diastole and systole.
36 citations
TL;DR: With cross-sectional echocardiography, the constellation of abnormalities that give rise to lack of offsetting of the atrioventricular valves can be reliably identified.
Abstract: Ninety two patients with both atrioventricular valves attached to the atrial septum, roofing a perimembranous inlet ventricular septal defect, were assessed by cross-sectional echocardiography. In the group, 42 had an isolated perimembranous inlet ventricular septal defect, 31 had atrioventricular discordance, nine an atrioventricular septal defect with intact interatrial septum, and 10 a straddling atrioventricular valve. In all but those with an atrioventricular septal defect the left atrioventricular valve had the appearance of a morphologically mitral valve. In the former lesion the atrioventricular junction was "sprung" and a cleft between the anterior and posterior bridging leaflets was identified in all. A straddling valve was identified by tensor apparatus from one atrioventricular valve in both ventricular chambers. Atrioventricular discordance was diagnosed by identifying the systemic and pulmonary venous atria and then assessing the morphology of the draining atrioventricular valves. Thus, with cross-sectional echocardiography, the constellation of abnormalities that give rise to lack of offsetting of the atrioventricular valves can be reliably identified.
29 citations
TL;DR: The closing behaviour of the valve as determined in animal experiments under different hemodynamic circumstances showed reasonable agreement with the valve closure as predicted by theory, however, due to the simplifications assumed in the model the theoretical description must be used tentatively, especially with large pressure changes within the valve orifice during the cardiac cycle, with low peak flows or with high Strouhal numbers.
TL;DR: The results suggest that sustained ventricular tachycardia is frequently associated with stable reentrant pathways through areas of critically slow conduction, and specific, orderly and reproducible patterns were seen more often than chaotic “localized fibrillation.”
Abstract: Sustained ventricular tachycardia, consisting of a regular rhythm with 100 or more consecutive ectopic beats, was studied in 14 dogs anesthetized with sodium pentobarbital 4 days after occlusion of the left anterior descending coronary artery. Electrocardiograms were recorded as well as composite (epicardial) and electrode catheter (endocardial) electrograms from the area of infarction. Sustained ventricular tachycardia was induced by atrial or ventricular pacing, or both (180 to 360/min) in 3 of 21 untreated dogs and 11 of 19 dogs treated with methylprednisolone (30 mg/kg body weight, intravenously) given at the time of coronary occlusion. Sustained ventricular tachycardia with two or more QRS configurations occurred in nine dogs, and seven dogs showed both right and left bundle branch block patterns. Ventricular tachycardia was associated with continuous electrical activation in composite epicardial electrograms that bridged interectopic intervals and showed regular patterns of electrical activation that were reproducible with each cardiac cycle. Interectopic activation patterns were distinctive for each QRS pattern. In some instances portions of activation patterns for two different configurations were similar; however, the electrographic configuration immediately before the onset of the QRS complex always differed. During ventricular tachycardia, spontaneous alterations in QRS configuration were observed in two dogs and were induced by atrial or ventricular pacing in five dogs. In all cases changes in QRS configuration during sustained ventricular tachycardia were preceded by changes in diastolic activation patterns. The results suggest that sustained ventricular tachycardia is frequently associated with stable reentrant pathways through areas of critically slow conduction. In this experimental preparation, specific, orderly and reproducible patterns were seen more often than chaotic “localized fibrillation.” Different QRS configurations after changes in interectopic patterns of continuous electrical activation are consonant with changes in specific reentrant pathways through the region of slow conduction.
TL;DR: The results indicate that a transient increase in cardiac metabolic demand is followed immediately by a compensatory coronary vasodilation that occurs within the same cardiac cycle.
Abstract: This study was undertaken to determine if coronary blood flow can be regulated in response to a transient increase in cardiac metabolic demand. Eight conscious dogs with experimentally produced complete heart block, a chronically implanted electromagnetic flow probe on the left circumflex coronary artery, and fluid-filled catheters for measurement of left ventricular and aortic pressures were studied. At a paced heart rate of 60 beats/min, a single ventricular extra-stimulus was introduced with a delay of 150-200 msec from the preceding R-wave. The extra-stimulus produced a ventricular extra-activation, but not a discrete mechanical extra-systole. The ensuing beats exhibited systolic potentiation, manifest by a 50 +/- 8% increase from control in maximum left ventricular dp/dt in the first potentiated beat, presumably accompanied by increased myocardial oxygen demand. In the diastole immediately following the first potentiated systole, the coronary vascular resistance index (mean aortic pressure/mean coronary flow in that diastole) fell significantly from control by 12 +/- 2%. The results indicate that a transient increase in cardiac metabolic demand is followed immediately by a compensatory coronary vasodilation that occurs within the same cardiac cycle.
TL;DR: Results of transmural myocardial blood flow and intramyocardial pressure measured in the same animal are identical with those of others, except for the reduction in subendocardialBlood flow compared with the layers just epicardial to that.
Abstract: Transmural myocardial blood flow was measured with microspheres in systole and in diastole, along with intramyocardial pressure, in seven anaesthetised horses. Intramyocardial pressures were measured with a miniature manometer implanted in the tip of a 16-gauge needle. Peak systolic intramyocardial pressure decreased from subendocardium to subepicardium and never exceeded intraventricular pressure. Systolic blood flow decreased from epicardium to endocardium where it did not differ from zero. Diastolic blood flow increased from epicardium to subendocardium, but then decreased in the most endocardial layer to a level not different from the immediate subepicardial layer. The horse was a useful model for studying these parameters because the ventricular walls are so thick and the heart rate is so slow that injections may be made during various phases of the cardiac cycle. These results of transmural myocardial blood flow and intramyocardial pressure measured in the same animal are identical with those of others, except for the reduction in subendocardial blood flow compared with the layers just epicardial to that.
TL;DR: The basis for pulsatile pressure and flow wave analysis and representation by the aortic input impedance spectrum has been reviewed in detail and the rational for consideration of this complex function as the total systemic vascular load that opposes left ventricular ejection is developed.
TL;DR: Fifteen patients with clinically normal function of a St. Jude mitral valve prosthesis were studied with two dimensional and M mode echocardiography, Cinefluoroscopy and phonocardiographers 8 to 292 days after valve replacement to permit in vitro simulation of valve echograms under a variety of conditions.
Abstract: Fifteen patients with clinically normal function of a St. Jude mitral valve prosthesis were studied with two dimensional and M mode echocardiography, Cinefluoroscopy and phonocardiography 8 to 292 days after valve replacement. The valve was readily imaged from the left sternal edge and cardiac apex in all patients. On two dimensional echocardiography from the long axis and four chamber views, minimal end-diastolic and endsystolic distances between the interventricular septum and prosthetic valve were 18 ± 5 mm and 13 ± 3 mm, respectively (mean ± standard deviation). On M mode echocardiography both leaflets were imaged throughout the cardiac cycle from the left sternal edge and their motion relative to the valve ring and to one another was easily evaluated. The apical transducer position permits quantitative assessment of individual leaflet motion. Maximal individual diastolic leaflet excursion was 8.7 ± 1 mm and the velocity of leaflet opening and closure was 364 ±103 and 678 ±115 mm/s, respectively. Asynchronous early closure of the posterior leaflet was observed during long cardiac cycles in six of seven patients with atrial fibrillation; the seventh patient had a rapid ventricular response and no long cardiac cycles. Diastolic fluttering of one or both leaflets was also seen during atrial fibrillation after rotation of the patient from the supine to the left lateral decubitus position. Three of the six patients with asynchronous leaflet closure underwent Cinefluoroscopy, and similar leaflet behavior was documented in all. An atrial systolic wave was inscribed in the valve echogram in six of eight patients with sinus rhythm. Phonocardiography recorded prosthetic valve opening and closing sounds occurring 60 ± 20 ms after aortic closure and 61 ± 12 ms after the QRS complex, respectively. The prosthetic valve opening and closure sound amplitude ratio was 0.11 ± 0.06. A clear plexiglass water bath phantom was fitted to a pulse duplicator and constructed so as to permit in vitro simulation of valve echograms under a variety of conditions. With this method, it was possible to reproduce or approximate all images obtained in patients from both echocardiographic transducer positions.
TL;DR: It was concluded that analysis of the subcostal RA wall echocardiogram is a new, helpful noninvasive approach in the diagnosis of cardiac arrhythmias.
Abstract: The M-mode echocardiogram of the right atrial (RA) wall can be easily recorded in each person from the subcostal location. In a normal RA wall motion pattern, atrial contraction is represented by a markedly prominent posterior motion. The presence or absence of atrial contractions in the subcostal RA wall echocardiogram, their amplitude, and their timing may help in the diagnosis of cardiac arrhythmias with the simultaneously recorded non-diagnostic electrocardiogram. Flat and hidden P waves can be accurately identified throughout the cardiac cycle. It is possible to distinguish between atrial, ventricular, and nodal premature beats and to recognize atrial fibrillation, atrial flutter, paroxysmal atrial tachycardia, paroxysmal atrial tachycardia with block, atrioventricular (AV) nodal tachycardia, and supraventricular tachycardias with aberrant ventricular conduction. The diagnosis of wandering pacemaker, AV dissociation, sinoatrial block, and AV block is facilitated. On the basis of study of 60 patients with various rhythm disturbances, it was concluded that analysis of the subcostal RA wall echocardiogram is a new, helpful noninvasive approach in the diagnosis of cardiac arrhythmias.
TL;DR: Echocardiography may offer a non-invasive method to estimate the prognosis in isolated right bundle-branch block because of the effect of the electrical delay on the mechanical events of right ventricular systole.
Abstract: Twenty-seven patients with complete right bundle-branch block as the only abnormal finding were studied using high speed M-mode echocardiography to determine the effect of the electrical delay on the mechanical events of right ventricular systole. Pulmonary valve opening (PVOm) was delayed in all cases. In some the delay was mainly between mitral valve closure (MVC) and tricuspid valve closure (TVC), and this was designated proximal block. In the others the main delay was between tricuspid valve closure and pulmonary valve opening and this was designated distal block. The patients were divided into those with proximal and those with distal block by calculating the ratio TVC-PVOm/MVC-TVC. Twelve out of 13 of those with distal delay but only one out of 14 of those with proximal delay had episodes of syncope or near syncope. These results are consistent with previous theories about the pathophysiology of right bundle-branch block. Echocardiography may offer a non-invasive method to estimate the prognosis in isolated right bundle-branch block.
TL;DR: The sequential cardiac area curve was useful in evaluating instantaneous changes of cardiac dimension, extent of ventricular contraction, and regional dyssynergy in patients with recent or remote myocardial infarction.
TL;DR: In this paper, high-speed M-mode echocardiography was used in the usual projections in eight patients during tachycardia to identify atrioventricular dissociation, a feature heavily in favor of a diagnosis of VT.
TL;DR: Mechanical probing and vascular occlusion indicated that cardiovascular receptors in the turtle were located in the proximal common pulmonary artery including the bulbus cordis region.
Abstract: This study was undertaken to characterize cardiovascular receptors in the turtle, Pseudemys scripta, with particular attention being given to neural activity changes associated with alterations in blood pressure. Vagal afferent nerve traffic, synchronous with heart contractions, was recorded in anesthetized artificially ventilated turtles. Action potentials, from receptors that fired regularly during each heart cycle, occurred during ventricular systole. Mechanical probing and vascular occlusion indicated that these receptors were located in the proximal common pulmonary artery including the bulbus cordis region. Bolus injections of saline into the ventricle or the common pulmonary artery caused immediate but transient increases in cardiac synchronous traffic. Prolonged elevation of arterial and ventricular blood pressure, by either saline injection or arterial occlusion, caused increases in receptor discharge of the same duration as the pressure increases. Although these receptors could participate in the regulation of the systemic and the pulmonary circulation, the physiological role for them is presently unknown.
TL;DR: Cardiac structures are continuously moving during the cardiac cycle so that constantly changing acoustical interfaces are being recorded by the theoretically static echographic beam and horizontal cardiac motion is a significant physiologic phenomenon of potential clinical importance.
Abstract: Cardiac structures are continuously moving during the cardiac cycle so that constantly changing acoustical interfaces are being recorded by the theoretically static echographic beam. The characteristic movement of the base of the heart toward the apex in systole appears as horizontal motion when imaged in two dimensional echocardiographic parasternal long axis views. The quantitative characteristics of horizontal motion were studied in 50 control patients, 25 patients with decreased cardiac output, 20 with volume overload and 10 with pericardial effusion. The angle of cardiac shift at the aorto-interventricular septal junction was 8 ± 2 ° (mean ± standard deviation) in control patients, and this change constituted 21 ± 6 percent of the area within the arc containing the standard M mode information. Horizontal shifts were decreased in patients with decreased cardiac output (4 ± 2 °; p With use of the concept of horizontal motion, the interventricular septal hinge point was noted to be in the area of the membranous interventricular septum, rather than at the junction of the upper and middle thirds of the interventricular septum in 80 percent of normal subjects, 72 percent of patients with decreased cardiac output, 60 percent of those with pericardial effusion, 52 percent of those with left-sided volume overload and 40 percent of those with right-sided volume overload. The concept of horizontal cardiac motion was also pertinent to the interpretation of aortic valve opening, the transposition of aortic root information to apparent left ventricular outflow tract level, one form of pseudosystolic anterior mitral motion, abnormal left atrial echoes, echoes mimicking flail posterior mitral leaflet and interpretation of left atrial wall motion at the left atrial-left ventricular junction. In conclusion, horizontal cardiac motion is a significant physiologic phenomenon of potential clinical importance. It causes important changes in the echographic recording of acoustical information.
TL;DR: It can be surmised that the early systolic sound observed in these patients may be related to max- imum excursion of the opening motion of the car- bon leaflets or turbulence created by transvalvular flow during left ventricular systole.
Journal Article•
TL;DR: In the evaluation of mitral valve dysfunction, PDE as a non-invasive technique is of high specificity and sensitivity as compared with the hemodynamic results of invasive procedures.
Abstract: 67 patients (pts)--20 with intact cardiac valve function, 15 with pure mitral stenosis, 20 with both mitral valve insufficiency and stenosis, 12 pts with pure mitral incompetence - have been investigated by non-invasive pulsed Doppler-echocardiography (PDE) previous to invasive right and left heart catheterization. The following criteria for evaluation of the PDE registrations are adopted: 1) Time-related correlation of ECG and flow velocity. 2) Formal analysis of the flow-velocity tracings. 3) Turbulence formation. 4) Maximum duration of flow. In pure mitral insufficiency, systolic turbulence formation is detected within the left atrium, which is present according to the severity only locally or throughout the entire left atrium. We calculated a specificity for the diagnosis of mitral incompetence of 94% and a sensitivity of 78%. In mitral stenosis a severity-dependent ventricular inflow velocity is prevalent - with an insidious onset until a dome-like or saw-tooth-like profile. Grading for severity of mitral stenosis can be performed as follows: the time from onset to maximum flow velocity of the diastolic inflows is measured and related to the time period of the cardiac cycle. A specificity of PDE for mitral stenosis of 88% and a sensitivity of 91% have been found. PDE is also being applied for assessment of hemodynamic efficacy of prosthetic mitral-valve replacement. In the evaluation of mitral valve dysfunction, PDE as a non-invasive technique is of high specificity and sensitivity as compared with the hemodynamic results of invasive procedures.
TL;DR: A noninvasive ultrasonic technique has been designed to measure the hemodynamic variables associated with human right ventricular diastole, and compared the measurements with data derived from an alternative technique: forward angiocardiography taken during cardiac catheterization.
Abstract: A noninvasive ultrasonic technique has been designed to measure the hemodynamic variables associated with human right ventricular diastole. For convenience, diastole is divided into five phases: rapid filling, slow filling, early resting, atrial systole, and late resting phases. The technique measures the velocity with which blood enters the ventricule during each phase, and relates these measurements to ventricular wall motion. The technique has been evaluated by comparing the measurements with data derived from an alternative technique: forward angiocardiography taken during cardiac catheterization. In this procedure, blood containing dye can be followed through the ventricle by X-ray, and velocity measurements can be made from the cinefluoroscopic films. Cinefluoroscopy has also defined potential problems related to turbulence and heart motion. Ultrasonic and cardiac catheterization measurements agreed well. The ultrasonic equipment can be carried by hand from one room to another is inexpensive, and is readily available. This equipment can be used on the same subject repeatedly without discomfort or danger, and can be used during exercise.
Journal Article•
TL;DR: The echogram of the mitral valve showed a diminution of the E--F slope, demonstrating that the filling rate in the protodiastole decreases in the advanced age, and the isovolumic relaxation time, estimated by means of the apexcardiogram, was prolonged in the aged subjects.
Abstract: The dynamics of the heart contraction was studied on 126 subjects of different age (3rd--8th decades), using the classical noninvasive method, and the electrocardiogram, the phonocardogram and the external carotid arterial pulse were simultaneously recorded. In a smaller number of cases there was recorded the apexcardiogram or the echogram of the mitral valve. There was ascertained a prolongation of the pre-ejection period (PEP) with advance in age, while the left ventricular ejection time (LVET) was not significantly modified. The LVET/PEP ratio decreased significantly with age. The isovolumic relaxation time, estimated by means of the apexcardiogram, was prolonged in the aged subjects. The echogram of the mitral valve showed a diminution of the E--F slope, demonstrating that the filling rate in the protodiastole decreases in the advanced age. This decrease may reflect a reduction with age in the rate of the opening movement of the mitral valve imposed by the inherent modifications either of the mitral valve or of the left ventricle. The delay of the protodiastolic filling of the ventricle can be attributed to the slowing down of the ventricle relaxation or to the increase of the left ventricle wall stiffness in the aged.
TL;DR: The results suggest that the interval between end systole and end ejection of the left ventricle in vivo is also variable depending on changes in the arterial loading conditions, ventricular contractility and heart rate.
Abstract: Although the end of ejection of the left ventricle has been generally accepted as almost synonymous with the end of mechanical systole of the ventricle, recent experimental studies showed the cases in which end ejection lagged markedly behind end systole as identified by the time at which the ventricular pressure-volume data point reached the peak isovolumic pressure-volume relation curve. To obtain a better insight into cardiovascular conditions of the delayed end ejection, a computer simulation study was carried out in which the performance of a time-varying elastance model of the ventricle connected with a modified Windkessel model of the arterial load was analyzed. Any change in the Windkessel parameters, ventricular contractility and heart rate sensitively shifted end ejection relative to end systole. Although end ejection coincided with end systole under limited circumstances, end ejection variably lagged behind end systole undermost circumstances. These results suggest that the interval between end systole and end ejection of the left ventricle in vivo is also variable depending on changes in the arterial loading conditions, ventricular contractility and heart rate.
Journal Article•
TL;DR: The center of the gravity of the left ventricular cavity in myocardial infarction showed the tendency to shift towards the infarcted region, suggesting the possibility that the location of asynergic area can be detected by determining the direction of thegravity center shift during systole in patients with a single infarctions.
Abstract: Quantitative assessment of left ventricular asynergy in myocardial infarction was made by computer analysis of the two-dimensional echocardiogram Short-axis cross-sectional images of the left ventricle at the levels of the mitral valve, papillary muscle and apex were recorded by a phased array sector scanner in 20 patients with myocardial infarction and ten normal controls End cardial and epicardial outlines at end-diastole and end-systole were traced and analyzed by a computer system Short-axis cross-sectional images of the left ventricle were divided equally into octants and analyzed with a fixed external reference system, using the center of gravity of end-diastolic left ventricular cavity and the axis intersecting this and the right side of the posterior interventricular septum as the reference point and line Segmental hemiaxis, area, wall thickness and those changes during cardiac cycle were measured and calculated in each octants Regional contractility of the left ventricle was evaluated by systolic percent change of segmental hemiaxis, area and wall thickness These parameters were significantly reduced in the infarcted segments documented by left ventriculography and electrocardiography The area method is better than the hemiaxis system in both reproducibility and variability The center of gravity of the left ventricular cavity determined by the computer shifted slightly towards the anterior wall during systole in normal subjects, possibly reflecting anterior swinging motion of the entire heart The center of the gravity of the left ventricular cavity in myocardial infarction showed the tendency to shift towards the infarcted region, suggesting the possibility that the location of asynergic area can be detected by determining the direction of the gravity center shift during systole in patients with a single infarction This finding gives a basis of using the fixed reference system for the detection of asynergy The use of computers for the analysis of short-axis two-dimensional echocardiographic images is very useful for the quantification of regional contractility of the left ventricle in a clinical setting
01 Jul 1982
TL;DR: Methods are presented that measure the dynamic geometry of the working, isolated canine heart by means of ultrasound-velocity tomography techniques and results of regional contraction and relaxation patterns are presented.
Abstract: Many models for the study of the pump function of the heart emphasize the
importance of cardiac geometry and detailed dimensional data. Because of the
lack of accurate measuring techniques, approximate geometries such as shells of
revolution have been applied. In this study, methods are presented that measure
the dynamic geometry of the working, isolated canine heart by means of ultrasound-
velocity tomography techniques. In addition, cardiac dimensions, intramural deformations, and fiber shortening have been measured dynamically in the in situ canine heart throughout the cardiac cycle with implanted tadiopaque markers and biplane roentgen techniques. Results of regional contraction and relaxation patterns are presented. Epicardial fiber shortening between apex and
base were computed and found to be dependent on the duration of the preceding RR interval.
TL;DR: Using M-mode echocardiography and simultaneous apex cardiography it is possible to show abnormal ventricular response to pressure changes during the isovolumic periods, to quantify the abnormality and to detect early abnormal muscle behaviour before it becomes visible on conventional ultrasound recordings.
Abstract: The relationship between left ventricular dimension measured using M-mode echocardiography and simultaneous apex cardiography has been studied in 69 normal subjects (2 groups) and 159 patients with heart disease (6 groups). A loop was formed by plotting the apex cardiogram, which is related to ventricular wall stress, against ventricular dimension. Abnormalities in ventricular function due to shape or volume changes in the isovolumic phases of the cardiac cycle produced characteristic alterations in the loop pattern. These changes were measured and the results for different groups compared. Normal subjects were divided into two age groups (13–38, 40–78) and no significant differences were found between them. In the heart-disease patients, 25% had an abnormal decrease in dimension during isovolumic contraction and 25% had an abnormal increase during isovolumic relaxation. When the downstroke of the apex cardiogram was differentially analysed, it was possible to show that 60% of heart-disease patie...