William H. Gaasch

Guidelines for the Management of Patients With Valvular Heart Disease Executive Summary A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on Management of Patients With Valvular Heart Disease)

This executive summary and recommendations appears in the November 3, 1998, issue of Circulation . The guidelines in their entirety, including the ACC/AHA Class I, II, and III recommendations, are published in the November 1, 1998, issue of the Journal of the American College of Cardiology . Reprints of both the full text and the executive summary and recommendations are available from both organizations. During the past 2 decades, major advances have occurred in diagnostic techniques, the understanding of natural history, and interventional cardiological and surgical procedures for patients with valvular heart disease. The information base from which to make clinical management decisions has greatly expanded in recent years, yet in many situations, management issues remain controversial or uncertain. Unlike many other forms of cardiovascular disease, there is a scarcity of large-scale multicenter trials addressing the diagnosis and treatment of valvular disease from which to derive definitive conclusions, and the literature represents primarily the experiences reported by single institutions in relatively small numbers of patients. The Committee on Management of Patients With Valvular Disease was given the task of reviewing and compiling this information base and making recommendations for diagnostic testing, treatment, and physical activity. These guidelines follow the format established in previous American College of Cardiology/American Heart Association (ACC/AHA) guidelines for classifying indications for diagnostic and therapeutic procedures: Class I: Conditions for which there is evidence and/or general agreement that a given procedure or treatment is useful and effective Class II: Conditions for which there is conflicting evidence and/or a divergence of opinion about the usefulness/efficacy of a procedure or treatment IIa. Weight of evidence/opinion is in favor of usefulness/efficacy IIb. Usefulness/efficacy is less well established by evidence/opinion. Class III: Conditions for which there is evidence and/or general agreement that the procedure/treatment is not useful and in some cases …

Left ventricular compliance: Mechanisms and clinical implications

Left ventricular diastolic compliance is determined by the level of operating pressure and the diastolic pressure-volume relation. This relation is curvillinear and the slope of a tangent (operative chamber stiffness) to the pressure-volume curve increases as the chamber progressively fills. Such preload-dependent changes in compliance occur during any acute alteration in ventricular volume. At a given diastolic pressure, operative chamber stiffness (or its reciprocal, operative chamber compliance) is determined by the relative values for ventricular volume and muscle mass and by the stiffness of a unit of myocardium. Thus, there may be a leftward shift of the diastolic pressure-volume curve (increase in the modulus of chamber stiffness) as a consequence of ventricular hypertrophy or an increase in the stiffness of heart muscle itself (increase in modulus of muscle stiffness). To distinguish between hypertrophy and stiff muscle, it is useful to examine the modulus of chamber stiffness, derived from pressure-volume data, together with the volume/mass ratio of the ventricle. In this fashion, changes in the modulus of chamber stiffness that are inappropriate for a given volume/mass ratio may be attributed to changes in the material properties of the heart muscle. Examples of clinical and experimental pressure-volume studies are presented to illustrate the variety of mechanisms by which acute and chronic changes in ventricular chamber compliance evolve during the course of clinical heart disease. The pathophysiology of pulmonary congestion is best understood by considering the factors responsible for producing changes in chamber stiffness of the ventricle, whereas an examination of muscle stiffness is likely to provide more insight into the extent of irreversible functional and structural defects of the myocardium.

Geometric changes allow normal ejection fraction despite depressed myocardial shortening in hypertensive left ventricular hypertrophy

OBJECTIVES This study of hypertensive left ventricular hypertrophy 1) assessed myocardial shortening in both the circumferential and long-axis planes, and 2) investigated the relation between geometry and systolic function. BACKGROUND In hypertensive left ventricular hypertrophy, whole-heart studies have suggested normal systolic function on the basis of ejection fraction-systolic stress relations. By contrast, isolated muscle data show that contractility is depressed. It occurred to use that this discrepancy could be related to geometric factors (relative wall thickness). METHODS We studied 43 patients with hypertensive left ventricular hypertrophy and normal ejection fraction (mean +/- SD 69 +/- 13%) and 50 clinically normal subjects. By echocardiography, percent myocardial shortening was measured in two orthogonal planes; circumferential shortening was measured at the endocardium and at the midwall, and long-axis shortening was derived from mitral annular motion (apical four-chamber view). Circumferential shortening was related to end-systolic circumferential stress and long-axis shortening to meridional stress. RESULTS Endocardial circumferential shortening was higher than normal (42 +/- 10% vs. 37 +/- 5%, p < 0.01) and midwall circumferential shortening lower than normal in the left ventricular hypertrophy group (18 +/- 3% vs. 21 +/- 3%, p < 0.01). Differences between endocardial and midwall circumferential shortening are directly related to differences in relative wall thickness. Long-axis shortening was also depressed in the left ventricular hypertrophy group (18 +/- 6% in the left ventricular hypertrophy group, 21 +/- 5% in control subjects, p < 0.05). Midwall circumferential shortening and end-systolic circumferential stress relations in the normal group showed the expected inverse relation; those for approximately 33% of the left ventricular hypertrophy group were > 2 SD of normal relations, indicating depressed myocardial function. There was no significant relation between long-axis shortening and meridional stress, indicating that factors other than afterload influence shortening in this plane. CONCLUSIONS High relative wall thickness allows preserved ejection fraction and normal circumferential shortening at the endocardium despite depressed myocardial shortening in two orthogonal planes.

Left ventricular midwall mechanics in systemic arterial hypertension. Myocardial function is depressed in pressure-overload hypertrophy.

BackgroundLeft ventricular (LV) midwall geometry has been described conventionally as the sum of the chamber radius and half of the wall thickness; this convention is based on the assumption of uniform transmural thickening during systole. However, theoretical considerations and experimental data indicate that the inner half (inner shell) of the LV wall thickens more than the outer half (outer shell). Thus, an end-diastolic circumferential midwall fiber exhibits a relative migration toward the epicardium during systole. As a result, the conventional method provides an overestimate of the extent of the midwall fiber shortening. Methods and ResultsWe developed an ellipsoidal model with a concentric two-shell geometry (nonuniform thickening) to assess midwall fiber length transients throughout the cardiac cycle. This modified midwall method was used in the analysis of LV cineangiograms from 15 patients with systemic arterial hypertension and 14 normal subjects. Study groups were classified according to LV mass index (LVMI): 14 normal subjects (group I), eight hypertensive patients with a normal LVMI (group II), and seven hypertensive patients with an increased LVMI (group III). There were no significant differences in LV end-diastolic pressure or volume among the three groups; the ejection fraction was slightly greater in group 11 (70 + 5%) than in groups I (65±8%) and III (664±4%), but this trend did not achieve statistical significance. Values for endocardial and conventional midwall fractional shortening (FS) were also similar in the three groups. By contrast, FS by the concentric two-shell geometry (modified midwall method) in group III (16±2%) was significantly less than that seen in groups I and II (21±4% and 21 + 5%, respectively; both p < 0.05). This difference achieves greater importance when it is recognized that mean systolic circumferential stress was lower in group III (151±22 g/cm2) than in groups I and 11 (244±37 g/cm2 and 213+38 g/cm2, respectively; both p<0.01). The midwall stressshortening coordinates in six of the seven group III patients were outside the 95% confidence limits for the normal (group I) subjects. Thus, despite a normal ejection fraction, systolic function is subnormal in hypertensive patients with LV hypertrophy. ConclusionsChamber dynamics provide an overestimate of myocardial function, especially when LV wall thickness is increased. This is due to a relatively greater contribution of inner shell thickening in pressure-overload hypertrophy.

Left Ventricular Systolic Performance, Function, and Contractility in Patients With Diastolic Heart Failure

Background—Patients with diastolic heart failure (DHF) have significant abnormalities in left ventricular (LV) diastolic function, including slow and delayed relaxation and increased chamber stiffness. Whether and to what extent these abnormalities in diastolic function occur in association with abnormalities in LV systolic performance, function, and contractility has not been investigated thoroughly. Methods and Results—The systolic properties of the LV were examined in 75 patients with heart failure and a normal ejection fraction (ie, DHF) and 75 normal control subjects with no evidence of cardiovascular disease. LV systolic properties were assessed with echocardiographic and cardiac catheterization data. Stroke work (an index of LV systolic performance), preload recruitable stroke work and ejection fraction (indices of LV systolic function), systolic stress-shortening relationship, end-systolic pressure-volume relationship, and peak (+)dP/dt (indices of LV contractility) were examined. The systolic properties of the LV were normal in patients with DHF. Stroke work was 8.4±2.3 in DHF versus 8.8±2.5 kg · cm in controls (P=0.26). Preload recruitable stroke work was 99±22 in DHF versus 109±18 g/cm2 in controls (P=0.13). The relationship between stroke work and end-diastolic volume was similar in DHF and controls. Peak (+) dP/dt was 1596±362 in DHF versus 1664±305 mm Hg/s in controls (P=0.54). The end-systolic pressure-volume relationship was increased in DHF. The systolic stress versus endocardial fractional shortening relationship was similar in DHF and controls. Conclusions—Patients with DHF had normal LV systolic performance, function, and contractility. The pathophysiology of DHF does not appear to be related to significant abnormalities in these systolic properties of the LV.

Left ventricular radius to wall thickness ratio

Left ventricular relative wall thickness, expressed as the ratio of end-diastolic radius to wall thickness (R/Th ratio), has a constant relation with left ventricular systolic pressure in children and adults with a normal heart, subjects with physiologic forms of cardiac hypertrophy (athletes) and patients with compensated chronic left ventricular volume overload (chronic aortic regurgitation). Greatly increased values for the radius/thickness ratio, suggesting inadequate hypertrophy, indicate a poor prognosis in patients with chronic aortic regurgitation and in those with congestive cardiomyopathy; decreased values for this ratio are found in patients with hypertrophic cardiomyopathy (inappropriate hypertrophy) and in patients with compensated aortic stenosis (appropriate hypertrophy). In patients with compensated aortic stenosis, echocardiographic measurement of the left ventricular end-diastolic radius/wall thickness ratio has been used to estimate left ventricular systolic pressure. Measurement of left ventricular relative wall thickness appears to provide diagnostic and prognostic data in patients with a broad variety of cardiac disorders.

Left Ventricular Stress and Compliance in Man With Special Reference to Normalized Ventricular Function Curves

Left ventricular circumferential end-diastolic stress (Sed), peak systolic stress (Sps), and compliance at end-diastole ([dV/VdP]ed) were estimated in 13 subjects with normal left ventricles (N group), nine subjects with inappropriate hypertrophy (IH group), five with aortic valvular stenosis (AS group), and six with congestive cardiomyopathy (CC group). The product of Sed and (dV/dP)ed was employed as an index of “muscle fiber stretch” and related to systolic indices of ventricular performance. Compliance was significantly less than normal in IH (P < 0.001), in AS (P < 0.01), and in CC (P < 0.001), while end-diastolic volumes were smaller than normal (P < 0.05), normal (P = NS), and larger than normal (P < 0.001) in the three groups, respectively. Sed was normal in IH and AS but elevated in CC (P < 0.001), while Sps was decreased in IH and normal in AS and CC. “Muscle fiber stretch,” however, was substantially less than normal in IH (P < 0.001), indicating that the low Sps is due at least in part to short sarcomeres. In CC, despite a markedly elevated preload, “muscle fiber stretch” was normal (P = NS), while work indices of the ventricle were diminished indicating depressed ventricular function. Thus, the product of Sed and (dV/VdP) ed provides a normalized index of “muscle fiber stretch,” which permits one to compare length-tension or length-work relationships in diseased ventricles of varying dimensions and compliance.

Stress-shortening relations and myocardial blood flow in compensated and failing canine hearts with pressure-overload hypertrophy.

Serial changes in left ventricular (LV) size and function during the adaptation to chronic pressure overload and the transition to pump failure were studied in 16 conscious dogs (aortic bands placed at 8 weeks of age). Echocardiographic data at baseline and at 3, 6, 9, and 12 months after banding revealed a progressive increase in LV mass in all dogs. In six dogs with LV pump failure, there was a progressive decline in circumferential fiber shortening (29 +/- 4% at 12 months); this was significantly less than that seen in five littermate controls (38 +/- 3%, p less than 0.05). The average LV to body weight ratio in this group was 9.8 +/- 2.7 g/kg. In 10 dogs without pump failure (compensated LVH group), shortening exceeded that seen in the controls (43 +/- 4%, p less than 0.05); the LV to body weight ratio was 7.7 +/- 1.0 g/kg. At 12 months (cardiac catheterization), the LV end-diastolic pressure was higher in the failure (25 +/- 15 mm Hg) than in the compensated group (8 +/- 5 mm Hg, p less than 0.05); mean systolic stress was also higher in the failure group (313 +/- 67 g/cm2) than in the compensated group (202 +/- 53 g/cm2, p less than 0.05). The transmural distribution of myocardial blood flow was measured (at 12 months) with the radioactive microsphere technique; flow data were then related to an index of demand (a stress-time index). There was preferential blood flow to the subendocardial layers in the control (endo/epi = 1.28) and compensated hearts (endo/epi = 1.10), but in the failure group there was a relative decrease in subendocardial flow (endo/epi = 0.92). However, the absolute values for subendocardial flow in the normal, compensated, and failure groups were 77 +/- 54, 125 +/- 48, and 113 +/- 64 ml/min/100 g; the stress-time indexes in the subendocardial shell were 38 +/- 11, 74 +/- 19, and 93 +/- 34 g sec.10(2)/cm2/min. Despite what appears to be a marginal balance between blood flow and the stress time index in the failure group, the myocardial high energy phosphates were not depleted and the inoptropic state was not depressed. In this model of LV hypertrophy, the observed differences in fiber shortening can be explained on the basis of the inverse afterload-shortening relation; pump failure was due to an inadequate LV hypertrophy with afterload excess.(ABSTRACT TRUNCATED AT 400 WORDS)

Mode of Death in Patients With Heart Failure and a Preserved Ejection Fraction Results From the Irbesartan in Heart Failure With Preserved Ejection Fraction Study (I-Preserve) Trial

Background— The mode of death has been well characterized in patients with heart failure and a reduced ejection fraction; however, less is known about the mode of death in patients with heart failure and a preserved ejection fraction (HFPEF). The purpose of this study was to examine the mode of death in patients with HFPEF enrolled in the Irbesartan in Heart Failure With Preserved Ejection Fraction Study (I-Preserve) trial and to determine whether irbesartan altered the distribution of mode of death in HFPEF. Methods and Results— All deaths were reviewed by a clinical end-point committee, and the mode of death was assigned by consensus of the members. The annual mortality rate was 5.2% in the I-Preserve trial. There were no significant differences in mortality rate between the placebo and irbesartan groups. The mode of death was cardiovascular in 60% (including 26% sudden, 14% heart failure, 5% myocardial infarction, and 9% stroke), noncardiovascular in 30%, and unknown in 10%. There were no differences in the distribution of mode-specific mortality rates between placebo and irbesartan. Conclusions— Sixty percent of the deaths in patients with HFPEF were cardiovascular, with sudden death and heart failure death being the most common. Treatment with irbesartan did not affect overall mortality or the distribution of mode-specific mortality rates. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00095238.

Contractile Behavior of the Left Ventricle in Diastolic Heart Failure With Emphasis on Regional Systolic Function

Received March 31, 2005; revision received July 15, 2005; accepted July 21, 2005. In diastolic heart failure, the left ventricular (LV) ejection fraction (EF) is normal and there is increased passive stiffness with impaired relaxation of the ventricle, resulting in disturbances in the pattern of filling and elevated diastolic pressure.1–3 The mechanism underlying such failure has been thought to be principally diastolic because LV diastolic function is universally abnormal and systolic performance, function, and contractility are normal.4 However, several reports suggest that abnormalities in regional shortening are present in diastolic heart failure.5–9 The significance of these findings, especially their relation to the syndrome of heart failure, remains uncertain. Accordingly, we will review some of the structural and functional differences between systolic and diastolic heart failure, and, emphasizing the systolic or contractile behavior of the left ventricle, we will attempt to reconcile what appear to be disparate conclusions about LV systolic function in patients with diastolic heart failure. The hearts of patients with systolic heart failure differ dramatically from those of patients with diastolic heart failure in regard to both gross and microscopic anatomic features. As will be seen, these anatomic differences tend to parallel physiological and functional differences in systolic and diastolic heart failure10,11 (Table 1). View this table: TABLE 1. LV Structure and Function in Chronic Heart Failure ### LV Chamber Remodeling Patients with diastolic heart failure generally exhibit a concentric pattern of LV remodeling and a hypertrophic process that is characterized by a normal or near-normal end-diastolic volume, increased wall thickness, and a high ratio of mass to volume with a high ratio of wall thickness to chamber radius.12 By contrast, patients with systolic heart failure exhibit a pattern of eccentric remodeling with an increase in end-diastolic volume, little increase in wall thickness, and a substantial decrease in the ratio …