Atrial systole and left ventricular filling in hypertrophic cardiomyopathy: effect of verapamil

Diastolic measurements from alternate R-wave gating of radionuclide angiograms

Left ventricular diastolic filling measurements were determined by means of standard consecutive R-wave gating, list mode acquisition, and alternate R-wave gating. Time-activity curves obtained by the latter two methods were equally accurate in quantifying rapid, slow, and atrial left ventricular filling, whereas curves obtained by means of standard gating were inadequate for this purpose.

Effect of postural changes, nitroglycerin and verapamil on diastolic ventricular function as determined by radionuclide angiography in normal subjects

Whereas improvement in diastolic function indexes in response to therapeutic interventions has been attributed to a beneficial effect of the intervention, measurements of diastolic function appear to be influenced by changes in loading conditions, heart rate and sympathetic tone. To determine the effect of body position and short-term pharmacologic intervention on radionuclide angiographically determined left ventricular peak filling rate, high temporal resolution time-activity curves and absolute left ventricular volumes obtained by equilibrium-gated blood pool scans were evaluated in 12 normal subjects in the supine position at rest and in response to several postural and pharmacologic manipulations. This study confirmed the reproducibility of the technique and demonstrated that in normal subjects, peak filling rate varies in response to changes in body position and to short-term administration of sublingual nitroglycerin and intravenous verapamil. Peak filling rate ranged from 3.3 to 5.1 end-diastolic volumes (EDV)/s with a variability of 13.7% during five baseline supine measurements in the 12 subjects. Compared with values in the supine position (mean +/- SEM = 4.38 +/- 0.24 EDV/s), peak filling rate increased +16 +/- 6% to 4.75 +/- 0.27 EDV/s in the upright position (p less than 0.05) but did not change significantly with leg elevation. Peak filling rate at baseline and during postural changes correlated significantly with ejection fraction (r = +0.49), with stroke volume (r = +0.26) and inversely with end-systolic volume (r = -0.41), but did not correlate with heart rate or blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Patterns of diastolic dysfunction in left ventricular hypertrophy

The relative sensitivities of and interrelations between different measurements of diastolic function were studied in 50 patients with left ventricular hypertrophy diagnosed on anatomical grounds. Isovolumic relaxation time, the interval from minimum cavity dimension to mitral valve opening and relative dimension increase during this period, and the peak rate of dimension increase and wall thinning during rapid ventricular filling were measured by digitised M mode echocardiography. The relative heights of peak early diastolic and atrial velocities (a/E) and the time for decline of early diastolic velocity to half its peak value (velocity half time) were measured on continuous wave and pulsed Doppler and the relative height of the "a" wave was measured by apexcardiogram. All sets of values except those of the interval from minimum dimension to mitral opening were unimodally distributed, and all differed significantly from those in 20 age matched controls. The relative height of the "a" wave on the apexcardiogram (90% values were abnormal) was the most sensitive method of studying left ventricular diastolic function and peak rate of dimension increase was the least sensitive. Though none of the correlations was high, there were individual associations between peak rate of dimension increase, a/E, peak wall thinning rate, and velocity half time, and independently between delay in mitral valve opening and dimension change during this period. Other values seemed to be independent of one another, suggesting a different physiological basis. It is concluded that these various abnormal values do not reflect a single underlying disturbance of diastolic function. There are at least four possible discrete abnormalities: prolongation of isovolumic relaxation; incoordination during isovolumic relaxation; reduced rate of rapid filling; and an increase in the relative amplitude of the "a" wave probably caused by increased passive stiffness. These may be present singly or in combination in any patient.

Comparison of pulsed Doppler echocardiography and radionuclide angiography in the assessment of left ventricular filling

To determine the relation between Doppler echocardiographic and radionuclide angiographic indexes of left ventricular (LV) filling, 42 patients were studied using both techniques. From Doppler mitral flow velocity profiles, the percent of LV filling due to atrial systole (percent atrial contribution) and at one-third of diastole (one-third filling fraction), the peak filling rate and the peak filling rate normalized for LV end-diastolic volume and the time from mitral valve opening to peak early velocity and from aortic valve closure to peak early velocity were determined. Good correlations were found between percent atrial contribution (r = 0.83) and one-third filling fraction (r = 0.67) using the 2 techniques. However, Doppler normalized peak filling rate correlated only weakly with radionuclide peak filling rate (r = 0.33, p less than 0.05). There was no significant correlation between Doppler peak filling rate and radionuclide peak filling rate. Neither Doppler time from mitral valve opening to peak early velocity nor Doppler time from aortic closure to peak early velocity correlated with radionuclide time to peak filling rate. Thus, Doppler echocardiography and radionuclide angiography agree on relative diastolic filling indexes but not on peak filling rates or useful diastolic time intervals. Relative filling indexes, such as percent atrial contribution and one-third filling fractions, therefore, may be the most reliable noninvasive indicators of diastolic function.

Effects of verapamil on left ventricular diastolic filling in children with hypertrophic cardiomyopathy

The effects of oral verapamil on resting left ventricular (LV) diastolic filling were examined in 10 children and adolescents with hypertrophic cardiomyopathy. Measurements of diastolic filling were made from gated technetium-99m radionuclide angiograms with postbeat rejection of data outside a 5% RR-interval window. LV time-activity curves were generated and the rapid-filling phase fit with a 3 degrees polynomial to calculate the peak filling rate and the time from end-systole to the point of peak filling. All patients had a radionuclide angiogram performed before and after 0.25 to 3 years of oral verapamil therapy. Verapamil did not change the LV ejection fraction but increased the peak filling rate (3.24 +/- 0.15 to 4.62 +/- 1.05 end-diastolic volume/s,p less than 0.01) and reduced the time to peak filling (217 +/- 57 to 168 +/- 63 ms, p less than 0.01). An increase in exercise endurance as measured by exercise treadmill test and subjective symptomatic improvement were also seen after verapamil therapy. Thus, in children with hypertrophic cardiomyopathy, symptomatic improvement and LV diastolic filling parameters improved with long-term oral verapamil.

Myocardial perfusion abnormalities in patients with hypertrophic cardiomyopathy: assessment with thallium-201 emission computed tomography

Myocardial ischemia may play a critical role in the symptomatic presentation and natural history of hypertrophic cardiomyopathy (HCM). To assess the relative prevalence and functional significance of myocardial perfusion abnormalities in patients comprising the broad clinical spectrum of HCM, we studied 72 patients (ages 12 to 69 years, mean 40) using thallium-201 emission computed tomography. Imaging was performed immediately after maximal exercise and again after a 3 hr delay. Regional perfusion defects were identified in 41 of the 72 patients (57%). Fixed or only partially reversible defects were evident in 17 patients, 14 of whom (82%) had left ventricular ejection fractions of less than 50% at rest. Twenty-four patients demonstrated perfusion defects during exercise that completely reversed at rest; all had normal or hyperdynamic left ventricular systolic function (ejection fraction greater than or equal to 50%). Perfusion abnormalities were present in all regions of the left ventricle. However, the fixed defects were observed predominantly in segments of the left ventricular wall that were of normal or only mildly increased (15 to 20 mm) thickness; in contrast, a substantial proportion (41%) of the completely reversible defects occurred in areas of moderate-to-marked wall thickness (greater than or equal to 20 mm, p less than .001). Neither a history of chest pain nor its provocation with treadmill exercise was predictive of an abnormal thallium study, since regional perfusion defects were present in 10 of 18 (56%) completely asymptomatic patients, compared with 31 of 54 (58%) symptomatic patients. These data indicate that myocardial perfusion abnormalities occur commonly among patients with HCM. Fixed or only partially reversible defects suggestive of myocardial scar and/or severe ischemia occur primarily in patients with impaired systolic performance. Completely reversible perfusion abnormalities occur predominantly in patients with normal or supranormal left ventricular systolic function. Such dynamic changes in regional thallium activity may reflect an ischemic process that contributes importantly to the clinical manifestations and natural history of HCM.

Noninvasive assessment of left ventricular diastolic function by pulsed Doppler echocardiography in patients with hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy is a primary myocardial disease in which symptoms may frequently result from impaired left ventricular relaxation, filling and compliance. In the present investigation, Doppler echocardiography was utilized to measure transmitral flow velocity and thereby assess left ventricular diastolic performance noninvasively in a group of 111 patients representative of the broad clinical spectrum of hypertrophic cardiomyopathy. In patients with hypertrophic cardiomyopathy, all Doppler indexes of diastolic relaxation and filling differed significantly (p less than 0.001) from those obtained in 86 control subjects without heart disease, namely, prolongation of isovolumic relaxation (94 +/- 24 versus 78 +/- 12 ms) and of the early diastolic peak of flow velocity (244 +/- 55 versus 220 +/- 28 ms), as well as slower deceleration (3.4 +/- 1.4 versus 4.9 +/- 1.3 m/s2) and reduced maximal flow velocity in early diastole (0.5 +/- 0.2 versus 0.6 +/- 0.1 m/s). As an apparent compensation for impaired relaxation and early diastolic filling, the atrial contribution to left ventricular filling was increased, as shown by increased late diastolic flow velocity (0.4 +/- 0.3 versus 0.3 +/- 0.1 m/s) and reduced ratio of maximal flow velocity in early diastole to that in late diastole (1.4 +/- 0.8 versus 2.1 +/- 0.9). The vast majority of patients with hypertrophic cardiomyopathy (91 [82%] of 111) showed evidence of impaired left ventricular diastolic performance, as assessed from the Doppler waveform. Abnormal Doppler diastolic indexes were identified with similar frequency in patients with (78%) or without (83%) left ventricular outflow obstruction, as well as in patients with (84%) or without (80%) cardiac symptoms. However, patients with nonobstructive hypertrophic cardiomyopathy showed more severe alterations in the Doppler indexes of diastolic function than did patients with obstruction. Thus, abnormal diastolic performance as assessed by Doppler echocardiography was apparent in the vast majority of the study patients with hypertrophic cardiomyopathy, independent of the presence or absence of cardiac symptoms or a subaortic pressure gradient. The high frequency with which diastolic abnormalities are identified in asymptomatic patients with hypertrophic cardiomyopathy suggests that impaired diastolic performance may be present at a time in the natural history of the disease when functional limitation is not yet evident.

Hypertrophic cardiomyopathy: current views on etiology, pathophysiology, and management

Hypertrophic cardiomyopathy (HCM) is a primary myocardial disease of unknown cause that is characterized by a hypertrophied, nondilated, hypercontractile left ventricle. Its etiology and pathogenesis remain undefined but the three principal factors implicated are a genetic predisposition, a hypersensitivity to catecholamines, and an abnormal calcium metabolism. The hypertrophy typically involves the intraventricular septum to varying degrees, but may also involve the apex or free wall and even be concentric. The disease occurs in either an obstructive or a nonobstructive form depending on whether an intraventricular pressure gradient can be demonstrated at rest or on provocation. The gradient and obstruction to outflow is usually seen in patients with asymmetric septal hypertrophy (ASH) and anterior motion of the mitral valve during systole (SAM). Abnormal left ventricular diastolic function characterized by inadequate filling and impaired relaxation has been shown to be very important in both the obstructive and nonobstructive forms of the disease. In addition, inadequate coronary vasodilator reserve as a result of small vessel disease, microvascular spasm, and/or low capillary density per unit myocardial mass has been implicated as an important cause of ischemia in patients without coronary artery disease. HCM is a disease of young adulthood with relatively slow progression; young patients are often asymptomatic, whereas older patients are more limited by dyspnea, angina, dizziness, or syncope. Supraventricular tachyarrhythmias occur in 30% of patients, and high-grade ventricular arrhythmias occur in over 75%. The annual mortality is 3-5%. The common mode of demise is sudden cardiac death. Therefore, the primary objectives of treatment are the amelioration of symptoms, the control of arrhythmias, and the prevention of sudden death. Beta-adrenoreceptor blocking agents decrease myocardial contractility and oxygen demands and increase ventricular volume; therefore, they are most useful in patients with the obstructive form of HCM. Calcium channel antagonists enhance left ventricular relaxation, relieve microvascular spasm, and improve coronary filling and therefore are the agents of choice in patients with diastolic dysfunction. The ability of the calcium channel antagonists to decrease contractility makes them valuable in patients with obstructive HCM. Arterial vasodilators, diuretics, nitrates, and inotropic agents should be avoided because they can increase the intraventricular gradient. Myomyectomy is reserved for those patients with the obstructive form of HCM whose symptoms are refractory to medical therapy.(ABSTRACT TRUNCATED AT 400 WORDS)

Occurrence and significance of progressive left ventricular wall thinning and relative cavity dilatation in hypertrophic cardiomyopathy

This investigation was undertaken to assess the prevalence of systolic dysfunction, left ventricular (LV) wall thinning and cavity enlargement in a large population of patients with hypertrophic cardiomyopathy (HC), and to determine the role of these conditions in the natural history of this disease. Of 217 consecutively studied patients with HC, most of whom were severely symptomatic, 197 (91%) had an LV ejection fraction of 50% or more and 20 (9%) had an ejection fraction of less than 50% as assessed with radionuclide angiography. Changes in LV wall thickness and cavity dimension were evaluated using serial M-mode and 2-dimensional echocardiography over an average follow-up of 3.6 years in 67 of the 217 patients (54 with ejection fraction of greater than or equal to 50% and 13 with ejection fraction less than 50%). A substantial decrease (at least 5 mm) in LV wall thickness was seen in 8 of the 13 patients (62%) with an ejection fraction greater than or equal to 50%, but in only 2 of the 54 patients (4%) with an ejection fraction greater than or equal to 50% (p less than 0.001). LV cavity dimension increased significantly over the period of follow-up in the 13 patients with depressed ejection fraction (from 44 +/- 5 to 49 +/- 7 mm, p less than 0.005); however, absolute cavity size remained normal (less than or equal to 52 mm or less) in 10 of these 13 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial kinetics and left ventricular diastolic filling in the healthy elderly

A delay of left ventricular isovolumic relaxation and decrease in myocardial compliance may result in a decline of measured early filling rates in elderly subjects. Previous studies of diastolic function, however, have not excluded coronary artery disease or addressed the contribution of atrial contraction to diastole. The present study evaluated radionuclide-derived diastolic variables in 13 healthy elderly volunteers aged 75 +/- 6 years without symptoms or risk factors for coronary disease who had normal findings on the stress electrocardiogram, stress gated blood pool imaging and two-dimensional echocardiogram. Results were compared with those of a group of 10 healthy young volunteers aged 26 +/- 5 years. High count, 32 frame, double-buffered gated blood pool acquisitions were obtained at rest in the left anterior oblique view with an RR interval variation less than 5%. Left ventricular time-activity curves were analyzed and flow-volume loops for each group were constructed. In the healthy elderly: peak early diastolic filling rate is decreased, time of peak early filling and time to first third of diastolic filling are delayed, and peak late left ventricular filling rate and percent of atrial filling volume are augmented, suggesting an adaptive response of the atria to diminished left ventricular compliance.

Assessment of diastolic function in normal and hypertrophied hearts: comparison of Doppler echocardiography and M-mode echocardiography

Left ventricular (LV) filling was examined by Doppler and M-mode echocardiography in 24 patients with LV hypertrophy (five with aortic stenosis, six with hypertrophic cardiomyopathy, and 13 with LV hypertrophy secondary to systemic hypertension) and in 18 normal subjects. Patients with LV hypertrophy had significantly lower Doppler-determined peak filling rates (218 +/- 17 vs 288 +/- 66 cc/sec, p less than 0.01), but M-mode determined peak rate of chamber enlargement and normalized peak rate of chamber enlargement did not differ significantly between groups. Doppler measures of the ratio between early and late filling were significantly depressed in patients with LV hypertrophy and correlated inversely with age in the normal subjects. The M-mode derived normalized peak rate of chamber enlargement and the Doppler-derived normalized peak filling rate correlated weakly, but significantly, when both groups were combined (r = 0.56, p less than 0.01). Thus Doppler measurements can detect abnormalities of LV filling in patients with LV hypertrophy. These abnormalities are present when M-mode filling indices and systolic function are still normal.

Left ventricular diastolic function in hypertrophic cardiomyopathy: assessment by radionuclide angiography

Diastolic left ventricular function was studied in 20 patients with obstructive hypertrophic cardiomyopathy, 10 with apical hypertrophic cardiomyopathy, and 20 control subjects. The left ventricular time-activity curve was filtered using Fourier expansion with 4 harmonics. The first and second derivatives of the filtered curve were used to define various parameters of the left ventricle. Isovolumic relaxation period and time to peak filling rate were prolonged in obstructive hypertrophic cardiomyopathy and apical hypertrophic cardiomyopathy (101.56 +/- 44.81 msec, 105.19 +/- 45.27 versus 72.19 +/- 29.36 (CS) P less than 0.05; 169.70 +/- 50.73 msec, 173.83 +/- 50.53 versus 138.02 +/- 29.54 (CS) P less than 0.05, respectively). Rapid filling period, diastasis, atrial contraction period, time to peak filling rate-isovolumic relaxation period, and filling fraction of diastasis were not significantly different in these groups. Fasting filling fraction was 11% lower in hypertrophic groups than in control subjects. The filling fraction of atrial contribution was 12% higher in hypertrophic groups. We conclude: Isovolumic relaxation period, rapid filling phase, and diastasis atrial contraction period can be clearly defined by this technique. Impaired relaxation is an important determinant of decreased left ventricular filling in patients with obstructive hypertrophic cardiomyopathy and apical hypertrophic cardiomyopathy. Prolonged time to peak filling rate is mainly due to increased isovolumic relaxation period in hypertrophic patients. Atrial contraction contributes to more stroke volume in patients with hypertrophic cardiomyopathy.

Quantification of atrial contribution to left ventricular filling by pulsed Doppler echocardiography and the effect of age in normal and diseased hearts

Atrial filling fraction, or the fraction of stroke volume resulting from atrial contraction, was measured by Doppler echocardiography from the time-velocity integral of mitral anulus inflow with a method that allows separation of conduit or passive flow from flow resulting from the atrial contraction. The method was validated in 17 patients with externally programmable ventricular demand pacemakers by showing that the time-velocity integral of passive flow (excluding the A wave) during sinus or sequential atrioventricular pacing was almost identical to the time-velocity integral during ventricular pacing. Atrial filling fractions were then measured in 41 normal subjects, aged 20 to 80 years; 28 patients with echocardiographic evidence of concentric left ventricular hypertrophy; 24 with dilated cardiomyopathy (13 of whom had an ischemic origin); and 19 with acute myocardial infarction. Atrial filling fraction increased significantly with age in normal subjects (r = 0.77; p less than 0.001) and ranged from 12% in a 20-year-old man to 46% in a normal 80-year-old woman. In the hypertrophy group, atrial filling fraction had a weak relation with age (r = 0.47; p = 0.006), and the values were significantly higher than in normal subjects. In patients with cardiomyopathy or infarction, atrial filling fraction varied over a wide range and showed no relation to age. Thus, atrial filling fraction as determined by Doppler echocardiography is significantly altered by both age and left ventricular disease. Age-corrected nomograms are essential when assessing atrial filling fraction in individual patients.

Regional left ventricular asynchrony and impaired global left ventricular filling in hypertrophic cardiomyopathy: effect of verapamil

Left ventricular relaxation and filling are impaired in many patients with hypertrophic cardiomyopathy. To investigate the influence of regional heterogeneity on these global abnormalities, 48 patients with hypertrophic cardiomyopathy and sinus rhythm were studied by radionuclide angiography before and after 1 to 2 weeks of verapamil therapy (320 to 640 mg/day, median 480). Left ventricular regional function was assessed by subdividing the ventricular region of interest into 20 sectors and into four quadrants from which regional time-activity curves were derived. Diastolic asynchrony was measured as the regional variation in timing between minimal volume and peak filling rate, and heterogeneity in the magnitude of rapid diastolic filling was measured as the regional variation in percent contribution of atrial systole to end-diastolic volume. Compared with 28 normal subjects, the patients with hypertrophic cardiomyopathy had greater regional variation in both timing (35 +/- 24 versus 12 +/- 6 ms, p less than 0.001) and magnitude (10 +/- 6 versus 7 +/- 4%, p less than 0.02) of rapid filling. Verapamil reduced the regional variation in timing (to 21 +/- 16 ms, p less than 0.001) and magnitude (to 7 +/- 3%, p less than 0.001) of rapid filling. These regional changes, indicating more uniform regional diastolic performance after verapamil, were associated with improved global diastolic filling: global rapid filling increased in both rate and magnitude and time to peak filling rate decreased. These findings indicate that the beneficial effect of verapamil on left ventricular diastolic function in hypertrophic cardiomyopathy may be mediated by reduction in regional asynchrony.

Relation of Doppler-derived left ventricular filling parameters to age and radius/thickness ratio in normal and pathologic states

Transmitral diastolic inflow velocities determined by Doppler echocardiography have been shown to reflect left ventricular (LV) filling rates, and are therefore dependent on ventricular compliance. Radius to wall thickness ratio is an index of cavity to wall volume ratio, an important determinant of LV compliance. Accordingly, Doppler measurements of mitral anulus peak early diastolic velocity, peak atrial velocity and atrial filling fraction were made in 25 normal control subjects, mean age 46 years (range 28 to 75), and 29 patients with dilated cardiomyopathy or concentric LV hypertrophy, mean age 54 years (range 12 to 78). In addition, radius/thickness ratio was determined by 2-dimensionally guided M-mode recordings of the left ventricle. In the normal group, peak early velocity, the ratio of early to atrial velocity and atrial filling fraction correlated with age (r = -0.905, -0.823 and 0.810, respectively), but not with radius/thickness ratio. In the group with LV hypertrophy or dilatation, peak early velocity, ratio of early to atrial velocity and atrial filling fraction correlated with radius/thickness ratio (r = 0.625, 0.752 and -0.631, respectively), but not with age. Thus, with normal aging, early LV filling is reduced and atrial systole is augmented, probably reflecting intrinsic alterations in myocardial stiffness with age. In chronic LV disease, changes in radius/thickness ratio and, consequently, in chamber stiffness, influence early filling directly and atrial filling inversely, overriding the effects of age. Age-related standards are needed, however, to evaluate individual effects of a disease process on LV filling dynamics by Doppler.

Left ventricular systolic and diastolic flow abnormalities determined by Doppler echocardiography in obstructive hypertrophic cardiomyopathy

To analyze the relation of systolic anterior motion (SAM) of the mitral valve, peak left ventricular (LV) outflow tract velocity, aortic flow and mitral flow, 17 patients with obstructive hypertrophic cardiomyopathy (HC) (8 men, 9 women), aged 19 to 88 years (mean 45), were studied using M-mode and 2-dimensional echocardiography and pulsed and continuous-wave Doppler echocardiography and results were compared with those from 18 age-matched normal subjects. SAM was present in all patients with HC and absent in normal subjects. Time to peak outflow velocity as a percentage of LV ejection time was 63% in patients with HC and 29% in normal subjects (p less than 0.001). In 13 patients, time from the R-wave peak to the closest approximation of the mitral valve to the ventricular septum or initial contact during SAM was determined and was 242 +/- 66 ms and time from the R-wave peak to the peak LV outflow tract velocity was 242 +/- 73 ms (r = 0.90). In 11 patients time from the R-wave peak to cessation of flow in the ascending aorta was measured and was 286 +/- 80 ms; time from the R-wave peak to the peak LV outflow tract velocity was 246 +/- 75 ms. The ratio of early to late diastolic filling velocities of the left ventricle was 1.47 +/- 0.40 in the normal subjects and 1.26 +/- 0.84 in patients with HC (difference not significant). The early to late ratio of the 12 patients without mitral regurgitation was 0.99 +/- 0.52 (p less than 0.01 vs normal subjects).(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular function during physiological cardiac pacing: relation to rate, pacing mode, and underlying myocardial disease

The hemodynamic effects of cardiac pacing at different rates and in different modes were studied in 21 patients who were candidates for permanent pacemaker implantation. Nine of these had primary conduction disturbances (PCD), ten had ischemic heart disease (IHD), seven with additional cardiac failure (CHF), and two had hypertrophic cardiomyopathy (HCM). In patients with PCD, atrial (AOO) and AV sequential (DVI) pacing did not change systolic blood pressure and pulse pressure but ventricular (VVI) pacing caused a progressive fall in these measurements, especially as heart rate increased. Ventricular volume and stroke volume (counts) derived from radionuclide ventriculography (RVG) decreased progressively with higher pacing rates, especially during VVI pacing. Cardiac output was maintained during VVI pacing by the increase in heart rate; during AOO and DVI pacing, cardiac output increased. Similar but more marked differences were observed in patients with IHD and CHF and the changes were even greater in the patients with HCM. Left ventricular (LV) ejection fraction changed little with increasing heart rate in PCD but decreased progressively with the onset of ischemia in IHD and CHF. There was no difference in ejection fraction in the different pacing modes. Graphs related to LV contractility (end-systolic pressure-volume relations) showed that AOO pacing produced the highest and VVI pacing produced the lowest curves of myocardial contractility in all patient groups, except that at higher rates the AOO curve shifted down again in patients with IHD and CHF, presumably with the onset of myocardial ischemia. This study showed that physiological pacing produced the best hemodynamic results in all patient groups. Higher pacing rates should be avoided in patients with ischemic heart disease while VVI pacing should not be used in patients with HCM. Blood pressure and RVG studies during temporary pacing are useful in selecting the optimal pacing system in an individual patient when the clinical choice is not clear.

Effects of verapamil on left ventricular diastolic function at rest and during isometric exercise in patients with hypertrophic cardiomyopathy

Ten patients with hypertrophic cardiomyopathy were examined with echocardiography before and during verapamil treatment to evaluate short-term and long-term effects of verapamil on left ventricular diastolic function. All patients were in sinus rhythm and in NYHA functional class I. Effects on filling and myocardial relaxation were documented by digitized echocardiography obtained at rest and during isometric exercise before treatment, after two weeks (short-term) and four months (long-term) treatment, respectively. At rest a significant decrease of the myocardial relaxation time was found during verapamil treatment. A few patients, however, returned to almost baseline conditions after an initial improvement. A small increase in the peak rate of dimension change, a parameter of filling, reached statistical significance at the end of the long-term treatment period. Isometric exercise did not induce any changes in the diastolic parameters during verapamil treatment. A positive effect of verapamil was thus seen on both myocardial relaxation and left ventricular filling, but only in resting conditions.

Left ventricular diastolic function in weight lifters

Concentric left ventricular (LV) hypertrophy and asymmetric septal hypertrophy have both been described in weight lifters, but diastolic filling, which is abnormal in pathologically hypertrophied ventricles, has not been investigated in such subjects. Accordingly, pulsed Doppler examination of LV inflow, M-mode and 2-dimensional echocardiography were performed in 16 competitive weight lifters and 10 age-matched male control subjects. Peak and mean filling rates were determined in milliliters per second as the product of the cross-sectional area of the mitral anulus and the Doppler-derived peak early and mean transmitral inflow velocities, respectively. Rapid filling index was defined as peak filling rate divided by mean filling rate. Flow velocity integrals of the early and atrial diastolic filling phases were also measured. LV end-diastolic volume and ejection fraction were measured using 2-dimensional echocardiography. Weight lifters had significantly higher LV end-diastolic volume (181 +/- 50 vs 136 +/- 40 ml, p less than 0.05) and dimension (5.6 +/- 0.6 vs 5.1 +/- 0.5 cm, p less than 0.05), and posterior wall thickness (0.9 +/- 0.2 vs 0.8 +/- 0.1, p less than 0.05); however, after correction for body surface area there was no significant difference in these values. Weight lifters had significantly higher LV mass (241 +/- 70 vs 165 +/- 29, p less than 0.02) and LV mass index (114 +/- 29 vs 87 +/- 15 g/m2, p less than 0.05). There was no significant difference between the weight lifters and control subjects in rapid filling index, early to late integral ratio or ejection fraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of verapamil on haemodynamic function and myocardial metabolism in patients with hypertrophic cardiomyopathy

The effect of 20 mg dose of intravenous verapamil was studied over a range of heart rates in 12 patients with hypertrophic cardiomyopathy. Six patients had an appreciable left ventricular outflow tract gradient and six did not. The drug reduced myocardial oxygen consumption in proportion to a reduction in the development of left ventricular pressure. The negative inotropic effect of verapamil was counteracted by the drug's non-specific vasodilator activity, so that cardiac index was unaltered at any heart rate and as a result myocardial efficiency was unaffected by the drug. Verapamil did not consistently alter myocardial metabolism. Some patients showed improvement in anaerobic myocardial metabolism after verapamil but an equal number showed impairment of lactate metabolism. It was not possible to predict from clinical features, echocardiographic findings, or haemodynamic variables measured before administration of verapamil which patients would demonstrate haemodynamic or metabolic improvement after the drug. In this short term study no mechanism was demonstrated by which patients with hypertrophic cardiomyopathy might obtain a consistent improvement from treatment with verapamil.

Left ventricular diastolic filling and its association with age

Thirty normal subjects, aged 22 to 80 years, were studied by radionuclide ventriculography to determine the age dependence of cardiac ventricular diastolic function and to evaluate the association of other factors with ventricular diastolic performance. A strong negative correlation was found between peak diastolic filling rate and age (r = -0.82, p less than 0.0001). Partial correlation analysis was used to factor out the strong age dependence and yielded additional significant correlations of peak filling rate with heart rate (r = 0.48, p less than 0.01) and time to peak filling rate (r = -0.48, p less than 0.01). Time to peak filling rate is also correlated with heart rate but not definitely with age. Analysis by multiple linear regression yields an equation predicting peak filling rate from age and heart rate. Thus, the rate of rapid diastolic filling declines markedly with age in normal subjects. The association of peak filling rate with age and with other factors indicates the need for careful consideration of these factors in the interpretation of scintigraphic findings in patients with heart disease.

Left ventricular filling in hypertrophic cardiomyopathy: a pulsed Doppler echocardiographic study

Abnormal left ventricular diastolic properties have been described in patients with hypertrophic cardiomyopathy. To evaluate the diastolic filling characteristics of the left ventricle in patients with this disease, pulsed Doppler echocardiography was used to study mitral flow velocity in 17 patients with hypertrophic cardiomyopathy (11 with and 6 without systolic anterior motion of the mitral valve) and 16 age-matched normal subjects. There were no statistically significant differences between patients with hypertrophic cardiomyopathy with and without systolic anterior motion with regard to ventricular septal thickness, left ventricular posterior wall thickness, left ventricular internal dimensions or the extent of hypertrophy evaluated by two-dimensional echocardiography. Mitral regurgitation was detected by Doppler echocardiography in all 11 patients with and in 2 (33%) of the 6 patients without systolic anterior motion of the mitral valve. Early and late diastolic peak flow velocity, the ratio of late to early diastolic peak flow velocity and deceleration of early diastolic flow were measured from Doppler mitral flow velocity recordings. There were no statistically significant differences in these four indexes between the patients with systolic anterior motion and normal subjects. In contrast, the patients with hypertrophic cardiomyopathy without systolic anterior motion showed lower early diastolic peak flow velocity, higher ratio of late to early diastolic peak flow velocity and lower deceleration of early diastolic flow compared with the patients with systolic anterior motion and normal subjects, suggesting impaired left ventricular diastolic filling.(ABSTRACT TRUNCATED AT 250 WORDS)

The mechanism of disappearance of the physiologic third heart sound with age

To study the mechanism of disappearance of the physiologic third heart sound (S3) with advancing age, combined phonoechocardiographic and phonomechanocardiographic recordings from 165 normal subjects between 6 and 62 years old were quantitatively analyzed. Nearly all individuals under 40 years old had a recordable S3. Although recordable in 38.6% of the 44 subjects over 40 years old, the physiologic S3 found in adults was less intense and occurred later in diastole when compared with that in children and adolescents. Marked changes in left ventricular filling hemodynamics were observed with aging, including an increase in left ventricular wall thickness and mass, a prolongation of the left ventricular isovolumetric relaxation period, a decrease in left ventricular early diastolic filling and wall thinning rates, and a reduction in the height and steepness of the rapid filling wave measured on the calibrated left apexcardiogram (linear correlation with age significant at p less than .001 for all parameters). Although less pronounced, these changes were very similar to the diastolic abnormalities found in patients with pressure overload left ventricular hypertrophy. Therefore, the higher pressure load imposed on the left ventricular wall due to the well-known gradual increase in blood pressure that occurs during normal growth and adulthood appears to be the most likely explanation for the observed changes in diastolic filling. It is concluded that the later occurrence, the diminishing amplitude, and the eventual complete disappearance of the physiologic S3 with age results from a decrease in early diastolic left ventricular filling and subsequent deceleration of inflow caused by the development of relative left ventricular hypertrophy in adulthood as compared with childhood.

Echocardiographic evaluation of verapamil in Friedreich's ataxia

Nine patients with hypertrophic cardiomyopathy associated with Friedreich's ataxia were treated with the calcium antagonist verapamil, which is known to reduce myocardial hypertrophy and improve diastolic function in patients with idiopathic hypertrophic cardiomyopathy. Daily oral doses of 7 mg/kg were given for a mean (SD) of 24 (8) months. M mode echocardiography performed at the start of the study and at the end of follow up showed no significant difference between the treated group and an untreated control group of nine patients. Verapamil produced no changes in left ventricular wall thickness, mass index, left ventricular internal diameter, fractional shortening, peak normalised lengthening rate, peak rate of septal and posterior wall thinning, and time from minimum ventricular cavity dimension to mitral valve opening. Myocardial calcium overload has been suggested as a cause of cardiac disease in Friedreich's ataxia; however, verapamil had no beneficial effect on these patients with established myocardial hypertrophy.

Noninvasive assessment of left ventricular diastolic function: comparative analysis of Doppler echocardiographic and radionuclide angiographic techniques

This investigation was performed to determine whether variables obtained directly from the Doppler left ventricular diastolic flow velocity profile provide a reliable estimate of diastolic function. Measurements of diastolic flow velocity obtained by Doppler echocardiography were compared with volumetric measurements of left ventricular diastolic filling determined by radionuclide angiography in 12 subjects without cardiac disease and in 25 patients with a variety of cardiac diseases. The two methods were in agreement in distinguishing normal from abnormal diastolic function in 21 (84%) of the 25 patients with cardiac disease, identifying diastolic function as normal in 8 and abnormal in 13 of these patients. Good correlations were observed between certain Doppler variables of left ventricular diastolic flow velocity and radionuclide angiographic variables of left ventricular filling. The time interval from the aortic closing component of the second heart sound to the end of the early diastolic flow velocity peak, assessed with Doppler echocardiography, correlated well with the time interval from end-systole to the end of rapid filling, assessed with radionuclide angiography (r = 0.83). Descent of the Doppler early diastolic flow velocity peak correlated well with the radionuclide angiographic peak filling rate (r = 0.79). The ratio between the heights of the early and late (due to atrial systole) peaks of diastolic flow velocity showed good correlation with the ratio between percent of left ventricular filling during rapid filling and during atrial systole (r = 0.76). These findings demonstrate that the left ventricular diastolic flow velocity profile obtained with Doppler echocardiography compares favorably with radionuclide angiographic variables in the evaluation of left ventricular diastolic function.(ABSTRACT TRUNCATED AT 250 WORDS)

Isovolumic relaxation period in hypertrophic cardiomyopathy: assessment by radionuclide angiography

Left ventricular isovolumic relaxation and the relation between relaxation and filling were studied in 90 patients with hypertrophic cardiomyopathy and 29 control subjects using radionuclide angiography. The isovolumic relaxation period was determined automatically on left ventricular time-activity curves as the interval between minimal volume and onset of rapid filling. In 17 patients, M-mode echocardiography performed simultaneously with radionuclide angiography demonstrated that onset of mitral valve opening correlated well with onset of rapid filling (r = 0.84, p less than 0.001). The isovolumic relaxation period was longer in patients with hypertrophic cardiomyopathy than in control subjects (95 +/- 44 versus 50 +/- 23 ms, p less than 0.01) and was longer in patients without an outflow tract gradient at rest than in patients with a gradient (109 +/- 37 versus 86 +/- 35 ms, p less than 0.05). In these patients without obstruction, a weak linear relation between duration of the isovolumic period and peak filling rate was found (r = 0.48, p less than 0.02). Filling was impaired in patients with hypertrophic cardiomyopathy, as assessed by lower peak filling rate (3.2 +/- 1.2 versus 3.5 +/- 0.5 end-diastolic volume/s, p less than 0.05) and prolonged time to peak filling rate (185 +/- 44 versus 145 +/- 20 ms, p less than 0.01) compared with values in control subjects. The delay in time to peak filling rate was caused primarily by the prolonged isovolumic period, because the interval from onset of rapid filling to peak filling rate was similar in patients with hypertrophic cardiomyopathy and control subjects (87 +/- 31 versus 95 +/- 25 ms, NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of left ventricular diastolic filling: comparison of fixed and varying region of interest approaches

Abnormalities in scintigraphic measurements of diastolic filling were assessed with respect to detection, reproducibility and sensitivity by means of fixed and varying left ventricular region-of-interest (ROI) approaches. Equilibrium blood pool scintigraphy was carried out in 11 control subjects, 15 patients with coronary artery disease (CAD), and 13 patients with hypertension. Results of these studies were analyzed for ejection fraction (EF), peak filling rate (PFR), time to PFR (TPFR), and filling fraction in the first third of diastole corrected for cycle length (FF1/3). With the fixed ROI technique, patients with CAD differed from the control subjects because they had lower EF (p less than 0.05), PFR (p less than 0.001), and FF1/3 (p less than 0.05) levels; patients with hypertension showed only a reduced FF1/3 (p less than 0.01). When the varying ROI method was employed, patients with CAD differed from normal subjects in their PFR (p less than 0.05) results; patients with hypertension and normal subjects differed in their FF1/3 (p less than 0.001) results. Although the ability to discriminate between patients and normal subjects was similar with the two techniques, interobserver variability was smaller and single observer reproducibility was greater with the fixed ROI method. We conclude that the fixed and varying ROI techniques are comparable in detecting diastolic filling abnormalities but that the fixed ROI method is superior in reducing measurement variability and may be the preferable method for analyzing serial studies and the response to therapeutic interventions.

Verapamil-induced improvement in left ventricular diastolic filling and increased exercise tolerance in patients with hypertrophic cardiomyopathy: short- and long-term effects

Verapamil improves exercise tolerance and decreases symptoms in many patients with hypertrophic cardiomyopathy. The mechanisms responsible for these effects are not completely understood, although previous studies indicate that verapamil enhances left ventricular relaxation and diastolic filling in such patients. To investigate the association between changes in left ventricular filling and exercise tolerance after verapamil, we studied 55 patients with hypertrophic cardiomyopathy by radionuclide angiography and graded treadmill testing before and after 1 to 4 weeks of therapy with orally administered verapamil, 320 to 640 mg/d. The verapamil-induced increase in peak left ventricular filling rate at rest (from 3.1 +/- 1.3 to 3.7 +/- 1.3 end-diastolic volumes/sec; p less than .001) was associated with an increase in exercise tolerance (from 5.9 +/- 3.6 to 8.7 +/- 4.7 min; p less than .001); exercise capacity increased in 34 of 43 patients (79%) manifesting an increase in peak filling rate but only one of 12 patients (8%) with unchanged or decreased peak filling rate (p less than .001). This initial trend persisted in 25 patients studied after 1 year of therapy; 11 of 16 patients (69%) with a persistent increase in peak filling rate had persistent improvement in exercise tolerance relative to preverapamil values, compared with only one of nine patients (11%) in whom peak filling rate was unchanged or decreased relative to preverapamil levels (p less than .02). Verapamil withdrawal after 1 to 2 years in 24 patients resulted in reduction in peak filling rate (p less than .001) and was associated with deterioration in exercise tolerance in 17 patients (71%). Hence, verapamil-induced changes in left ventricular peak filling rate were associated significantly with objective symptomatic improvement. These data support the concept that enhanced left ventricular diastolic filling is an important mechanism contributing to the clinical improvement experienced by many patients with hypertrophic cardiomyopathy during therapy with verapamil.

Left ventricular filling is usually normal in uncomplicated coronary disease

Abnormalities in left ventricular filling have been described as an early finding in coronary artery disease (CAD) and more recently, in hypertension (HTN). The present study was undertaken to compare the prevalence and pattern of diastolic dysfunction in these two entities. Three groups of patients were studied: 10 normal volunteers (NLS), 39 HTN patients, and 30 CAD patients. The CAD patients were divided into two subgroups--one with normal ejection fraction (mean 0.60 +/- 0.06) and the second with either a depressed ejection fraction (EF) or a history of HTN (mean EF 0.44 +/- 0.15). The diastolic indices examined were peak filling rate (PFR, in end-diastolic volume [EDV]/sec), time to peak filling rate (TPFR, in msec), and first-third filling fraction (FF 1/3, in sec-1). The PFR in CAD and HTN was significantly reduced (1.86 +/- 0.63 and 2.29 +/- 0.49 vs 2.70 +/- 0.35 EDV/sec in NLS, p less than 0.025 and p less than 0.001, respectively), with the CAD group also being significantly lower than the HTN group (p less than 0.005). TPFR was prolonged in HTN, but not in CAD. FF 1/3 was reduced in both HTN and CAD (0.38 +/- 0.11 and 0.50 +/- 0.14 vs 0.61 +/- 0.06 sec-1 in NLS, p less than 0.001 and p less than 0.025, respectively), but it was significantly lower in HTN than in CAD (p less than 0.001). However, when the subgroup of CAD patients with normal global systolic function was examined separately, diastolic indices were only slightly depressed. More importantly, only one, two, and five patients had PFR, TPFR, and FF 1/3, respectively, which were below the normal values of our laboratory.

Hypertrophic cardiomyopathy. The importance of the site and the extent of hypertrophy. A review

Hypertrophic cardiomyopathy is a diverse clinical and pathophysiologic entity that involves principally the left ventricle and is caused by asymmetric or concentric hypertrophy of unknown cause. If asymmetric, the hypertrophy is usually greatest in the ventricular septum, but variations occur in which the hypertrophy may be maximal at the apex, at the midventricular level, or, rarely, in the free wall of the left ventricle. Right ventricular involvement is usually less evident. The principal abnormality in systole is the obstruction to left ventricular outflow caused by upper septal hypertrophy narrowing the outflow tract and setting the stage for Venturi forces to cause systolic anterior motion of the anterior or posterior mitral leaflets. The time of onset and duration of mitral leaflet-septal contact determine the magnitude of the pressure gradient. Mitral regurgitation invariably accompanies the obstruction to outflow. Ventriculomyotomy-myectomy surgery, by thinning the septum and widening the outflow tract, abolishes the abnormal mitral leaflet motion and, consequently, the obstruction to outflow and the mitral regurgitation. This form of surgery more dramatically relieves the systolic abnormalities and the accompanying symptoms than any form of medical therapy available today. The extent of hypertrophy is believed to be the principal determinant of the impaired left ventricular relaxation and increased chambers stiffness (decreased compliance) that characterize diastole in hypertrophic cardiomyopathy. Relaxation is impaired by the contraction load (the obstruction), by a decrease in the principal relaxation loads, by a pathologic degree of nonuniformity of contraction and relaxation, and in all likelihood, by impaired inactivation of the biochemical processes responsible for contraction (? due to primary or ischemia-induced calcium overload). Calcium channel-blocking agents may dramatically improve left ventricular relaxation by speeding up the inactivation process, by decreasing the degree of nonuniformity, or by altering the contraction and relaxation loads in a favorable manner. Atrial and ventricular arrhythmias are responsible for a significant proportion of the morbidity and mortality, and their occurrence also appears to depend on the extent of hypertrophy. Thus, the major manifestations of hypertrophic cardiomyopathy in systole and diastole as well as the disturbances of rhythm appear to be related to the site and/or extent of the hypertrophic process.(ABSTRACT TRUNCATED AT 400 WORDS)

Ejection fraction and heart rate correlate with diastolic peak filling rate at rest and during exercise

We investigated the independent variables correlating with the multigated radionuclide peak filling rate (PFR) at rest and during supine bicycle exercise in 20 normal individuals. Independent variables were systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), ejection fraction (LVEF), time to PFR (TPFR), peak ejection rate (PER) and time to PER (TPER). Fifteen subjects completed at least five stages of exercise at 25 watts each. Correlating independent variables were selected by a forward-backward stepwise multiple linear regression (BMDP2R). A partial correlation statistical program was also used to allow control of critical independent variables. The final regression equations were: a) resting state, PFR = -2.5 + 0.03HR + 0.05LVEF + 0.02SBP-0.02DBP, and b) exercise state, PFR = -3.8 + 0.04HR + 0.08LVEF. All independent variables mentioned above correlated with PFR (simple correlations designated as zero partials). However, when LVEF and HR were held constant (second order partials), the correlation of PFR with any of the other independent variables disappeared. In summary, the radionuclide global LV PFR is predominantly correlated to LVEF and HR at rest and during exercise. These correlations should be considered when assessing exercise effects of disease states on PFR.

Effects of calcium-channel blocking agents on left ventricular diastolic function in hypertrophic cardiomyopathy and in coronary artery disease

Abnormal left ventricular (LV) diastolic performance is a characteristic feature of hypertrophic cardiomyopathy (HC) and an important contributor to the development of symptoms. Impaired diastolic filling of the hypertrophied left ventricle results from both diminished distensibility and prolonged or incomplete relaxation. LV distensibility is not only influenced by fixed anatomic abnormalities (such as fibrosis or hypertrophy) that determine the passive elastic properties of the left ventricle, but also is modulated by the dynamics of myocardial relaxation: prolonged or incomplete LV relaxation may restrict the rate and extent of LV filling and result in altered pressure-volume relations throughout diastole. Several studies indicate that impaired LV relaxation and filling in HC may be modified favorably by verapamil or nifedipine administered on a short-term basis in the catheterization laboratory, associated with improved diastolic pressure-volume relations. Verapamil also improves LV filling during oral therapy. Improved indexes of LV filling correlate with symptomatic improvement, both short-term and long-term: Approximately 80% of patients having a persistent increase in peak LV filling rate have persistent improvement in objective exercise tolerance compared with preverapamil values. Altered LV relaxation and filling are also often observed in patients with coronary artery disease (CAD) after myocardial infarction or during acute ischemia. Moreover, impaired filling occurs under resting conditions in many patients who have normal systolic function and no evidence of previous infarction. Nifedipine improves indexes of LV relaxation and distensibility during pacing-induced ischemia and verapamil improves indexes of LV filling at rest and during exercise-induced ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Failure of antihypertensive therapy with diuretic, beta-blocking and calcium channel-blocking drugs to consistently reverse left ventricular diastolic filling abnormalities

The present protocol was designed to determine whether antihypertensive therapy with hydrochlorothiazide, propranolol or diltiazem, 3 agents with different mechanisms of action and potentially different effects on myocardial function, reverses left ventricular filling abnormalities. Twelve patients with essential hypertension and no evidence of associated cardiovascular disease, either clinically or with noninvasive testing, were evaluated while taking no medication and after 2 months of treatment with these agents. All 3 drugs produced equivalent control of blood pressure (BP), reducing sitting systolic BP by a mean of 20 to 24 mm Hg and diastolic BP by 14 to 16 mm Hg. LV ejection fraction and end-diastolic volume were normal in all but 1 subject (who was excluded from the analyses of LV diastolic filling) and were not altered by drug therapy. The peak LV filling rate and the first-third filling fraction were reduced in the patients with hypertension, but neither of these indexes nor the time to peak filling rate were significantly improved for the group as a whole by any of these medications. Nine of 10 patients whose BP was controlled by diltiazem had increases in their first-third filling fraction, but this change did not reach statistical significance. Our findings suggest that abnormalities of LV diastolic filling are not consistently affected by short-term therapy in patients with chronic, previously treated systemic hypertension.

Verapamil: a cause of sudden death in a patient with hypertrophic cardiomyopathy

Sudden death was recorded by continuous ambulatory electrocardiographic (Holter) monitoring in a 62 year old man with hypertrophic cardiomyopathy and atrial fibrillation, who had been treated for four days with verapamil 360 mg orally. Analysis of the tape showed a third degree atrioventricular block followed by complete asystole. The sudden death could be related to treatment with verapamil.