Diastolic dysfunction in heart failure

Study the relationship between left atrial (LA) volume and left ventricular (LV) diastolic dysfunction and LV hypertrophy: Correlate LA volume with cardiovascular risk factors

Heart failure (HF) with normal ejection fraction - the isolated diastolic heart failure, depicts increasing prevalence and health care burden in recent times. Having less mortality rate compared to systolic heart failure but high morbidity, it is evolving as a major cardiac concern. With increasing clinical use of Left atrial volume (LAV) quantitation in clinical settings, LAV has emerged as an important independent predictor of cardiovascular outcome in HF with normal ejection fraction. This article is intended to review the diastolic and systolic heart failure, their association with left atrial volume, in depth study of Left atrial function dynamics with determinants of various functional and structural changes.

Low Calcium Dialysate Increases Cardiac Relaxation in CAPD Patients

Objective

To establish whether changes in serum calcium affect left ventricular (LV) function in continuous ambulatory peritoneal dialysis (CAPD) patients.

Methods

This study was conducted on 28 clinically stable CAPD patients (11 females, 17 males). Left ventricular relaxation and systolic function were echocardiographically examined in all patients during standard dialysate (containing 1.75 mmol/L calcium) treatment. All patients were then changed to low calcium dialysate (1.25 mmol/L calcium) for 1 month and all patients were re-examined echocardiographically. Decrement in isovolumic relaxation time (IVRT) and deceleration time (DT), and increment in the ratio of peak early to peak late diastolic velocities (E/Amax) were admitted as indexes showing improvement in LV relaxation. 17 age- and sex-matched controls were also echocardiographically examined.

Results

Deceleration time, interventricular septal thickness at systole (IVSTS) and diastole (IVSTD), and posterior wall thickness at systole (PWS) and diastole (PWD) were higher in CAPD patients using standard dialysate than in normal controls. With the use of low calcium dialysate, DTs were similar but IVSTS, IVSTD, PWS, and PWD values remained higher. In normal controls, E/Amax values were higher than those in CAPD patients using standard dialysate ( p < 0.001) and low calcium dialysate ( p = 0.009). Serum intact parathyroid hormone level, weight, clinical volume status, and blood pressure were similar throughout the study period. Serum ionized calcium levels were decreased significantly during low calcium dialysate treatment. The changes in IVRT, DT, and E/Amax suggest improvement in LV relaxation during low calcium dialysate treatment.

Conclusion

Left ventricular relaxation is increased with the use of low calcium dialysate compared with standard dialysate treatment. The idea of possible beneficial effects of increment in LV relaxation on cardiovascular morbidity and mortality deserves further studies.

Maternal Allopurinol Prevents Cardiac Dysfunction in Adult Male Offspring Programmed by Chronic Hypoxia During Pregnancy

Integrating functional and molecular levels, we investigated the effects of maternal treatment with a xanthine oxidase inhibitor on the programming of cardiac dysfunction in adult offspring using an established rat model of hypoxic pregnancy. Female Wistar rats were divided into normoxic or hypoxic (13% O₂) pregnancy±maternal allopurinol treatment (30 mg kg^-1 d^-1). At 4 months, hearts were isolated from 1 male per litter per outcome variable to determine cardiac function and responses to ischemia-reperfusion in a Langendorff preparation. Sympathetic dominance, perfusate CK (creatine kinase) and LDH (lactate dehydrogenase) and the cardiac protein expression of the β₁-adrenergic receptor, the M₂ Ach receptor (muscarinic type-2 acetylcholine receptor), and the SERCA2a (sarcoplasmic reticulum Ca²⁺ ATPase 2a) were determined. Relative to controls, offspring from hypoxic pregnancy showed elevated left ventricular end diastolic pressure (+34.7%), enhanced contractility (dP/dt_max, +41.6%), reduced coronary flow rate (-21%) and an impaired recovery to ischemia-reperfusion (left ventricular diastolic pressure, area under the curve recovery -19.1%; all P<0.05). Increased sympathetic reactivity (heart rate, +755.5%; left ventricular diastolic pressure, +418.9%) contributed to the enhanced myocardial contractility ( P<0.05). Perfusate CK (+431%) and LDH (+251.3%) and the cardiac expression of SERCA2a (+71.4%) were also elevated ( P<0.05), further linking molecular markers of cardiac stress and injury to dysfunction. Maternal allopurinol restored all functional and molecular indices of cardiac pathology. The data support a link between xanthine oxidase-derived oxidative stress in hypoxic pregnancy and cardiac dysfunction in the adult offspring, providing a target for early intervention in the developmental programming of heart disease.

Validation by Cardiac Catheterization of Noninvasive Estimation of Time Constant of Left Ventricular Pressure Decline as an Index of Relaxation by Speckle Tracking Echocardiography

There has been no established echocardiographic parameter to accurately assess left ventricular (LV) relaxation. Impaired LV relaxation assessed by the time constant of LV pressure decline (Tau) is one of the major components of diastolic dysfunction. We sought to noninvasively estimate Tau (eTau) by speckle tracking echocardiography (STE) and to validate the eTau against Tau by catheterization. Tau was reported to be calculated using the isovolumic relaxation time (IVRT), LV end-systolic pressure, and left atrial (LA) pressure. We reported that pulmonary capillary wedge pressure (ePCWP) can be noninvasively and accurately estimated as 10.8 - 12.4 × Log (LA active emptying function/minimum LA volume index). Therefore, the eTau by STE is noninvasively calculated using the formula: eTau = IVRT / (ln 0.9 × systolic blood pressure-ln ePCWP). Echocardiographic parameters were measured just before catheterization in 110 patients with cardiac disease (age 72 ± 8). There was a good correlation between the eTau and Tau by catheterization (r = 0.69, p <0.001), whereas IVRT and the e' had a poor correlation with Tau (r = 0.33 and -0.33, respectively). The sensitivity and specificity of the eTau to predict prolonged Tau (>48 ms) was 77% and 91%, respectively, with area under curve of 0.87 using an optimal cutoff of 48 ms. Bland-Altman analysis revealed a good agreement between the eTau and Tau. In conclusion, this study demonstrated that the eTau by our noninvasive method has a good correlation with Tau obtained by cardiac catheterization. LV relaxation may be noninvasively and accurately estimated by STE.

Systolic time ratio measured by impedance cardiography accurately screens left ventricular diastolic dysfunction in patients with arterial hypertension

Background

The use of impedance cardiography (ICG) may play a role in the assessment of cardiac effects of hypertension (HT), especially its hemodynamic features. Hypertensive heart disease involves structural changes and alterations in left ventricular geometry that end up causing systolic and/or diastolic dysfunction. The IMPEDDANS study aims to assess the usefulness of ICG for the screening of left ventricular diastolic dysfunction (LVDD) in patients with HT.

Methods

Patients with HT were assessed by echocardiography and ICG. Receiver-operating characteristic curve and the area under the curve were used to assess the discriminative ability of the parameters obtained by ICG to identify LVDD, as diagnosed by echocardiography.

Results

ICG derived pre-ejection period (PEP), left ventricle ejection time (LVET), systolic time ratio (STR) and D wave were associated (p < 0.001) with LVDD diagnosis, with good discriminative ability: PEP (AUC 0.81; 95% CI 0.74–0.89), LVET (AUC 0.82; 95% CI 0.75–0.88), STR (AUC 0.97; 95% CI 0.94–1.00) and presence of D wave (AUC = 0.87; 95% CI 0.82–0.93). STR ≥ 0.30 outperformed the other parameters (sensitivity of 98.0%, specificity of 90.2%, positive predictive value of 95.2%, and negative predictive value of 96.1%).

Conclusion

The ICG derived value of STR allows the accurate screening of LVDD in patients with HT. It might as well be used for follow up assessment.

Trial registration

The study protocol was retrospectively registered as IMPEDDANS on ClinicalTrials.gov (ID: NCT03209141) on July 6, 2017.

Deceleration time of left ventricular outflow tract flow as a simple surrogate marker for central haemodynamics at rest and as well as during exercise

Background

The shape and duration of left ventricular outflow tract (LVOT) flow has not been applied to assess the central haemodynamics, although LVOT flow is confronted with afterload of arterial system during systole. The aim of this study was to evaluate whether the LVOT flow parameters are related with central systolic blood pressure (BP) and arterial compliance at rest and as well as during exercise.

Methods

We studied 258 subjects (175 females, age 61 ± 11 years) with normal left ventricular (LV) systolic function who underwent supine bicycle stress echocardiography and arterial tonometry simultaneously at rest and at peak exercise. Deceleration time (DT) of LVOT flow and RR interval were measured and deceleration time corrected for heart rate (DTc) was calculated. Peripheral and central haemodynamic parameters including systolic and diastolic BP, and augmentation index at a heart rate of 75 (AIx@75) were assessed using radial artery tonometry. Carotid femoral pulse wave velocity (PWV) was measured.

ResultResults

Deceleration time corrected for heart rate was independently associated with central systolic BP and AIx@75 at rest (P < 0.001 and 0.006). Similarly, it also showed significant independent correlations with central systolic BP and AIx@75 during peak exercise (P = 0.006 and P = 0.021). In addition, DTc which measured both at rest and at peak exercise demonstrated significant positive correlations with PWV, suggesting association of prolonged DTc with arterial stiffening (P = 0.023 and P = 0.005).

Conclusion

Prolongation of LVOT flow DTc represents raised central systolic BP and increased arterial stiffness not only at rest but also during exercise. Therefore, central aortic pressures and arterial stiffness influence the DT of LVOT flow at rest as well as during exercise in individuals with normal LV systolic function.

Relationship between exercise induced dyspnea and functional capacity with doppler-derived diastolic function'

BACKGROUND

Dyspnea is the frequent cause of exercise intolerance and physical inactivity among patients referred for exercise tolerance test. Diastolic dysfunction has shown significant correlation with exercise capacity and exercise induced dyspnea. To find out the frequency of diastolic dysfunction (DD) and the relationships between impaired exercise capacity and exercise induced dyspnea with DD by Doppler-derived indices among patients referred for stress test in a tertiary care hospital of Karachi.

METHODS

For this study 135 consecutive patients who were referred for stress test at our non-invasive lab were screened for eligibility. Patients with valvular pathology, atrial fibrillation (AF) and coronary artery disease (CAD) were excluded. Stress test was performed on treadmill using Bruce protocol. Assessment of diastolic function as determined by trans-mitral flow velocity pattern was carried at baseline and at peak exercise. We evaluated impaired exercise capacity and exercise induced dyspnea using validated Borg Scale among study subjects.

RESULTS

Study subjects 88% were males, mean age was 46 ± 16 years, BMI 27 ± 5 kg/m2, prevalence of diabetes mellitus (DM) 15%, hypertension 28% and smoking 21%. Exercise induced DD occurred among 44.6%. Patients with exercise induced DD had lower exercise capacity (9.2 vs. 10.2 METS; p = 0.04) and higher Borg Scale (5.2 vs. 4.0; p < 0.001). DD at baseline was present in 25(26%) of patients so they were excluded from the study. Five patients develop ischemia during stress test so were also excluded. So final analysis was done on 105 patients. Among patients without DD at baseline, there was significant vicariate linear inverse correlation between post exercise E/A ratio and Borg scale (r = -0.23; p = 0.02) and exercise capacity was assessed by exercise duration and MET (r-0.825; p = 0.04). Multivariate regression analysis revealed post exercise E/A ratio as an independent determinant of severity of exercise induced dyspnea and impaired exercise tolerance.

CONCLUSION

DD is significantly associated with impaired functional capacity and dyspnea among patients referred for exercise tolerance test.

Concentration of natriuretic peptides in patients suffering from idiopathic arterial hypertension and left ventricular diastolic dysfunction confirmed by echocardiography

Concentration of natriuretic peptides (NPs) in arterial hypertension (AH) patients is higher than that in healthy people. One of the first symptoms of left ventricular hypertrophy (LVH) is left ventricular diastolic dysfunction (LVDD). The aim of this study was to examine whether determination of NPs in blood can be a useful indicator of LVDD detection in idiopathic AH patients. The study was conducted on three groups of patients: group Ia, 19 patients (average age 57 ± 3) with eccentric hypertrophy; group Ib, 13 patients (59 ± 4) with concentric hypertrophy; group II, 33 patients (58 ± 4) without AH or LVH. In all groups, mitral inflow profile was evaluated with Doppler test to detect LVDD, blood flow in upper right pulmonary vein, and concentration of atrial natriuretic peptide (ANP), N-terminal ANP (N-ANP), brain natriuretic peptide (BNP), and N-terminal BNP (N-BNP). In group Ia, significant correlations were observed between the following pairs: ratio of maximum early to late mitral inflow and ANP; deceleration time of early mitral inflow speed and ANP; atrial contraction (AR) and ANP; atrial contraction (AR) and N-ANP; similarly, in group Ib, significant correlations were observed between the following: relative wall thickness and BNP; isovolumic relaxation time and BNP; AR and BNP; relative wall thickness and N-BNP; isovolumic relaxation time and N-BNP; AR and N-BNP.

Vascular effects of nebivolol added to hydrochlorothiazide in African Americans with hypertension and echocardiographic evidence of diastolic dysfunction: the NASAA study

BACKGROUND

African Americans have greater risk of cardiovascular events than comparator populations of white European origin. A potential reason for this is reduced nitric oxide bioavailability in African Americans, resulting in increased prevalence of factors that contribute to ventricular dysfunction. We investigated the effects of nebivolol with the diuretic hydrochlorothiazide (HCTZ) in hypertensive African Americans with echocardiographic evidence of diastolic dysfunction.

METHODS

A total of 42 African American patients were assigned to nebivolol and HCTZ in an open-label fashion for a 24-week period. Changes in blood pressure (BP), echocardiographic parameters, and success in attaining target BP were determined. As an indirect determinant of endothelial function, serum total nitric oxide (NOx) levels and asymmetric dimethyl arginine (ADMA) levels were performed at baseline and after the treatment period.

RESULTS

The systolic BP decreased from 150 ± 13 to 136 ± 16 mm Hg (P < .005). Diastolic BP decreased from 94 ± 13 to 84 ± 9 mm Hg (P = .008). Of the patients that completed the study, 77% achieved a combined target BP of systolic BP <140 mm Hg and a diastolic BP <90 mm Hg. Serum NOx increased by 41% and 39% in patients that were treated with 10 mg and 20 mg daily nebivolol, respectively. The ADMA levels decreased by 44% following treatment. The change in systolic BP was strongly correlated to the change in ADMA (r = .54; P = .024). Furthermore, in comparison to a group of age-matched patients controlled with diuretic therapy only, the ADMA levels were significantly lower in the nebivolol posttreatment group (controlled BP with diuretic: 0.32 ± 0.07μmol/L; nebivolol posttreatment: 0.24 ± 0.06 μmol/L; P < .05).

CONCLUSION

Reduced BP with nebivolol in hypertensive African Americans and echocardiographic evidence of diastolic dysfunction correlates with improved endothelial function. Furthermore, improvement in endothelial function and increased nitric oxide bioavailability suggests a potential mechanism of efficacy of nebivolol in these patients.

Distinct effects of leukocyte and cardiac phosphoinositide 3-kinase γ activity in pressure overload-induced cardiac failure

BACKGROUND

Signaling from phosphoinositide 3-kinase γ (PI3Kγ) is crucial for leukocyte recruitment and inflammation but also contributes to cardiac maladaptive remodeling. To better understand the translational potential of these findings, this study investigates the role of PI3Kγ activity in pressure overload-induced heart failure, addressing the distinct contributions of bone marrow-derived and cardiac cells.

METHODS AND RESULTS

After transverse aortic constriction, mice knock-in for a catalytically inactive PI3Kγ (PI3Kγ KD) showed reduced fibrosis and normalized cardiac function up to 16 weeks. Accordingly, treatment with a selective PI3Kγ inhibitor prevented transverse aortic constriction-induced fibrosis. To define the cell types involved in this protection, bone marrow chimeras, lacking kinase activity in the immune system or the heart, were studied after transverse aortic constriction. Bone marrow-derived cells from PI3Kγ KD mice were not recruited to wild-type hearts, thus preventing fibrosis and preserving diastolic function. After prolonged pressure overload, chimeras with PI3Kγ KD bone marrow-derived cells showed slower development of left ventricular dilation and higher fractional shortening than controls. Conversely, in the presence of a wild-type immune system, KD hearts displayed bone marrow-derived cell infiltration and fibrosis at early stages but reduced left ventricular dilation and preserved contractile function at later time points.

CONCLUSIONS

Together, these data demonstrate that, in response to transverse aortic constriction, PI3Kγ contributes to maladaptive remodeling at multiple levels by modulating both cardiac and immune cell functions.

Left ventricular filling and diastolic myocardial deformation in chronic primary mitral regurgitation

AIMS

Chronic primary mitral regurgitation (MR) results in enhanced filling of the left ventricle (LV) during early diastole. Filling is impaired with the onset of LV systolic dysfunction, due to increased myocardial stiffness and reduced restoring forces. We investigated echocardiographic parameters of early diastolic function in relation to LV systolic function.

METHODS AND RESULTS

Early diastolic transmitral flow and tissue Doppler velocities, propagation velocity of early filling (V(p)), and early diastolic strain rates (SR-E) were measured in 30 patients with chronic degenerative MR and 30 age-matched controls. MR subjects were further subdivided into group 1 (14 subjects) if they had well compensated LV, and group 2 (16 subjects) if they had one or more of the following: functional limitation (> NYHA class I), LV end-systolic diameter >or=4.0 cm, and LV ejection fraction <or=60%. Group 1 had increased early diastolic transmitral flow and tissue velocities, V(p) and SR-E, compared with controls. V(p) and SR-E in group 2 (46.5 +/- 9.92 cm/s and 1.44 +/- 0.36 s(-1), respectively) decreased significantly compared with group 1 (74.4 +/- 19.9 cm/s and 1.96 +/- 0.53 s(-1), P <or= 0.002). Onset and peak of early long-axis expansion and myocardial lengthening were significantly delayed in MR, and this delay was directly correlated with preload parameters.

CONCLUSION

In chronic MR, novel echocardiographic measurements of early diastolic function exhibit a biphasic pattern depending on the state of LV systolic function, and may prove useful in the timing of surgery.

Nitric oxide modulates the frog heart ventricle morphodynamics

The aim of this work was to investigate in the avascular heart of the frog Rana esculenta the influence of nitric oxide (NO) on ventricular systolic and diastolic functions by using a novel image analysis technique. The external volume variations of the whole ventricle were monitored during the heart cycle by video acquisition(visible light) and analysed by an appropriately developed software with a specific formula for irregular convex solids. The system, which measures the rate of volume changes and the ejection fraction, directly determined the volumetric behaviour of the working frog heart after stimulation or inhibition of NOS-NOcGMP pathway. End-diastolic volume (EDVext), end-systolic volume (ESVext), contraction and relaxation velocities (dV/dtsys and dV/dtdia, respectively), stroke volume (SV) and ejection fraction (EF), were measured before and after perfusion with NOS substrate (L-arginine), NO donor (SIN-1), cGMP analogue (8-Br-cGMP),NOS inhibitors (NG-monomethyl-L-arginine, L-NMMA; L-N(5)-(1-iminoethyl)-ornithine, L-NIO; 7-Nitroindazole,7-NI) and guanylyl cyclase inhibitor (ODQ). The results showed that NO reduces ventricular systolicfunction improving diastolic filling, while NOS inhibition increases contractility impairing ventricular filling capacity. The presence of activated eNOS (p-eNOS) was morphologically documented, further supporting that the mechanical activity of the ventricular pump in frog is influenced by a tonic release of NOS-generated NO.

Systolic and diastolic heart failure: Different phenotypes of the same disease?

Traditional pathophysiological concepts of chronic heart failure have largely focused on the haemodynamic consequences of ventricular systolic dysfunction. How these concepts relate to the pathophysiology of diastolic heart failure, i.e., heart failure with a preserved ejection fraction is, however, unclear, causing uncertainty about pathophysiology, diagnosis and management. Recent measurements of regional myocardial systolic function in patients with diastolic heart failure indicate that systolic and diastolic heart failure may be more closely related than previously anticipated. Rather than being considered as separate diseases with a distinct pathophysiology, systolic and diastolic heart failure may be merely different clinical presentations within a phenotypic spectrum of one and the same disease. In this review, we will interpret these new insights in a broader conceptual context of chronic heart failure and design novel paradigms in which systolic and diastolic heart failure jointly progress in a pathophysiological time trajectory of only one disease.

Cardiac Dysfunction in Heart Failure: The Cardiologist's Love Affair with Time

Translating research into clinical practice has been a challenge throughout medical history. From the present review, it should be clear that this is particularly the case for heart failure. As a consequence, public awareness of this disease has been disillusionedly low, despite its prognosis being worse than that of most cancers and many other chronic diseases. We explore how over the past 150 years since Ludwig and Marey concepts about the evaluation of cardiac performance in patients with heart failure have emerged. From this historical-physiologic perspective, we have seen how 3 increasingly reductionist approaches or schools of thought have evolved in parallel, that is, an input-output approach, a hemodynamic pump approach, and a muscular pump approach. Each one of these has provided complementary insights into the pathophysiology of heart failure and has resulted in measurements or derived indices, some of which still being in use in present-day cardiology. From the third, most reductionist muscular pump approach, we have learned that myocardial and ventricular relaxation properties as well as temporal and spatial nonuniformities have been largely overlooked in the 2 other, input-output and hemodynamic pump, approaches. A key message from the present review is that relaxation and nonuniformities can be fully understood only from within the time-space continuum of cardiac pumping. As cyclicity and rhythm are, in some way, the most basic aspects of cardiac function, considerations of time should dominate over any measurement of cardiac performance as a muscular pump. Any measurement that is blind for the arrow of cardiac time should therefore be interpreted with caution. We have seen how the escape from the time domain-as with the calculation of LV ejection fraction-fascinating though as it may be, has undoubtedly served to hinder a rational scientific debate on the recent, so-called systolic-diastolic heart failure controversy. Lacking appreciation of early relaxation abnormalities and inappropriate degrees of nonuniformities has, indeed, led to some unfortunate misunderstandings about the pathophysiologic time progression of heart failure, in particular, heart failure with compensated hemodynamic pump function (ie, with normal or preserved LV ejection fraction). We have seen that with the introduction of newer powerful diagnostic techniques, as, for example, TDI and MRI, to evaluate ventricular "muscular pump" function, this debate can now be held in a more serene physiologic context. These aspects will be elaborated further in subsequent chapter papers of this symposium. With ongoing stem and other cell-based therapies and future reductionistic insights into cardiac cellular performance, we foresee the emergence of a fourth simple-parallel school of thought viewing the heart as a network of communicating different cell types, that is, cardiomyocytes, endothelial cells, fibroblasts, neurons. In this postgenomic age with the introduction of the rapidly evolving discipline of in vivo molecular imaging techniques, we anticipate that novel measurements of cardiac performance in patients with heart failure will soon become available and complement biopsy and other already available cardiac cellular biomarkers (cardiac troponin I; creatine kinase-MB; myoglobin; BNP). Through the use of these novel biomarkers as a fourth diagnostic track in the evaluation of cardiac performance in patients with heart failure, we will soon be able to increasingly understand the behavior of the heart as a complex biologic system-in other words, how these "low-level" biologic functions and signal transduction pathways at a cellular level contribute to the above "high-level" or system-level approach of cardiac performance at the muscular, the hemodynamic, and the input-output pump system levels and, hopefully, how they could contribute to an early diagnosis of chronic heart failure, in patients.

Prolonged mechanical systole and increased arterial wave reflections in diastolic dysfunction

OBJECTIVE

To evaluate whether left ventricular ejection time indexed for heart rate (left ventricular ejection time index (LVETI)) and arterial wave reflections (augmented pressure (AP)) are increased in patients with diastolic dysfunction (DD).

DESIGN

Prospective observational study.

SETTING

University teaching hospital providing primary and tertiary care.

SUBJECTS

235 consecutive patients undergoing left heart catheterisation were categorised as having definite DD, possible DD or no DD (controls) on the basis of their left ventricular end diastolic pressures and N-terminal brain natriuretic peptide concentrations.

MAIN OUTCOME MEASURES

LVETI and AP were prospectively assessed non-invasively by radial applanation tonometry. In addition, all patients underwent comprehensive echocardiography, including tissue Doppler imaging of mitral annulus velocity in early diastole (E').

RESULTS

LVETI was longer in patients with definite DD than in patients with possible DD and in controls (433.6 (SD 17.2), 425.9 (17.9) and 414.3 (13.6) ms, respectively, p < 0.000001). Arterial wave reflections were higher in definite DD than in possible DD and control groups (AP was 19.4 (SD 8.9), 15.2 (8.0) and 10.7 (6.8) mm Hg, respectively, p < 0.000001). In receiver operating characteristic curve analysis, LVETI detected DD as well as echocardiography (E:E'). Area under the curve for LVETI to differentiate patients with definite DD from normal controls was 0.81 (95% CI 0.72 to 0.89, p < 0.0001). In multivariable logistic regression analysis, LVETI added significant independent power to clinical and echocardiographic variables for prediction of DD.

CONCLUSIONS

Mechanical systole is prolonged and arterial wave reflections are increased in most patients with DD. Rapid non-invasive assessment of these parameters may aid in confirming or excluding DD.

Lack of inertia force of late systolic aortic flow is a cause of left ventricular isolated diastolic dysfunction in patients with coronary artery disease

OBJECTIVES

We investigated whether a lack of inertia force of late systolic aortic flow and/or apical asynergy provoke early diastolic dysfunction in patients with coronary artery disease (CAD).

BACKGROUND

Left ventricular (LV) isolated diastolic dysfunction is a well-recognized cause of heart failure.

METHODS

We evaluated LV apical wall motion and obtained left ventricular ejection fraction (LVEF) by left ventriculography in 101 patients who underwent cardiac catheterization to assess CAD. We also computed the LV relaxation time constant (Tp) and the inertia force of late systolic aortic flow from the LV pressure (P)-first derivative of left ventricular pressure (dP/dt) relation. Using color Doppler echocardiography, we measured the propagation velocity of LV early diastolic filling flow (Vp). Patients with LVEF > or =50% (preserved systolic function [PSF], n = 83) were divided into 2 subgroups: patients with inertia force (n = 53) and without inertia force (n = 30). No patient with systolic dysfunction (SDF) (LVEF <50%) had inertia force (n = 18).

RESULTS

The Tp was significantly longer in patients with SDF (85.7 +/- 21.0 ms) and with PSF without inertia force (81.1 +/- 23.6 ms) than in those with PSF with inertia force (66.3 +/- 12.8 ms) (p< 0.001). The Vp was significantly less in the former 2 groups than in the last group. In patients with PSF, LV apical wall motion abnormality was less frequently observed in those with inertia force than in those without (p < 0.0001).

CONCLUSIONS

An absence of inertia force in patients with PSF is one of the causes of isolated diastolic dysfunction in patients with CAD. Normal LV apical wall motion is substantial enough to give inertia to late systolic aortic flow.

Relationship between insulin resistance and left ventricular diastolic dysfunction in patients with impaired glucose tolerance and type 2 diabetes

AIM

The aim of this study was to explore the relationship between insulin resistance (IR) and the left ventricular diastolic function in patients with type 2 diabetes and subjects with impaired glucose tolerance (IGT).

METHODS

The study included 119 subjects who underwent oral glucose tolerance test (OGTT). IR was assessed using Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) and Quantitative Insulin Sensitivity Check Index (QUICKI). Left ventricular diastolic function was assessed using trans-thoracic Doppler echocardiography.

RESULTS

Based on the OGTT results, 29 subjects had normal glucose tolerance (NGT), 20 subjects had impaired glucose tolerance (IGT), and 70 patients had type 2 diabetes. There were significant differences among the patients in groups with NGT, IGT and diabetes regarding HOMA-IR (4.20 +/- 1.20 vs. 6.45 +/- 3.83 vs. 8.70 +/- 6.26; P < 0.001) and QUICKI (0.54 +/- 0.11 vs. 0.49 +/- 0.08 vs. 0.47 +/- 0.08; P < 0.001). In subjects with NGT, IGT and patients with diabetes, the pulsed Doppler transmitral variables were: E-wave (0.72 +/- 0.16 cm/s vs. 0.62 +/- 0.13 cm/s vs. 0.58 +/- 0.17 cm/s; P < 0.001), A-wave (0.61 +/- 0.13 cm/s vs. 0.62 +/- 0.11 cm/s vs. 0.71+/- 0.14 cm/s; P = 0.006) and E/A ratio (1.22 +/- 0.33 vs. 1.02 +/- 0.24 vs. 0.85 +/- 0.26; p < 0.001). The proportion of subjects with an E/A ratio <1 was 27.6% in the group with NGT, 55% in the group with IGT and 75.7% in the group with diabetes (P < 0.001). The E/A ratio correlated with HOMA-IR (r = -0.30, p = 0.001) and QUICKI (r = 0.37, p < 0.0001). Multiple linear regression model showed that IR (assessed by QUICKI) was an independent correlate of diastolic dysfunction (P = 0.034).

CONCLUSIONS

In subjects with impaired glucose tolerance and patients with type 2 diabetes, insulin resistance is associated with impaired diastolic function of the left ventricle.

Diastolic heart failure: a myth

PURPOSE OF REVIEW

Until recently, patients with heart failure and preserved ejection fraction (HFprEF) have been excluded from nearly all large clinical trials in heart failure. Based on the conjecture that this clinical picture of heart failure, also known as diastolic heart failure, may be different from other forms of heart failure, several recent and ongoing clinical trials have targeted more specifically this patient population. The present review critically re-evaluates the pathophysiological rationale for such trials.

RECENT FINDINGS

Novel techniques to evaluate cardiac performance have revealed that HFprEF is a consequence of significant systolic dysfunction of the ventricular muscular pump in the presence of a preserved performance of the ventricular hemodynamic pump. Diastolic and systolic heart failure are the mere extremes of a spectrum of different phenotypes of one and the same disease. Ongoing research explores the various disease modifiers, or protective pathways, that delay the progression of remodeling in patients with HFprEF. Although, currently, therapy to improve the prognosis of HFprEF is essentially the same as for other forms of heart failure, the latter ongoing studies may help, in addition, in developing novel and more patient-specific therapeutic strategies in these patients.

SUMMARY

HFprEF constitutes a heterogenous group of different phenotypes within one continuous spectrum reflecting heart failure as one disease entity. No pathophysiological basis currently warrants setting up empirical clinical trials based on an arbitrary subdivision of patients with heart failure.

Ransacking the curve of cardiac isovolumic pressure decay by logistic-and-oscillation regression

The decelerative part of the left ventricular isovolumic pressure decay is an important phase to make the heart ready for diastolic refill (lusitropy). Its widely used characterization by an exponential regression with zero pressure asymptote or coestimated asymptote provides empirically biased time constant estimates because of significant deviations of the pressure decay from exponentiality. We systematically analyzed the regression residua of these pressure decays in isolated ejecting rat, guinea pig, and ferret hearts. A four-parametric logistic (tangens hyperbolicus) function, together with a superimposed acustomechanic oscillation, yields normally distributed residua with standard regression error typically less than one per cent of the initial pressure; this is the first model with proved unbiased and statistically complete regressive extraction of the information provided by the time course of pressure decay. Equal values of the lusitropic parameters (logistic time constant and pressure asymptote) were estimated even after the oscillatory component was removed from the regression model. Reliable estimates of the frequency, but not of the amplitude, can be obtained by fitting the oscillation model to the residua provided by the logistic; this two-step method is statistically weaker than the full one-step model, but it reduces computational effort. In conclusion, the four-parametric logistic, but not a three-parametric exponential or logistic model, suffices to obtain unbiased lusitropic parameters characterizing the left ventricular isovolumic pressure decay of small animal hearts.

Role of Diastole in Left Ventricular Function, I: Biochemical and Biomechanical Events

Left ventricular diastolic function plays an important role in cardiac physiology. Lusitropy, the ability of the cardiac myocytes to relax, is affected by both biochemical events within the myocyte and biomechanical events in the left ventricle. β-Adrenergic stimulation alters diastole by enhancing the phosphorylation of phospholamban, a substrate within the myocyte that increases the uptake of calcium ions into the sarcoplasmic reticulum, increasing the rate of relaxation. Troponin I, a regulatory protein involved in the coupling of excitation to contraction, is vital to maintaining the diastolic state; depletion of troponin I can produce diastolic dysfunction. Other biochemical events, such as defects in the voltage-sensitive release mechanism or in inositol triphosphate calcium release channels, have also been implicated in altering diastolic tone. Extracellular collagen determines myocardial stiffness; impaired glucose tolerance can induce an increase in collagen cross-linking and lead to higher end-diastolic pressures. The passive properties of the left ventricle are most accurately measured during the diastasis and atrial contraction phases of diastole. These phases of the cardiac cycle are the least affected by volume status, afterload, inherent viscoelasticity, and the inotropic state of the myocardium. Diastolic abnormalities can be conceptualized by using pressure-volume loops that illustrate myocardial work and both diastolic and systolic pressure-volume relationships. The pressure-volume model is an educational tool that can be used to demonstrate isolated changes in preload, afterload, inotropy, and lusitropy and their interaction.

Predictors of mortality in patients with heart failure and preserved systolic function in the Digitalis Investigation Group trial

OBJECTIVES

We identified predictors of mortality in patients with preserved ejection fraction (EF) and clinical heart failure (HF).

BACKGROUND

Although diastolic HF is common, the factors that predict mortality have not been clearly defined.

METHODS

We studied 988 patients with HF and preserved EF enrolled in the Digitalis Investigation Group (DIG) trial. Survival analyses were employed to identify variables associated with mortality.

RESULTS

During 3.1 years of follow-up, 231 (23%) patients died. Among 18 variables considered, the strongest independent predictors of death were glomerular filtration rate (adjusted hazard ratio for one standard deviation decrease 1.50, 95% confidence interval [CI] 1.35 to 1.67, p < 0.0001), New York Heart Association functional class III or IV (adjusted hazard ratio 1.64, 95% CI 1.20 to 2.18, p = 0.0011), male gender (adjusted hazard ratio 1.71, 95% CI 1.26 to 2.32, p = 0.0005), and older age (adjusted hazard ratio for one standard deviation increase of age2 1.28, 95% CI 1.08 to 1.50, p = 0.0019). A risk score was developed to estimate long-term mortality.

CONCLUSIONS

Diastolic HF is associated with a high death rate. Important predictors of death include impaired renal function, worse functional class, male gender, and older age.

New insights into diastolic heart failure: role of diabetes mellitus

Heart failure affects nearly 5 million people in the United States and is a major contributor to mortality, hospitalization, and medical costs. Approximately 40% of patients with heart failure have preserved left ventricular systolic function, thus exhibiting diastolic heart failure. More common in women and the elderly, this condition is associated with hypertension, coronary artery disease, and/or atrial fibrillation. With the exception of the Digitalis Investigation Group (DIG) and the Candesartin in Heart Failure: Assessment of Reduction in Mortality and Morbidity (CHARM)-Preserved trials, no completed large randomized clinical trial has addressed the management of such patients. Symptomatic treatment involves administration of diuretics and nitrates, but long-term management with angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, aldosterone antagonists, beta-blockers, and calcium channel blockers targets the underlying disorders. Recent studies found that diabetes mellitus produces functional, biochemical, and morphologic myocardial abnormalities independent of coronary atherosclerosis and hypertension. These abnormalities may result in impaired left ventricular diastolic function, contributing importantly to heart failure with normal systolic function. Although tight glycemic control decreases the risk of heart failure in patients with diabetes, the effects of different diabetic treatment regimens on heart failure with normal systolic function are unknown and remain subject to future investigation.

Cycling cross-bridges increase myocardial stiffness at submaximal levels of Ca2+ activation

Permeabilized multicellular preparations of canine myocardium were subjected to controlled length changes to investigate the extent to which cross-bridges augment passive stiffness components in myocardium at low levels of Ca(2+) activation. When the preparations were immersed in pCa 9.0 solution (negligible free [Ca(2+)]) they behaved as simple elastic systems (i.e., tension increased proportionately with length). In contrast, when the muscles were stretched in Ca(2+) activating solutions, tension rose much more rapidly during the initial phase of the movement than thereafter. Several lines of evidence suggest that the nonlinear response represents the displacement of populations of cycling cross-bridges that are perturbed by interfilamentary movement and take some time to recover. 1), The stiffness of the initial phase increased proportionately with the level of Ca(2+) activation. 2), The magnitude of the short-range response increased with stretch velocity. 3), The initial response was reversibly reduced by 5-mM 2,3-butanedione monoxime, a known cross-bridge inhibitor. The initial stiffness of the passive elastic (pCa 9.0) response was equivalent to the Ca(2+) dependent component at 2% (pCa approximately 6.2) of the maximal (pCa 4.5) level. These results suggest that cross-bridges may significantly affect diastolic chamber stiffness.

Cardiac endothelial-myocardial signaling: its role in cardiac growth, contractile performance, and rhythmicity

Experimental work during the past 15 years has demonstrated that endothelial cells in the heart play an obligatory role in regulating and maintaining cardiac function, in particular, at the endocardium and in the myocardial capillaries where endothelial cells directly interact with adjacent cardiomyocytes. The emerging field of targeted gene manipulation has led to the contention that cardiac endothelial-cardiomyocytal interaction is a prerequisite for normal cardiac development and growth. Some of the molecular mechanisms and cellular signals governing this interaction, such as neuregulin, vascular endothelial growth factor, and angiopoietin, continue to maintain phenotype and survival of cardiomyocytes in the adult heart. Cardiac endothelial cells, like vascular endothelial cells, also express and release a variety of auto- and paracrine agents, such as nitric oxide, endothelin, prostaglandin I(2), and angiotensin II, which directly influence cardiac metabolism, growth, contractile performance, and rhythmicity of the adult heart. The synthesis, secretion, and, most importantly, the activities of these endothelium-derived substances in the heart are closely linked, interrelated, and interactive. It may therefore be simplistic to try and define their properties independently from one another. Moreover, in relation specifically to the endocardial endothelium, an active transendothelial physicochemical gradient for various ions, or blood-heart barrier, has been demonstrated. Linkage of this blood-heart barrier to the various other endothelium-mediated signaling pathways or to the putative vascular endothelium-derived hyperpolarizing factors remains to be determined. At the early stages of cardiac failure, all major cardiovascular risk factors may cause cardiac endothelial activation as an adaptive response often followed by cardiac endothelial dysfunction. Because of the interdependency of all endothelial signaling pathways, activation or disturbance of any will necessarily affect the others leading to a disturbance of their normal balance, leading to further progression of cardiac failure.

Echo-Doppler mitral flow monitoring: an operative tool to evaluate day-to-day tolerance to and effectiveness of beta-adrenergic blocking agent therapy in patients with chronic heart failure

OBJECTIVES

The goals of this study were: 1) to assess the predictive value of baseline mitral flow pattern (MFP) and its changes after loading manipulations as regards tolerance to and effectiveness of beta-adrenergic blocking agent treatment in patients with chronic heart failure (CHF); and 2) to analyze the prognostic implications of chronic MFP modifications after beta-blocker treatment.

BACKGROUND

In patients with CHF, carvedilol therapy induces clinical and hemodynamic improvements. Individual management, clinical effectiveness and prognostic implications, however, remain unclear. The MFP changes induced by loading manipulations provide independent prognostic information.

METHODS

Echo-Doppler was performed at baseline and after loading manipulations in 116 consecutive patients with CHF (left ventricular ejection fraction: 25 +/- 7%); 54 patients with a baseline restrictive MFP were given nitroprusside infusion; 62 patients with a baseline nonrestrictive MFP performed passive leg lifting. According to changes in MFP, we identified four groups: 17 with irreversible restrictive MFP (Irr-rMFP), 37 with reversible restrictive MFP (Rev-rMFP), 12 with unstable nonrestrictive MFP (Un-nrMFP) and 50 with stable nonrestrictive MFP (Sta-nrMFP). Carvedilol therapy (44 +/- 27 mg) was administered blind to results of loading maneuvers. After six months, MFP was reassessed and patients reclassified according to chronic MFP changes. During follow-up, tolerance to and effectiveness of treatment and major cardiac events (death, readmission and urgent transplantation) were considered.

RESULTS

Changes of MFP after loading manipulations were more accurate than baseline MFP in predicting both tolerance to (p < 0.01) and effectiveness of (p < 0.05) carvedilol. After 26 +/- 14 months of follow-up, cardiac events had occurred in 23/102 patients (23%). The event rate in patients with chronic Irr-rMFP or Un-nrMFP was markedly higher than it was in those with Rev-rMFP or Sta-nrMFP.

CONCLUSIONS

In our patients, tolerance to and effectiveness of carvedilol was predicted better by echo-Doppler MFP changes after loading manipulations than by baseline MFP. Chronic changes of MFP after therapy are strong predictors of major cardiac events.

Approach to patients with heart failure and normal ejection fraction

Approximately 50% of patients with a firm clinical diagnosis of heart failure (HF) have a normal ejection fraction. Some patients have valvular disease, but most have underlying diastolic dysfunction that leads to pulmonary and systemic congestion and signs and symptoms of HF. Although diastolic HF is clinically and radiographically indistinguishable from HF with depressed left systolic ventricular function, knowledge of which patients are at risk of diastolic HF, the common clinical profiles, and the common echocardiographic findings enhances the clinician's ability to diagnose diastolic HF with confidence. The prognostic implications of a diagnosis of diastolic HF and the therapeutic approach to such patients are reviewed.

Diastolic heart failure in the community

Although it is now widely recognized that isolated diastolic dysfunction can lead to the classic signs and symptoms of congestive heart failure (CHF), this disease process is poorly understood and remains of great interest and concern to cardiovascular disease specialists, as well as to primary care physicians. Recent epidemiologic data have suggested that diastolic heart failure is predominantly a disease of the elderly, the fastest growing segment of our population. Diagnosis is often difficult in this subgroup of patients due to the presence of confounding comorbidities. However, early identification in community-based practices and timely intervention is important due to the significant disability and death that results from this progressive disease process. The poor prognosis of CHF patients with systolic dysfunction is shared by those with isolated diastolic heart failure and preserved systolic function. Further studies of the prevalence, clinical characteristics, and natural history of patients with diastolic dysfunction are needed. This review focuses on the emerging data regarding the prevalence and natural history of diastolic heart failure in the community.

Molecular aspects and gene therapy prospects for diastolic failure

Because of safety issues, components of the beta-adrenergic signaling pathway cannot currently be viewed as attractive targets for human gene therapy. Rather, the balance of evidence supports strategies that will target gene products specifically and directly at diastolic regulation. Augmenting the activity of the SR Ca2+ ATPase by AAV-mediated delivery of the SERCA2a gene, directed by a cardiac-specific promoter with a tightly regulable on-off switch is perhaps the most attractive strategy. PLB and cTnI also are attractive targets but only if molecular techniques can be devised to modulate their activity specifically and conditionally. Such techniques may involve modifying the phosphorylation sites in vitro and replacing wild type proteins in the failing heart with the modified forms, again using regulated AAV vectors for gene delivery.

Diagnosis and treatment of diastolic heart failure

Up to 40% of patients with heart failure have isolated diastolic dysfunction. With proper management, the prognosis is generally more favorable than in systolic dysfunction. Distinguishing diastolic from systolic dysfunction is essential since the optimal therapy for one condition may aggravate the other. New echocardiographic methods enable accurate diagnoses.

Hemodialysis with high-calcium dialysate impairs cardiac relaxation

BACKGROUND

During hemodialysis (HD), serum ionized calcium is directly related to the dialysate calcium concentration. We have recently shown an acute induction of hypercalcemia to impair left ventricular (LV) relaxation. In the current study we sought to establish whether changes in serum Ca++ also affect LV function during HD.

METHODS

We echocardiographically examined the LV relaxation and systolic function of 12 patients with end-stage renal disease before and after three HD treatments with dialysate Ca++ concentrations of 1.25 mmol/liter (dCa++1.25), 1.5 mmol/liter (dCa++1.50), and 1.75 mmol/liter (dCa++1.75), respectively. Age- and sex-matched healthy controls were also examined echocardiographically.

RESULTS

The LV posterior wall thickness and the interventricular septum thickness, and the LV end-diastolic dimension and the end-systolic dimensions were significantly greater in the patients when compared with the controls, and the LV fractional shortening, the ratio of peak early to peak late diastolic velocities (E/Amax), and the isovolumic relaxation time (IVRT) showed impairment of LV relaxation and systolic function in the patients. Serum ionized calcium increased significantly during the dCa++1.5 HD (1.24 +/- 0.10 vs. 1.34 +/- 0.06 mmol/liter, P = 0. 004) and dCa++1.75 HD (1.19 +/- 0.10 vs. 1.47 +/- 0.06 mmol/liter, P = 0.002), and plasma intact parathyroid hormone decreased significantly during the dCa++1.75 HD (medians 8.2 vs. 2.7 pmol/liter, P = 0.002). LV systolic function was not altered during any of the treatments. The changes in E/Amax and IVRT suggested impairment of relaxation during all sessions, but only during the dCa++1.75 HD was the impairment statistically significant (E/Amax 1. 153 +/- 0.437 vs. 0.943 +/- 0.352, P < 0.05; IVRT 147 +/- 29 vs. 175 +/- 50 msecond, P < 0.05).

CONCLUSION

HD with high-calcium (dCa++1. 75 mmol/liter) dialysate impairs LV relaxation when compared with lower calcium dialysate (dCa++1.25 and dCa++1.5 mmol/liter) treatments.