Diastolic dysfunction in exercise and its role for exercise capacity

Diastolic dysfunction is frequent in elderly subjects and in patients with left ventricular hypertrophy, vascular disease and diabetes mellitus. Patients with diastolic dysfunction demonstrate a reduced exercise capacity and might suffer from congestive heart failure (CHF). Presence of symptoms of CHF in the setting of a normal systolic function is referred to as heart failure with normal ejection fraction (HFNEF) or, if evidence of an impaired diastolic function is observed, as diastolic heart failure (DHF). Reduced exercise capacity in diastolic dysfunction results from a number of pathophysiological alterations such as slowed myocardial relaxation, reduced myocardial distensibility, elevated filling pressures, and reduced ventricular suction forces. These alterations limit the increase of ventricular diastolic filling and cardiac output during exercise and lead to pulmonary congestion. In healthy subjects, exercise training can enhance diastolic function and exercise capacity and prevent deterioration of diastolic function in the course of aging. In patients with diastolic dysfunction, exercise capacity can be enhanced by exercise training and pharmacological treatment, whereas improvement of diastolic function can only be observed in few patients.     

Effects of ischemia, bypass surgery and past infarction on myocardial contraction, relaxation and compliance during exercise

Abnormalities of left ventricular function during ischemia have been described in animal models and in humans. Exercise, while a physiologic means of inducing ischemia, has a complex effect on left ventricular function by itself. In addition, patients with coronary artery disease have a diversity of chronic changes in myocardial structure and function. Therefore, with use of micromanometer left ventricular pressure measurements and ventricular volumes, calculated from biplane cineangiograms, left ventricular function at rest and during exercise was studied in 57 patients. Exercise-induced ischemia produced a decrease in ejection fraction, an increase in end-systolic volume, dramatic increases in diastolic pressures and an upward shift in the diastolic pressure-volume relation. Central to these changes was abnormal myocardial contraction and relaxation, with reduced regional shortening and impaired left ventricular pressure decay. However, nonischemic areas were capable of augmented shortening, and global pressure decay did accelerate slightly. These findings demonstrate that exercise-induced adjustments in contraction and relaxation are intertwined with ischemia-related abnormalities. Exercise studies in patients after bypass surgery and in patients with scars from distant myocardial infarction were useful in clarifying confounding factors. For example, asynchrony of contraction and relaxation, and chronic changes in passive chamber properties, also compromise systolic and diastolic function during exercise. In patients with coronary artery disease without ischemia during exercise, left ventricular end-diastolic pressure, but not early diastolic pressure, increased during exercise. The increase in pressure was appropriate for a slight increase in end-diastolic volume in a ventricle with a steep pressure-volume relation. Furthermore, end-systolic volume, while maintained during exercise, was not reduced, as occurs normally.(ABSTRACT TRUNCATED AT 250 WORDS)     

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)     

Rest and exercise left ventricular ejection and filling characteristics following orthotopic cardiac transplantation

High temporal resolution radionuclide angiography was performed in 24 normal volunteers and 31 healthy cardiac transplant recipients two to 43 months (mean 13 +/- 14 months) postoperatively in order to obtain cardiac volumes and parameters of left ventricular ejection and filling at rest and during supine exercise. The peak left ventricular ejection rate was significantly higher in transplant patients at rest (2.73 +/- 0.62 versus 1.98 +/- 0.29, P less than 0.0001). During submaximal exercise, however, in contrast to normal subjects, peak ejection rate increased in transplant recipients only during later exercise, corresponding to an increase in heart rate. Peak left ventricular filling rate was also significantly higher among transplant recipients at rest (3.52 +/- 0.96 versus 2.36 +/- 0.45, P less than 0.0001) and during submaximal exercise. Peak filling rate increased in transplant patients on initiation of exercise, associated with an increase in the end diastolic volume in the absence of an increase in heart rate. In 13 patients studied more than one year post cardiac transplantation, the peak ejection rate and peak filling rates did not differ from those studied less than one year post transplant. Therefore, in transplant patients, no defect of myocardial filling was apparent either at rest or during exercise. Systolic performance improved in later exercise, presumably as levels of circulating catecholamines and heart rate increased.     

Dynamics of left ventricular diastolic filling during exercise: a Doppler echocardiographic study of boys 10 to 14 years old.

STUDY OBJECTIVE: Factors influencing diastolic filling of the left ventricle may serve as critical determinants of both maximal cardiac output and oxygen uptake. This study was conducted to assess diastolic filling dynamics of the left ventricle during progressive upright cycle exercise in children. METHODS: Twelve boys aged 10 to 14 years underwent cycle testing with determination of transmitral flow velocities and pressure gradients as well as cardiac stroke volume using Doppler echocardiography. RESULTS: Estimated diastolic filling period shortened from 0.479 +/- 0.043 s at rest to 0.138 +/- 0.015 s at peak exercise. The peak and mean transmitral pressure gradient rose fourfold from rest to peak exercise. Mitral flow volume per beat rose by only 40% and remained stable beyond mild-to-moderate intensity work. CONCLUSIONS: Increases in transmitral pressure gradient with exercise may serve principally to augment velocity of ventricular filling with the progressively shortening diastolic time period.     

"Diastolic" heart failure and pulsed pressure

Cardiac failure is the leading cause of hospital admission after 65 years of age. Several studies have confirmed the frequency of cardiac failure with normal systolic function ("diastolic" cardiac failure) in the elderly (nearly half the cases). The cause is commonly isolated systolic hypertension. The pulsed pressure depends on ventricular ejection, arterial rigidity and the precocity of reflected pulse waves. In the elderly, the pulse pressure is a powerful predictive factor for mortality and adverse cardiovascular events (acute coronary syndromes, cardiac failure and cerebrovascular accidents). Patients with isolated systolic hypertension or an increased pulsed pressure usually have left ventricular hypertrophy or concentric remodelling, abnormal relaxation, alteration of hypertrophied myocytes with increased myocardial oxygen consumption and subendocardial ischaemia, especially when the coronary reserve is reduced. The decrease of the diastolic blood pressure reduces the presence of coronary perfusion. Moreover, an increase in the pulsed pressure predisposes to coronary atherosclerosis. These patients are very symptomatic on exercise because they do not have a reserve of preload and easily develop acute pulmonary oedema after a volume overload (increased salt intake, postoperative rehydratation). A recent study showed that the left ventricular ejection fraction was preserved during acute pulmonary oedema of hypertensive patients. The diagnosis of "diastolic" cardiac failure is often suspected by elimination (clinical signs of cardiac failure with a normal left ventricular ejection fraction), and echographers have proposed many criteria to detect abnormal relaxation, filling or distensibility of the left ventricle. Mortality would seem to be half that of systolic cardiac failure. Treatment should normalise the hypertension, ischaemia, tachycardia, and maintain or reestablish sinus rhythm, but it remains empirical.     

Systolic and diastolic left ventricular dysfunction in middle-aged asymptomatic non-insulin-dependent diabetics.

Radionuclide ventriculographic studies were performed at rest and during exercise in 15 middle-aged asymptomatic patients with non-insulin-dependent diabetes mellitus (NIDDM) whose mean age was 58.7 +/- 10.5 years (mean +/- SD), and in 10 age- and sex-matched normal control subjects. The patients had neither clinical evidence of cardiovascular diseases nor obvious perfusion defects during maximal exercise testing with thallium-201 myocardial scintigraphy. The average left ventricular ejection fraction (LVEF) at rest was 69.1 +/- 5.3% in the diabetic patients and 65.6 +/- 4.2% in the control subjects, and during exercise, the average LVEFs were 68.3 +/- 6.9% and 72.1 +/- 5.0%, respectively. The changes in LVEF during exercise were -0.7 +/- 7.6% in the diabetic group and +6.5 +/- 2.6% in the control group (p < 0.01). However, the filling fraction during the first third of diastole at rest was significantly less in the diabetic group than in the control group (p < 0.05), the time to peak filling rate (TPF) was longer, and the TPF/R-R, normalized by the R-R interval and expressed as a percentage, was greater in the NIDDM patients than in the control subjects. There was close correlation between the abnormal response of LVEF to exercise and the reduced early diastolic filling in the diabetic patients. We concluded that 1) not only the response of LVEF to exercise but also the early left ventricular diastolic filling at rest are impaired in middle-aged asymptomatic NIDDM patients, and 2) some common factors could cause dysfunction of both the systolic and diastolic left ventricles in NIDDM patients, possibly latent global myocardial ischemia or metabolic myocardial disturbances.     

Nifedipine, but not propranolol, improves left ventricular systolic and diastolic function in patients with hypertension

The effects of nifedipine and propranolol on cardiac function both at rest and at peak exercise were compared in 22 hypertensive patients whose diastolic blood pressures remained in excess of 95 mm Hg despite diuretic therapy. In this double-blind, placebo-controlled study, left ventricular systolic and diastolic function at rest and at peak exercise during bicycle ergometry was assessed by first-pass radionuclide angiography using the Baird Scinticor before and after treatment with either nifedipine or propranolol. Both agents effectively reduced blood pressure in the supine and upright positions and at peak exercise. Nifedipine was associated with a significant increase in cardiac output and stroke volume at rest and at peak exercise, while propranolol decreased cardiac output at rest and at peak exercise. Systemic vascular resistance decreased with nifedipine treatment at rest and at peak exercise, but increased significantly with propranolol. Nifedipine increased ejection fraction in patients at rest and also increased maximal oxygen consumption at peak exercise, while propranolol decreased maximal oxygen consumption at peak exercise. At rest and at peak exercise, nifedipine increased peak filling rate, but time to peak filling rate was not affected by either drug. The fraction of total diastolic filling at the midpoint of diastole was significantly increased by nifedipine therapy at rest but was not affected by propranolol therapy. Nifedipine significantly decreased atrial filling volume while propranolol had no effect. Propranolol therapy did not result in any improvement in left ventricular function. In contrast, nifedipine improved left ventricular systolic and diastolic function at rest and peak exercise. Future selection of an antihypertensive agent should include consideration of the impact of therapy on left ventricular function.     

Prognostic relevance of left ventricular diastolic function parameters in dilated cardiomyopathy

Patients with dilated cardiomyopathy (DCM) generally have an impaired functional capacity and poor long-term out-comes. A mortality of 5-15% per year has been described actually. Aim of this study was to verify the prognostic relevance of invasive and non-invasive parameters of diastolic function in patients with DCM. In 33 patients with DCM, cardiac catheterization was performed and left ventricular systolic (ejection fraction (EF; %)); left ventricular enddiastolic pressure (LVEDP; mmHg) and diastolic function (time constant of relaxation (T, ms); the constant of myocardial stiffness (b) were derived from biplane laevocardiography and simultaneous micromanometric registration of pressure-volume curves. For evaluation of clinical out-come, the follow-up period was defined as beginning on the day after cardiac catheterization and ending on the most recent date or with a cardiac event (death or cardiac transplantation). All patients were reevaluated for NYHA functional class and completed a standard questionnaire. The following hemodynamic parameters were evaluated: invasive parameters of left ventricular diastolic function (constant of relaxation: tau (ms), constant of myocardial stiffness: b)), as well as parameters of systolic function (ejection fraction (EF; %)), left ventricular pressure (LVEDP; mmHg), left ventricular muscle mass index (LVMMI; g/m2), left ventricular enddiastolic volume index (LVEDVI; ml/m2) and non-invasive parameters of morphological data, left ventricular systolic (fractional shortening (FS, %) and ejection fraction) and diastolic parameters with echocardiography. During the follow-up period of 36 months, 11 of 33 patients experienced a major cardiac event (cardiac death n = 8, heart transplantation n = 3). The major cause of death was progressive pump failure. The remaining 22 patients were further classified with respect to changes in functional status. While clinical symptoms could be improved medically in patients with moderate increase of myocardial stiffness, patients with severe increase of myocardial stiffness (b: 76.1 +/- 12.1 vs 17.9 +/- +8.1, p < 0.001) could not be improved and suffered more cardiac events. Doppler echocardiographic measurements in these patients showed a restrictive filling pattern (VE 0.91 +/- 0.21 vs 0.64 +/- 0.18 m/s; p < 0.01; VA 0.52 +/- 0.23 vs 0.57 +/- 0.24 m/s; p < 0.01, deceleration time 129 +/- 17 vs 211 +/- 14 ms; p < 0.01). The medical heart failure therapy was comparable in both groups. In patients with cardiac events, the diastolic left ventricular variables did not significantly differ between patients who underwent heart transplantation and those who died. Patients who demonstrated a sole impairment of relaxation (tau: > 50 ms) suffered no cardiac events. Impaired diastolic function contributes to the clinical picture of congestive heart failure. Parameters of left ventricular diastolic function are powerful and important predictors of major cardiac events in patients with DCM, like heart transplantation and non-sudden death, and may indicate future clinical success of medical treatment. Invasive and non-invasive parameters of diastolic function reveal comparable information for the estimation of prognosis of patients with DCM in order to initiate early therapy.     

Adaptation of the left ventricle function to exercise in aortic stenosis. Study with cavitary angioscintigraphy

Eighteen patients with pure aortic stenosis without coronary artery disease underwent equilibrium radionuclide angiography to evaluate the adaptation of their left ventricular function to exercise. The left ventricular ejection fraction, peak left ventricular ejection, and fillings, and their timing were calculated from time-activity curves and their first derivatives at rest and at the maximum of exercise. There were no clinical complications. The ST segment and T wave changes of 14 patients were accentuated and 3 patients developed anginal pain. The ejection fraction was normal at rest and did not change significantly during exercise. The peak ejection did not vary but peak left ventricular filling was prolonged by exercise. There was a correlation between peak ventricular ejection at rest and the aortic valve surface area at catheterisation. This isotopic parameter was inversely correlated with LVEDP. There was a close correlation between age and peak ventricular filling on exercise. The variation between resting and exercise values of this parameter was inversely correlated with age. This study shows that exercise stress testing can be undertaken without risk in patients with aortic stenosis. The results of radionuclide angiography show that peak left ventricular ejection is a valuable parameter. The interpretation of the diastolic parameters is however more difficult because they are age-related.     

Left ventricular diastolic function and cardiac performance during exercise in patients with acromegaly

Exercise-induced impairment of left ventricular (LV) ejection fraction is common in patients with acromegaly and normal resting systolic function. This study aimed to clarify whether diastolic dysfunction plays a role in the abnormal adaptation to exercise in these patients. Forty-eight patients with active acromegaly underwent LV radionuclide angiography at rest and during exercise. Doppler echocardiography was also performed to assess LV mass index and diastolic function by combined analysis of mitral and pulmonary flow velocity curves. LV ejection fraction at peak exercise was related to rest ejection fraction (r = 0.78; P < 0.001), peak filling rate (r = 0.55; P < 0.01), LV mass index (r = -0.56; P < 0.001), and the difference between duration of diastolic reverse pulmonary vein flow and mitral flow at atrial contraction (Delta duration) (r = -0.54; P < 0.01). At stepwise regression analysis, rest ejection fraction and Delta duration were the only variables that independently influenced (P < 0.001) ejection fraction at peak exercise. Diastolic dysfunction is important in determining cardiac performance during exercise in patients with acromegaly and normal resting systolic function. Combined analysis of pulmonary vein and mitral flow velocity curves allows the identification of impaired LV diastolic function in such patients.     

Impaired right ventricular filling in old myocardial infarction

To evaluate ventricular filling and interactions between right and left ventricles in patients with old myocardial infarction, right and left ventricular time-volume curves were analyzed from a cineangiographic study of 10 normal subjects (Group 1), 10 patients with old anterior myocardial infarction (Group 2) and 10 patients with old inferior myocardial infarction (Group 3). Volumes of both ventricles were calculated from each frame over an entire cardiac cycle using Simpson's method. From time-volume curves, peak ejection rates, peak filling rates and atrial kick rates were obtained for both ventricles and these parameters were normalized by end-diastolic volume. All patients were in sinus rhythm with heart rates less than 80 beats/min. There were no significant differences among the 3 groups in end-diastolic pressure of both ventricles and mean pulmonary artery pressure. Left ventricular ejection fractions were significantly lower in Groups 2 and 3 than in Group 1 (p less than 0.001, p less than 0.005, respectively), although there were no significant differences in end-diastolic volume indexes of either ventricle among the 3 groups. Peak left ventricular ejection rate and peak filling rates of the left and right ventricles were lower in Group 2 than in Group 1 (p less than 0.01, p less than 0.05, p less than 0.01, respectively) and peak filling rate of the right ventricle in Group 2 correlated with the peak filling rate of the left ventricle and left ventricular ejection fraction (r = 0.64, r = 0.64, respectively). Peak filling rate of the right ventricle in Group 2 correlated inversely with left ventricular peak negative dp/dt (r = -0.72), but no correlation was found between peak filling rate of the right ventricle and left ventricular end-diastolic volume index or mean pulmonary artery pressure. Peak ejection rate of the left ventricle and peak filling rates of both ventricles in Group 3 were lower than in Group 1 (p less than 0.02, p less than 0.02, p less than 0.01, respectively) and no correlation was found between peak filling rates of both ventricles. Wall motion of the right ventricular septal portion was slightly reduced in 5 patients in Group 2. In all patients in Group 3, right ventricular wall motion centering around the right ventricular diaphragmatic portion was reduced. These results suggest that in old inferior myocardial infarction, right ventricular wall motion abnormality results in impaired right ventricular filling, whereas in old anterior myocardial infarction, right ventricular filling is reduced indirectly due to impaired left ventricular filling.     

Abnormal exercise hemodynamics in patients with normal systolic function late after aortic valve replacement

We studied the hemodynamic response to supine bicycle exercise in 20 patients late (10 +/- 2 years) after aortic valve replacement (for aortic stenosis in 12 patients, aortic insufficiency in six patients, and for combined stenosis and insufficiency in two patients). The pulmonary artery wedge pressure was obtained with a pulmonary artery balloon catheter, and left ventriculography was performed by digital-subtraction angiography after injection of radiographic contrast into the pulmonary artery. These patients were compared with 11 control subjects with no or minimal cardiac disease studied routinely for evaluation of chest pain in whom left ventricular end-diastolic pressure and a direct contrast ventriculogram were obtained. Compared with the control population, the study population had similar left heart filling pressures (7 +/- 3 vs 9 +/- 3 mm Hg, NS), but higher left ventricular ejection fractions (75 +/- 7% vs 67 +/- 7%, p less than .02) and higher left ventricular muscle mass indexes (106 +/- 28 vs 85 +/- 9 g/m2, p less than .01). Elevated myocardial muscle mass led to lower systolic wall stress in the study population than in the control subjects (254 +/- 65 vs 320 +/- 49 10(3).dynes/cm2, p less than .01) and might explain the higher ejection fraction observed. Fourteen patients had a normal response to exercise (with left heart filling pressures of 16 +/- 4 vs 18 +/- 2 mm Hg for control subjects, NS; and left ventricular ejection fraction of 77 +/- 8% vs 73 +/- 5% for control subjects, NS). However, while the remaining six patients had a normal exercise left ventricular ejection fraction (72 +/- 9%, NS), they had an abnormal rise in left heart filling pressure (33 +/- 8 mm Hg, p less than .01). Preoperatively these patients also had higher left ventricular mid- and end-diastolic pressures at similar diastolic volumes, suggesting a decrease in chamber compliance. Thus, late after aortic valve replacement there is a subgroup of patients who, despite normal hemodynamics and normal left ventricular systolic function as assessed by the left ventricular ejection fraction at rest, have an abnormal response to exercise characterized primarily by a substantial rise in left heart filling pressures. Preoperatively this group also has a decrease in diastolic chamber compliance despite nearly normal left ventricular ejection fractions. This abnormality appears to result from a primary derangement of diastolic function that is not evident at rest.     

Effects of nifedipine on left ventricular systolic and diastolic function in patients with ischemic heart disease. Radionuclide angiocardiographic studies at rest and during exercise

The purpose of this study was to evaluate the acute effects of sublingual nifedipine (10 mg) on left ventricular systolic function (ejection fraction, peak ejection rate, time to peak ejection rate) and diastolic function (peak filling rate, time to peak filling rate, filling fraction during rapid filling) at rest and during exercise using radionuclide angiography in 17 patients with ischemic heart disease. The results of the study were as follows. Diastolic indexes in the patient group were significantly different from the values in the control group at rest and during exercise. Peak filling rate and filling fraction improved significantly after nifedipine administration. These values did not show significant differences from the values in normal subjects which were obtained before nifedipine administration. The peak filling rate during exercise after nifedipine administration increased significantly, although the value was lower than that in the control group. At rest, systolic indexes in the patient group showed abnormal values, although the differences from the control values were not significant. Ejection fraction and peak ejection rate were significantly lower than those in the control group during exercise. After nifedipine administration, peak ejection rate at rest and during exercise, and ejection fraction at rest in the patient group improved significantly. Seven of 17 achieved the same exercise workloads as control conditions without symptoms or ECG changes. These data suggest that nifedipine improved left ventricular systolic and diastolic dysfunction, as well as exercise tolerance in patients with ischemic heart disease.     

Right ventricular thickness as predictor of global myocardial performance in systemic sclerosis: A Doppler tissue imaging study

Background

Cardiopulmonary involvement in systemic sclerosis (SSc) is a poor prognostic factor, due to pulmonary hypertension and right ventricular dysfunction. We assessed the echocardiographic parameters of right ventricular (RV) function in SSc and correlated echocardiographic findings to clinical features of the disease.

Methods

Thirty patients with SSc (cases) and 30 healthy, age-matched subjects (controls) were studied. Echocardiography, including tissue Doppler imaging, was used to evaluate cardiac function.

Results

Pulmonary hypertension could be documented in only 5 cases by Doppler echo, using Bernoulli principle. RV diastolic function was significantly deranged in cases. RV systolic function and left ventricle (LV) diastolic function were also significantly deranged in the cases. RV thickness was increased in patients with SSc. There were no significant differences in the echocardiographic variables between diffuse and limited subtypes of SSc. Myocardial performance index (MPI) of both ventricles were increased in cases. We could demonstrate RV thickness as the single most important predictor of MPI of both ventricles with sensitivity of 82% and specificity of 72% for RV-MPI and 63% for LV-MPI. Diastolic function was not found to be affected by disease duration or Rodnan skin score.

Conclusion

Patients with SSc exhibit abnormal RV and LV diastolic functions as well as abnormal RV systolic function. RV wall thickness was found to be simple and the single best predictor of global myocardial performance. RV dysfunction may be a response to intermittent pulmonary arterial hypertension, lung parenchymal involvement, or secondary to LV diastolic dysfunction in SSc.Abbreviations: ACE-I, angiotensin converting enzyme inhibitor; DT, deceleration time; DTI, Doppler tissue imaging; E/A ratio, early diastolic/atrial component velocity ratio; ET, ejection time; FVC, forced vital capacity; Hct, hematocrit; HRCT, high-resolution computed tomography; IVCT/ICT, isovolumic contraction time; ILD, interstitial lung disease; IVRT/IRT, isovolumic relaxation time; LV, left ventricle/ventricular; LVEDD, left ventricular end diastolic dimension; LVEDV, left ventricular end diastolic volume; LVEF, left ventricular ejection fraction; LVESD, left ventricular end systolic dimension; LVESV, left ventricular end systolic volume; MPI, myocardial performance index; PAH, pulmonary arterial hypertension; PAP, pulmonary artery pressure; PASP, pulmonary artery systolic pressure; PAT, pulmonary acceleration time; RR, electrocardiographic R–R interval; RVEF, right ventricular ejection fraction; RV, right ventricle/ventricular; SSc, systemic sclerosis     

Dobutamine stress radionuclide ventriculography reveals silent myocardial dysfunction in Kawasaki disease.

Dobutamine (DOB) stress radionuclide ventriculography (RVG) is proposed for evaluating left ventricular performance in patients with Kawasaki disease (KD). Dobutamine stress RVG, up to 15 microg x kg(-1) x min(-1), was performed in 40 patients with a history of KD, some of whom had a perfusion defect (PD group) on dipyridamole stress thallium-201 myocardial imaging, some of whom had no perfusion defects (NPD group), and some of whom had no coronary artery lesions (C group). No significant differences in either systolic or diastolic indices of the left ventricle at rest were observed between the 3 groups. Although hemodynamic responses were similar in all patients after DOB stress, early diastolic index of the first third filling fraction decreased only in the PD group and was significantly lower in this group compared with the C group (p<0.01). The asynchrony index increased significantly in those patients with coronary stenosis after DOB stress (p<0.05). No serious side-effects were observed during the study. Even late after onset, patients with myocardial ischemia as a result of KD still had impaired early diastolic filling and asynchronous relaxation of the left ventricle. As an alternative to exercise testing, DOB stress RVG is a safe and promising means for serially evaluating left ventricular performance in patients with KD.     

Improved left ventricular diastolic filling in patients with coronary artery disease after percutaneous transluminal coronary angioplasty

Left ventricular (LV) diastolic filling is abnormal at rest in many patients with coronary artery disease (CAD), even in the presence of normal resting LV systolic function. To determine the effects of improved myocardial perfusion on impaired. LV diastolic filling, we studied 25 patients with one-vessel CAD by high-temporal-resolution radionuclide angiography before and after percutaneous transluminal coronary angioplasty (PTCA). No patient had ECG evidence of previous myocardial infarction. Despite normal regional and global LV systolic function at rest in all patents, LV diastolic filling was abnormal (peak LV filling rate [PFR] less than 2.5 end-diastolic volumes (EDV)/sec or time to PFR greater than 180 msec) in 17 of 25 patients. Twenty-three patients had abnormal LV systolic function during exercise. After successful PTCA, LV ejection fraction and heart rate at rest were unchanged, but LV ejection fraction during exercise increased, from 52 +/- 8% (+/- SD) to 63 +/- 5% (p less than 0.001). LV diastolic filling at rest improved: PFR increased from 2.3 +/- 0.6 to 2.8 +/- 0.5 EDV/sec (p less than 0.001) and time to PFR decreased from 181 +/- 22 to 160 +/- 18 msec (p less than 0.001). Thus, a reduction in exercise-induced LV systolic dysfunction after PTCA, reflecting a reduction in reversible ischemia, was associated with improved LV diastolic filling at rest. These data suggest that in many CAD patients with normal resting LV systolic function and without previous infarction, abnormalities of resting LV diastolic filling are not fixed, but appear to be reversible manifestations of impaired coronary flow.     

Diastolic Dysfunction in Arterial Hypertension

Left ventricular diastolic properties are important markers of pump function and are frequently abnormal when myocardial insults alter tissue structure. Alterations can be limited to the early diastolic phase (early active relaxation) or to late diastolic filling (late ventricular compliance), but more often involve regulation of both phases of diastole. In asymptomatic patients with arterial hypertension, left ventricular relaxation is often prolonged, independently, at least in part, of cardiac loading conditions and left ventricular geometry, but this abnormality is associated with early signs of systolic dysfunction. Uncontrolled hypertension, diabetes, and obesity are most often associated with ischemic heart disease and impaired diastolic function. Reducing blood pressure with antihypertension therapy will reduce myocardial afterload, regress LVH, and improve systolic and diastolic function. In patients with symptoms of CHF with a normal ejection fraction, however, changes in therapy may be indicated. Greater emphasis should be placed on using medications that decrease myocardial load, but also reduce the effects of neurohormonal activation.     

Resting heart rate and cardiac function in dilated cardiomyopathy

We hypothesized that, within the normal range of resting heart rate, heart rate and left ventricular ejection fraction would be inversely correlated and heart rate and left ventricular filling would be correlated in patients with dilated cardiomyopathy and not correlated in patients with normal cardiac function. At rest, heart rate, left ventricular ejection fraction, and three measures of diastolic filling (time to peak filling rate, peak filling rate, and first half filling fraction) were recorded using radionuclide ventriculography in subjects with no cardiac disease, patients with idiopathic dilated cardiomyopathy, and patients with dilated cardiomyopathy associated with ischemic heart disease. Heart rate had significant inverse correlations with left ventricular ejection fraction (r=-0.55, P=0.0007) and time to peak filling rate (r=-0.47, P=0.005) and a positive correlation with peak filling rate (r=0.73, P<0.0001) in patients with idiopathic dilated cardiomyopathy; heart rate was correlated only weakly with these measures in the absence of cardiac disease and essentially was not correlated in dilated cardiomyopathy due to ischemic heart disease. The change in resting heart rate with left ventricular ejection fraction and time to peak filling rate were significantly (P<0.05) different between patients with no cardiac disease and those with idiopathic dilated cardiomyopathy. Thus, resting heart rate correlated significantly with left ventricular ejection fraction and diastolic filling in patients with idiopathic dilated cardiomyopathy.     

Dobutamine stress echocardiography in the evaluation of cardiac haemodynamics after repair of tetralogy of Fallot in children: negative effects of pulmonary regurgitation

OBJECTIVE: The aims were to evaluate right and left ventricular systolic function and pulmonary regurgitation (PR) at rest and during dobutamine stress echocardiography (DSE) and to assess relationships between PR and cardiac haemodynamics in late postoperative tetralogy of Fallot patients. METHODS AND RESULTS: Eighteen children (postoperative period 10.9 +/- 2.9 years) had heart rates, PR volumes and velocities, right ventricle (RV) volumes, ejection fraction, cardiac output and index measured at rest and during DSE. Left ventricular ejection fraction did not significantly increase and the RV volumes did not change significantly during DSE (p > 0.05). RV ejection fraction was significantly lower than that of the left ventricle at rest (p < 0.001), and patients failed to increase RV ejection fraction during DSE (p > 0.05). PR measurements increased significantly during DSE (p < 0.05). PR velocity correlated positively with RV end-diastolic volume both at rest and during DSE (p < 0.0 1). PR volume was inversely correlated with ejection fraction, cardiac output and index at rest and during DSE (p < 0.05). CONCLUSION: Latent dysfunction and impaired functional response to stress of both ventricles are detected by DSE. Although many postoperative patients are asymptomatic; assessment of postoperative haemodynamics by exercise or DSE will probably result in early detection of latent ventricular dysfunction.