Richard H. Marcus

The spectrum of severe rheumatic mitral valve disease in a developing country. Correlations among clinical presentation, surgical pathologic findings, and hemodynamic sequelae.

Bland and Jones [1], in their benchmark report on rheumatic fever and rheumatic heart disease in 1951, documented a mortality rate of 50% by age 20 years among young patients presenting with rheumatic mitral valve disease before 1920. With the advent of antibiotics, the incidence and severity of rheumatic fever and acute rheumatic carditis have declined markedly in the Western world [2, 3]. In the United States, the decline in rheumatic disease resulting from antimicrobial therapy was so dramatic that several important issues relating to the natural history of this condition have never been resolved. Specifically, the high early mortality rate among young patients with acute rheumatic carditis [1, 4] has not been explained. In this context, Bland and Jones [1] did report a high prevalence of mild mitral regurgitation early in the course of the disease but felt that this lesion was benign. The prevalence and natural history of pure, severe rheumatic mitral regurgitation have not been established, and its unique surgical anatomy has not been well characterized. In developing areas, where predisposing factors to rheumatic fever persist and prophylactic penicillin therapy is often inadequate, acute rheumatic carditis still frequently follows a fulminant course, resulting in death or severe disability at an early age [5-8]. In South Africa, the sociopolitical situation is such that abject poverty and deprivation are often juxtaposed with sophisticated tertiary care services. The availability of the latter, specifically cardiac surgery, for patients with this disease permitted us to analyze clinical, hemodynamic, and surgical pathologic data that had not been previously correlated. Methods We retrospectively studied 748 consecutive patients with rheumatic heart disease who had mitral valve surgery between 1983 and 1986 at Baragwanath Hospital in South Africa. All patients were blacks living either in townships in the environs of the hospital (equivalent to inner-city areas in the metropolitan United States) or in rural areas. Eleven patients in whom concurrent infective endocarditis or primary degenerative leaflet disease (1 patient) confounded evaluation of the hemodynamic severity of the rheumatic lesion itself were excluded from the analysis. Of the remainder, 520 were female and 217, male. Patients ranged in age from 4 to 73 years (mean, 27 13 years [SD]; median, 25 years); 271 (37%) were 20 years of age or younger. All were in New York Heart Association (NYHA) class 3 or 4 and receiving maximal medical treatment. Preoperative Classification of Valve Lesions Before surgery, all patients were examined independently by at least two cardiologists. Mitral valve lesions were classified as purely regurgitant, purely stenotic, or mixed according to recognized clinical, radiologic, and echocardiographic criteria [9]. Mitral regurgitation was considered to be pure when associated with unrestricted valve leaflet excursion and a normal mitral orifice area as assessed by two-dimensional echocardiography. Pure mitral stenosis was diagnosed when no clinical or echocardiographic evidence for regurgitation was found. Mixed mitral valve disease was diagnosed when features of both regurgitation and stenosis were present. Cases in which discordance existed among clinical, hemodynamic, and surgical pathologic assessments were excluded from the analysis. Surgical Evaluation Hemodynamic Assessment The hemodynamic severity of valve lesions was confirmed by measurements of left atrial, left ventricular, and right ventricular pressures using fluid-filled catheters connected through strain gauge transducers (Statham, Oxnard, California) to a multichannel recorder (Honeywell Meddars, Lenexa, Kansas). The transmitral end-diastolic gradient (timed according to the R wave on the electrocardiogram) was determined by analysis of simultaneous left atrial and left ventricular pressure recordings. The ratio of left atrial V wave to mean left atrial pressure was calculated as an index of the hemodynamic severity of mitral regurgitation [10]. In 74 patients (10%), pressure measurements were not obtained for technical reasons or because of hemodynamic instability. Surgical Anatomy After cardiotomy, mitral valves were examined independently by two experienced surgeons according to a standard protocol, implemented in all patients having rheumatic valve surgery at Baragwanath Hospital between 1983 and 1986 at the instigation of one of the surgeons who was then doing research in this area. Valve leaflets were assessed for their pliability as well as for evidence of retraction (scarring) or calcification. Valve commissures were evaluated for evidence of fusion. Mitral valve prolapse was diagnosed at operation if the free edge of one or more scallops of a leaflet, almost invariably the anterior, could be retracted toward the left atrium beyond the free margin of the complementary leaflet and above the plane of the mitral annulus without applying tension to the chordae tendineae [5, 11]. The size of the mitral annulus and the length of the chordae tendineae were assessed. The size of the mitral annulus was graded by inspection using a 4-point scale from 0 (normal size) to 3+ (markedly dilated). In addition, the annular diameter was measured using valve sizers in all patients who had insertion of mechanical prostheses or valve rings (Carpentier, Santa Ana, California). The chordae tendineae were assessed for length (elongated, shortened, or normal), fusion, and evidence of rupture. Among patients who had mitral valvuloplasty, the requirement for chordal shortening procedures was used as ancillary evidence for the presence of chordal elongation. Surgical Classification of Valve Lesions The hemodynamic and anatomic features that were considered diagnostic of pure mitral regurgitation included absent or minimal end-diastolic gradient across the mitral valve; pliable, freely mobile mitral valve leaflets; and absence of commissural fusion or subvalvular disease. Pure mitral stenosis was confirmed at surgery in patients with no clinical or echocardiographic evidence for mitral regurgitation when there was marked commissural fusion and a substantial transmitral end-diastolic gradient. Assessment of Rheumatic Activity Clinical Evaluation Rheumatic activity was diagnosed preoperatively when there was serologic evidence for antecedent group A -hemolytic streptococcal infection in addition to at least two major (or one major plus two minor) criteria of acute rheumatic fever (revised Jones criteria) [12]. Macroscopic Evaluation Valves were examined during surgery for the macroscopic features of active rheumatic carditis that have been described [5, 13]: fibrinous pericarditis with epicardial involvement; pinhead vegetations on the free edges of the valve leaflets in the absence of infective endocarditis; and nonspecific signs of acute inflammation including edema, erythema, and hemorrhage within leaflet tissue. Histologic Evaluation Where sufficient cardiac tissue was available for adequate histologic assessment, the following light microscopic findings were used as criteria of rheumatic activity [13, 14]: fibrinoid necrosis in valve leaflet or annular tissue; polymorphonuclear or histiocyte infiltration; edema; and neovascularization. Analysis of Data For continuous variables, such as pressure data, analysis of variance with the Tukey allowance for multiple comparisons was used to compare three or more groups, and two-sample t-tests were used in instances when only two groups were compared. For categorical data, such as the prevalence of mitral valve prolapse, chi-square tests were used. Three x two contingency tables were constructed to establish the presence of intergroup differences; individual groups were then compared using the Bonferroni correction for multiple comparisons. Statistical differences were recorded using two-tailed P values. Results Correlation between Preoperative and Surgical Classification of Valve Lesions Surgical and preoperative classifications of valve lesions were in agreement in 714 of 737 (97%) cases. The 23 patients in whom discordance existed between the preoperative and surgical assessment of the mitral valve lesion were excluded from the analysis. Relative Prevalence of Valve Lesions When the entire patient population was considered, the three types of mitral valve lesion were documented with similar frequency: Two hundred nineteen patients had pure mitral regurgitation (31%), 275 had pure stenosis (38%), and 220 had mixed lesions (31%). However, 36 of 46 patients (78%) who had surgery in the first 10 years of life had pure mitral regurgitation; pure regurgitation was the most common lesion in patients 20 years of age and younger, accounting for 58% of surgically treated rheumatic mitral valve disease (158 of 271 cases) in this age group. Eighty-nine percent (194 of 219) of patients with pure mitral regurgitation were 30 years of age or younger (Figure 1). In contrast, the prevalence of mitral stenosis increased with age. Only 20% of patients with pure stenosis (55 of 275) were less than 20 years of age. Mixed mitral valve disease also increased in frequency until the fourth decade, after which its prevalence declined slightly. Figure 1. Time-course analysis (by decades) of the relative prevalence of pure mitral regurgitation, mixed mitral valve disease, and pure mitral stenosis. Hemodynamic Data Average values for mean left atrial pressure were similarly increased in all three groups (24 mm Hg for pure regurgitation and pure stenosis and 25 mm Hg for mixed disease). Pure mitral regurgitation was also characterized by a markedly raised left atrial V wave (46 18 mm Hg) and an average V wave:mean left atrial pressure ratio of 1.9:1, indicating severe hemodynamic compromise [10]. In addition, left ventricular end-diastolic pressure was elevated, whereas the end-diastolic gradient across the mitral valve was trivial. Pure mitral stenosis

Ultrasonic backscatter system for automated on-line endocardial boundary detection: Evaluation by ultrafast computed tomography

OBJECTIVES The purpose of this study was to evaluate the accuracy of the recently developed echocardiographic on-line endocardial border detection system using ultrafast computed tomography, an independent and proved tomographic imaging modality. BACKGROUND The automated system for on-line endocardial border detection identifies the blood-tissue interface by acoustic quantification of the ultrasonic backscatter signal. METHODS Eighteen subjects were screened by conventional echocardiography and acoustic quantification. Ten of these, with high quality echocardiographic images, were also examined by ultrafast computed tomography. Comparable image planes at the midpapillary level were analyzed. Measurements of left ventricular cavity area were compared at end-diastole and end-systole and time course analyses of cavity area during the cardiac cycle were performed. RESULTS There was good correlation between values for left ventricular end-diastolic area (r = 0.99), end-systolic area (r = 0.93) and fractional area change (r = 0.91) using the two methods. The on-line backscatter system underestimated end-diastolic area (p < 0.001), but the negative bias was small (-1.6 cm2) and the 95% confidence intervals were narrow (-3.6 cm2 to +0.4 cm2). In contrast, the backscatter system overestimated end-systolic area (p < 0.02); the positive bias for this variable was also small (+2.6 cm2) but the confidence intervals were relatively wide (+7.9 to -2.8 cm2). The negative bias of backscatter values for cavity area was fairly constant during diastole and early systole (range -5% to -10%), but during the second half of systole, backscatter values increased progressively relative to computed tomographic values. Real time values for fractional area change measured by the backscatter system were 13% smaller than those determined by ultrafast computed tomography (p < 0.001), with wide confidence intervals (+3% to -30%). Absolute peak rates of area change during systole and diastole were lower by 39% (p < 0.001) and 41% (p < 0.01), respectively, using the on-line ultrasonic backscatter system. Time course analyses revealed the errors to be consistent with cardiac cycle-dependent alterations in gain sensitivity of the ultrasonic backscatter system. CONCLUSIONS The ultrasonic backscatter system is associated with cyclic cavity area measurement errors that need to be addressed if its early promise for on-line assessment of ventricular function is to be fulfilled. Incorporation of an electrocardiographically triggered time-varying gain control may improve accuracy for on-line analysis of ventricular performance.

Noninvasive method for determination of arterial compliance using Doppler echocardiography and subclavian pulse tracings. Validation and clinical application of a physiological model of the circulation.

BACKGROUND The Poiseuillian model of the arterial system currently applied in clinical physiology does not explain how arterial pressure is maintained during diastole after cessation of pulsatile aortic inflow. Arterial pressure-flow relations can be more accurately described by models that incorporate arterial viscoelastic properties such as arterial compliance. Continuous pressure and flow measurements are needed to evaluate these properties. Since the techniques used to date to acquire such data have been invasive, physiological models of the circulation that incorporate these properties have not been widely applied in the clinical setting. The purpose of this study was (1) to validate noninvasive methods for continuous measurement of central arterial pressure and flow and (2) to determine normal reference values for arterial compliance using physiological models of the circulation applied to the noninvasively acquired pressure and flow data. METHODS AND RESULTS Simultaneously acquired invasive and noninvasive aortic pressures (30 patients), flows (8 patients), and arterial mechanical properties (8 patients) were compared. Pressure was measured by high-fidelity catheter aortic micromanometer (invasive) and calibrated subclavian pulse tracing (noninvasive). Aortic inflow was determined from thermodilution-calibrated electromagnetic flow velocity data (invasive) and echo-Doppler data (noninvasive). Arterial compliance was determined for two- and three-element windkessel models of the circulation using the area method and an iterative procedure, respectively. Once validated, the noninvasive methodology was used to determine normal compliance values for a reference population of 70 subjects (age range, 20 to 81 years) with normal 24-hour ambulatory blood pressures and without Doppler-echocardiographic evidence for structural heart disease. The limits of agreement between invasive and noninvasive pressure data, compared at 10% intervals during ejection and nonejection, were narrow over a wide range of pressures, with no significant differences between methods. Invasive and noninvasive instantaneous aortic inflow values differed slightly but significantly at the start of ejection (P < .05), but during the latter 90% of ejection, values for the two methods were similar, with narrow limits of agreement. Total vascular resistance and arterial compliance values derived from invasive and noninvasive data were similar. Arterial compliance values for the normal population using the two-element model (C2E) ranged from 0.74 to 2.44 cm3/mm Hg (mean, 1.57 +/- 0.38 cm3/mm Hg), with a beat-to-beat variability of 5.2 +/- 3.9%. C2E decreased with increasing age (r = -.73, P < .001) and tended to be higher in men (1.67 +/- 0.41 cm3/mm Hg) than in women (1.51 +/- 0.35 cm3/mm Hg, P = .07). Compliance values for the three-element model (C3E) were predictably smaller than for the two-element model (mean, 1.23 +/- 0.30; range, 0.59 to 2.16 cm3/mm Hg, P < .001 versus C2E) but correlated with C2E values (r = .81, P < .001) and were also inversely related to age (r = -.56, P < .001). Ridge regression and principal component analyses both showed the compliance value to be a composite function whose variation could be best predicted by consideration of simultaneous values for five major hemodynamic determinants: heart rate, mean flow, mean aortic pressure, minimal diastolic pressure, and end-systolic pressure. Multivariate analysis revealed age and sex to be independent predictors of compliance (P < .01 for both). There were no differences in compliance between black and white subjects. CONCLUSIONS Noninvasive methods can be used to acquire the hemodynamic data necessary for clinical application of physiological models of the circulation that incorporate arterial viscoelastic properties such as arterial compliance. The strong inverse linear relation between model-based compliance estimates and age mandates incorporation of this demographic parameter in

Effects of simultaneous alterations in preload and afterload on measurements of left ventricular contractility in patients with dilated cardiomyopathy: comparisons of ejection phase, isovolumetric and end-systolic force-velocity indexes.

OBJECTIVES The study was designed to critically evaluate the clinical utility of ejection phase and nonejection phase indexes of contractile state in patients with severe left ventricular dysfunction. BACKGROUND Ejection phase indexes of left ventricular systolic performance are unable to differentiate contractility changes from alterations in loading conditions. Isovolumetric and end-systolic force-velocity indexes have been proposed as alternative measurements of contractile state that are load independent. METHODS Seventeen patients with nonischemic dilated cardiomyopathy were studied during cardiac catheterization. High fidelity central aortic and left ventricular pressure measurements were made with simultaneous echocardiographic recordings of chamber minor- and long-axis dimensions and wall thickness. Data were acquired under control conditions, during nitroprusside infusion and with dopamine (6 micrograms/kg per min). RESULTS Patients were classified into those without (group 1, n = 10) and those with (group 2, n = 7) a decrease in end-diastolic circumferential wall stress in response to dopamine. There were no baseline differences between the groups in functional class, left ventricular chamber geometry or cardiovascular hemodynamics. Ejection phase indexes were variably altered by changes in preload, afterload and heart rate, thereby complicating physiologic interpretation of data. Dopamine increased the commonly used isovolumetric index, maximal rate of rise in left ventricular pressure (dP/dtmax), by 64% for group 1 but by only 16% for group 2 (p less than 0.001), resulting in an underestimation of contractile state change in 41% of patients. In contrast, the left ventricular end-systolic circumferential wall stress-rate-corrected velocity of fiber shortening relation, which incorporates afterload, ventricular wall mass and heart rate in its analysis, was a sensitive contractility measurement that was preload independent and equally augmented by dopamine for both groups. CONCLUSIONS Of the left ventricular contractility indexes evaluated, the end-systolic circumferential wall stress-rate-corrected velocity of fiber shortening relation was the most physiologically appropriate for assessing pharmacologically induced changes in inotropic state that were accompanied by complex alterations in loading conditions in patients with dilated cardiomyopathy.

Comparison of estimates of right atrial pressure by physical examination and echocardiography in patients with congestive heart failure and reasons for discrepancies

Clinical estimates of right atrial pressure from the jugular venous pulse were accurate when right atrial pressure was normal, but systematically underestimated elevated right atrial pressures. Because the increased distance from the mid-right atrium to the sternal angle is not accounted for, apparently normal right atrial pressure estimates by this technique do not reliably exclude elevated right atrial pressure in patients with congestive heart failure.

Differential Effects of Chronic Oral Antihypertensive Therapies on Systemic Arterial Circulation and Ventricular Energetics in African-American Patients

BACKGROUND A comprehensive evaluation of arterial load characteristics and left ventricular energetics in systemic hypertension has been limited by the need for invasive techniques to access instantaneous aortic pressure and flow. As a consequence of this methodological limitation, no data exist on the effects of long-term antihypertensive therapy on global arterial impedance properties and indexes of myocardial oxygen consumption (MVO2). Using recently validated noninvasive techniques, we compared in hypertensive patients the effects of chronic oral treatment with ramipril, nifedipine, and atenolol on arterial impedance and mechanical power dissipation as well as indexes of MVO2. METHODS AND RESULTS Sixteen African-American subjects with systemic hypertension were studied with a randomized, double-blind, crossover protocol. Instantaneous central aortic pressure and flow, from which arterial load characteristics can be derived, were estimated from calibrated subclavian pulse tracings (SPTs) and continuous-wave aortic Doppler velocity in conjunction with two-dimensional (2D) echocardiographic measurements of the aortic annulus, respectively. To derive ventricular wall stress and indexes of MVO2, left ventricular short- (M-mode) and long-axis (2D echo) images were acquired simultaneously with SPTs. Data were collected at the end of a 2-week washout period (predrug control) and after 6 weeks of treatment with each agent. Although all three agents reduced diastolic blood pressure to the same extent, different effects on mean and systolic pressures and vascular impedance properties were noted. Nifedipine reduced total peripheral resistance (TPR; 1744 +/- 398 versus 1290 +/- 215 dyne-s/cm5) and increased arterial compliance (ACL; 1.234 +/- 0.253 versus 1.776 +/- 0.415 mL/mm Hg). This improvement in arterial compliance was not entirely accounted for by the reduction in distending pressure. Ramipril also decreased TPR (1740 +/- 292 versus 1437 +/- 290 dyne-s/cm5) and increased ACL (1.214 +/- 0.190 versus 1.569 +/- 0.424 mL/mm Hg), but with this agent, the change in arterial compliance was explained solely on the basis of a reduction in distending pressure. Atenolol, in contrast, did not affect either TPR or ACL. In agreement with the compliance results, nifedipine and ramipril significantly lowered the first two harmonics of the impedance spectrum, but atenolol did not. None of these agents resulted in a significant change in characteristic impedance or in the relative amplitude of the reflected pressure wave. Total vascular mechanical power and percent of oscillatory power remained unaltered with all antihypertensive treatments. Only ramipril and nifedipine reduced the integral of both meridional and circumferential systolic wall stresses, indicating that MVO2 per beat was reduced with these agents. Stress-time index, a measure of MVO2 per unit time, decreased significantly with ramipril but not with nifedipine because of an increase in heart rate noted in 10 of 16 patients (mean increase, 10 beats per minute). Thus, a reduction in MVO2 coupled with unchanged total vascular mechanical power suggests improved efficiency of ventriculoarterial coupling with ramipril and with nifedipine in the subset of patients in whom heart rate remained unchanged. In contrast, there was no evidence of a reduction in wall stress, stress integral, or stress-time index with atenolol. CONCLUSIONS The noninvasive methodology used in this study constitutes a new tool for serial and simultaneous evaluation of arterial hemodynamics and left ventricular energetics in systemic hypertension. In this study, we demonstrate the differential effects of chronic antihypertensive therapies on systemic arterial circulation and indexes of MVO2 in African-American subjects. Consideration of drug-induced differential responses of arterial load and indexes of MVO2 with each drug may provide a more physiological approach to the treatment of systemic hypertension in indivi

Assessment of Small-Diameter Aortic Mechanical Prostheses Physiological Relevance of the Doppler Gradient, Utility of Flow Augmentation, and Limitations of Orifice Area Estimation

BACKGROUND Noninvasive assessment of functionally stenotic small-diameter aortic mechanical prostheses is complicated by theoretical constraints relating to the hemodynamic relevance of Doppler-derived transprosthetic gradients. To establish the utility of Doppler echocardiography for evaluation of these valves, 20-mm Medtronic Hall and 19-mm St Jude prostheses were studied in vitro and in vivo. METHODS AND RESULTS Relations between the orifice transprosthetic gradient (equivalent to Doppler), the downstream gradient in the zone of recovered pressure (equivalent to catheter), and fluid mechanical energy losses were examined in vitro. Pressure-flow relations across the 2 prostheses were evaluated by Doppler echocardiography in vivo. For both types of prosthesis in vitro, the orifice was higher than the downstream gradient (P<0.001), and fluid mechanical energy losses were as strongly correlated with orifice as with downstream pressure gradients (r2=0.99 for both). Orifice and downstream gradients were higher and fluid mechanical energy losses were larger for the St Jude than the Medtronic Hall valve (all P<0.001). Whereas estimated effective orifice areas for the 2 valves in vivo were not significantly different, model-independent dynamic analysis of pressure-flow relations revealed higher gradients for the St Jude than the Medtronic Hall valve at a given flow rate (P<0.05). CONCLUSIONS Even in the presence of significant pressure recovery, the Doppler-derived gradient across small-diameter aortic mechanical prostheses does have hemodynamic relevance insofar as it reflects myocardial energy expenditure. Small differences in function between stenotic aortic mechanical prostheses, undetectable by conventional orifice area estimations, can be identified by dynamic Doppler echocardiographic analysis of pressure-flow relations.

Effects of left ventricular pressure on sonicated albumin microbubbles : evaluation using an isolated rabbit heart model

OBJECTIVES We used an isolated, crystalloid-perfused rabbit heart model to test the hypothesis that the phasic changes in left ventricular contrast are due to bubble compression and decompression during systole and diastole, respectively. BACKGROUND Contrast enhancement of the left ventricular cavity has been shown to decrease during ventricular systole. This phenomenon has been attributed to pressure-induced microbubble destruction. Such destruction, if confirmed, would severely confound the quantitative interpretation of contrast echocardiographic data. METHODS A fixed volume of contrast solution (5% human albumin and Albunex, approximately 400:1 ratio) was introduced into a latex balloon placed within the left ventricular cavity of an isolated paced rabbit heart preparation (n = 12). Instantaneous left ventricular pressure was measured using a high fidelity microtip catheter and digitized on-line. The beating heart was placed in a water tank, and ultrasound images were obtained using a 7.5-MHz transducer and were recorded and digitized off-line at 12 frames/s. Simultaneously, the pacing signal was used for gated on-line acquisition of end-diastolic frames. A simple theoretic model based on surface tension physical principles was used to predict changes in bubble size and, consequently, the reflection intensity in response to the measured changes in left ventricular pressure. RESULTS We found that under peak left ventricular systolic pressures ranging from 89 to 155 mm Hg, 1) end-diastolic videointensity decreased by 8 +/- 6% (mean +/- SD) over 25 consecutive heart beats; and 2) intracyclic variations in measured videointensity were in close agreement with the theoretic calculations: 80.1 +/- 2.9% versus 80.2 +/- 4.6% of diastolic videointensity at systole. CONCLUSIONS The major cause of systolic decrease in contrast enhancement is periodic bubble compression (as opposed to bubble destruction) induced by high systolic pressures. The minor progressive decrease in end-diastolic videointensity reflects the degree of instability of Albunex microbubbles under left ventricular pressures. However, the clinical impact of these destructive effects is likely to be only minor because of the rapid transit of microbubbles through the left heart chambers and myocardial microcirculation.

Comparison of doppler indexes of left ventricular diastolic function with simultaneous high fidelity left atrial and ventricular pressures in idiopathic dilated cardiomyopathy

Doppler echocardiographic indexes of ventricular inflow have been used clinically to characterize left ventricular (LV) diastolic function. The reliability of these indexes as markers for intrinsic myocardial diastolic properties has been questioned. Micro-manometer left atrial (LA) and LV pressures as well as transmitral Doppler flow velocity signals and M-mode and 2-dimensional echocardiograms were simultaneously recorded. These unique measurements were acquired in patients with dilated cardiomyopathy under baseline conditions and during infusion of high dose amrinone. The response to amrinone was chosen as a hemodynamic model because this drug has previously been described as having beneficial effects on overall LV systolic and diastolic performance. At peak amrinone effect, LV contractility increased (as assessed using load independent end-systolic indexes) and early diastolic relaxation improved whereas passive chamber stiffness, heart rate and stroke volume were unchanged. There was a significant decrease in LV end-diastolic pressure as well as a parallel downward shift of the entire LV diastolic pressure-dimension relation. These findings, which indicated an improvement in overall LV diastolic properties, probably represent the combination of more rapid early diastolic relaxation in conjunction with a reduction in venous return, the relief of pericardial restraint or the reduction in right ventricular-LV interaction. In contrast, the ratios of Doppler-determined peak transmitral early-to-late flow velocities and early-to-late diastolic flow velocity integrals decreased with amrinone infusion, thereby suggesting a drug-induced decrease in LV diastolic compliance. Thus, in patients with idiopathic dilated cardiomyopathy, administration of amrinone has a complex effect on LV diastolic properties.(ABSTRACT TRUNCATED AT 250 WORDS)

Double-chambered Left Ventricle: Submitral Accessory Valvular Tissue Causing Inlet and Outlet Obstruction

We report a patient with a large submitral ridge of muscular and fibrous tissue that divides the left ventricle into two distinct chambers causing inlet and outlet obstruction. Doppler echocardiography revealed obstruction to both filling and ejection. Echocardiography demonstrated that the obstruction was in series with the mitral apparatus. Surgery was done with resection of much of this ring of tissue. Subsequent studies revealed morphologic and hemodynamic improvement.