|
|
||||||||
REVIEW ARTICLE |
From Temple University Hospital in Philadelphia, Pa., Gilbert E. D'Alonzo, Jr, DO, is the editor in chief of JAOA—The Journal of the American Osteopathic Association.
Address correspondence to Sunil Dhar, MD, Temple University Hospital-Episcopal Campus, 100 E Lehigh Ave, Philadelphia, PA 19125-1012. E-mail: dharsk{at}tuhs.temple.edu
Heart failure is a highly prevalent condition, particularly among elderly adults and women. In diastolic heart failure—or heart failure with normal ejection fraction—left ventricular systolic function is preserved. Although diastolic heart failure is clinically and radiographically indistinguishable from systolic heart failure, echocardiography can reveal a preserved ejection fraction with abnormal diastolic function. The present article reviews current medical concepts related to diastolic heart failure for medical practitioners, particularly primary care physicians, who play a vital role in the care of patients with heart failure. Treatment options, focusing on calcium channel blockers and angiotensin receptor blockers, are discussed. With early diagnosis and proper management, the prognosis of diastolic heart failure can be more favorable than that of systolic heart failure.
Diastolic heart failure is most common in elderly patients and women with a history of essential hypertension, ventricular hypertrophy, diabetes, and cardiac ischemia.2 As a result of the condition, mortality, morbidity, and healthcare costs are high.3 Although DHF typically has a lower in-hospital mortality rate than systolic heart failure, hospitalization frequency for both conditions is comparable.4,5
For the current article, the authors searched Elsevier's EMBASE and MD Consult databases as well as the US National Library of Medicine's PubMed database through February 2007 for articles that focus on diastolic dysfunction. Key words and phrases searched consisted of "left ventricular diastolic dysfunction," "heart failure," and "heart failure with normal ejection fraction." The authors present a review of several aspects of DHF and provide recommendations and guidelines for the diagnosis, treatment, and prognosis of this condition.
| Epidemiology |
|---|
|
|
|---|
| Pathophysiology |
|---|
|
|
|---|
Patients with DHF have a preserved ejection fraction despite increased LV diastolic pressure and pulmonary venous pressure. These patients have both increased passive stiffness and abnormal active relaxation of the left ventricle, which may work independently to cause abnormal diastolic physiology.13 This effect has been suggested by showing that even after correction for slow relaxation, increased passive stiffness was found to be an important factor in LV diastolic dysfunction and DHF.13 Under such conditions, the left ventricle typically cannot fill to the minimal volume without elevating diastolic pressures, eventually leading to pulmonary congestion, which in turn leads to DHF.14-16
Ventricular relaxation, as an energy-dependent process, may be impaired by decreased availability of adenosine triphosphate (ATP) and changes in calcium metabolism.14,17 Remova of calcium from the cytosol may be delayed by a decrease in the activity of sarco/endoplasmic reticulum calcium adenosine triphotphase (SERCA) or an increase in the level of activity of phospholamban, which is a SERCA-inhibitory protein.14,18,19 Pathologic ventricular hypertrophy, secondary to hypertension or aortic stenosis, with impaired relaxation of the ventricular muscle leads to a decrease in SERCA levels. Similar changes are seen in the myocardium of patients with hypertrophic or dilated cardiomyopathy. One animal study20 showed that the calcium pump rate in the sarcoplasmic reticulum is diminished in the hearts of senescent rats compared with younger rats. Levels of SERCA are also known to decrease with age. Older hearts have degenerative changes in the myocardium and reduced β-adrenergic tone.21 These changes might explain the disorder's prevalence in elderly patients.
However, despite these studies, some evidence suggests that the estimated end-diastolic pressure-volume relationship in a subgroup of hypertensive patients who have DHF with seemingly small hearts is normal and not consistent with the DHF paradigm as discussed in the preceding paragraphs.22
Myocardial Ischemia
One of the most common cardiac diseases associated with abnormal LV
diastolic function is myocardial ischemia. The slowing or failure of myocyte
relaxation causes a fraction of actin-myosin crossbridges to continue to
generate tension throughout diastole—especially in early
diastole—creating a state of "partial persistent systole."
Two kinds of ischemia can alter diastolic function: (1) demand ischemia,
created by an increase in energy use and oxygen demand that outweighs the
necessary myocardial supply, and (2) supply ischemia, caused by a decrease in
myocardial blood flow and oxygen demand without a change in energy use.
During demand ischemia, diastolic dysfunction may be related to myocardial ATP depletion with a concomitant increase in adenosine diphosphate, resulting in rigor bond formation.23 Consequently, LV pressure decay is impaired and the left ventricle is stiffer than normal during diastole. Although ischemia is also associated with persistence of an increased intracellular calcium concentration during diastole, it is not clear if elevated calcium levels contribute directly to diastolic dysfunction.23
Supply ischemia results from a marked reduction in coronary flow. The net effect is inadequate coronary perfusion even in the resting state. Acute supply ischemia causes an initial transient downward and rightward shift of the diastolic pressure-volume curve such that end-diastolic volume increases relative to end-diastolic pressure, creating a "paradoxical" increase in diastolic compliance.24 By contrast, diastolic compliance substantially falls during demand ischemia.25,26
These opposite initial compliance changes with demand and supply ischemia may be explained by differences in pressure and volume within the coronary vasculature, by the mechanical effects of the normal myocardium adjacent to the ischemic region, and by tissue metabolic factors. However, the differences between supply and demand ischemia are transient: after more than 30 minutes of sustained ischemia, both types of ischemia result in decreased diastolic compliance.25,26
Renin-Angiotensin-Aldosterone System
Activation of the renin-angiotensin-aldosterone system is a key factor in
the eventual development of myocardial fibrosis and wall stiffness. Besides
stimulating vasoconstriction and salt and water retention, angiotensin II
increases collagen
deposition.27 Types
I and III collagen are the major types present in the myocardium in both
normal and diseased myocardial tissue. Fibrillar collagens within the
myocardium are important substrates for matrix metalloproteinases (MMPs). The
actual activity of MMP, a tightly regulated process, depends on the rate of
synthesis, activation, and balance between active enzymes and inhibitors.
Angiotensin II stimulates collagen synthesis and regulates collagen
degradation by attenuating interstitial metalloproteinase 1 (MMP-1) activity
and by enhancing production of the tissue inhibitor of MMP-1 in endothelial
cells.28-30
However, excessive deposition of collagen may be responsible for abnormal
tissue stiffness and altered cardiac function during
hypertrophy—particularly the chronic phase—and heart failure.
When establishing the pathophysiology during the chronic phase of hypertrophy and heart failure, the quality of the collagen is more important than the quantity of collagen. Collagen quality, which is determined by the type I/type III ratio of collagen, can help predict heart muscle stiffness.31 Based on experiments performed on isolated fibroblasts, angiotensin II can directly activate collagen synthesis, while endothelin-1 increases both collagen synthesis and cardiac fibroblast proliferation and reduces collagenolytic activity.32,33 Aldosterone, a mineralocorticoid, stimulates collagen deposition and sodium retention.27 All of these changes in the extracellular matrix, particularly in fibrillar collagen, contribute to ventricular hypertrophy, diastolic stiffness, and eventually DHF.14
Pulmonary Diseases
In patients who have lung diseases with respiratory failure—most
notably patients with chronic obstructive pulmonary disease
(COPD)—pulmonary hypertension and right ventricular dysfunction can
develop. Such development has been attributed to increased right ventricular
afterload because of pulmonary
hypertension.34,35
However, patients who have COPD and respiratory failure may also have LV
diastolic
dysfunction.36 For
example, a right ventricular pressure overload may cause a leftward
displacement of the interventricular septum, which in turn may cause LV
diastolic
dysfunction.37
However, in a dog model with pulmonary emphysema and hypoxia, LV diastolic
dysfunction was present without septum
bowing.38 This
finding suggests that intrinsic mechanisms in the LV myocardium participate in
LV diastolic
dysfunction.38
There are many other causes of alveolar hypoxia that are responsible for right ventricular failure and LV diastolic dysfunction, such as obstructive sleep apnea (OSA) with or without obesity hypoventilation. Many obese patients with OSA also have essential hypertension and diabetes, placing them at increased risk for DHF. Currently, the pathophysiologic mechanisms linking OSA with diastolic dysfunction and DHF are not clearly understood. One explanation is that elevations in nocturnal blood pressure and sympathetic nervous system activity in patients who have OSA create ventricular pressure overload.39,40 It is speculated that, as DHF occurs in patients who have other diseases, such as chronic hypertension and aortic stenosis, increased pressure overload at the cellular level results in decreased levels of SERCA and increased levels of phospholamban.41 As stated earlier, increased pressure slows the removal of calcium from the cytosol, leading to impaired ventricular relaxation. In an experimental study,42 ventricular pressure overload impaired myocardial relaxation. Concurrently, pressure overload causes activation of multiple cellular signals that create myocardial tissue hypertrophy and interstitial fibrosis, both of which increase passive stiffness.43 In addition, impaired coronary flow reserve, which causes silent ischemia, worsens ventricular active relaxation when LV diastolic pressure begins to rise.
Another possible mechanism to explain the presence of diastolic dysfunction in patients who have pulmonary diseases relates to futile inspiratory efforts. Such efforts result in elevated negative intrathoracic pressure, leading to an increase in LV transmural pressure and enhanced ventricular afterload without an increase in systemic arterial pressure.44 All of the aforementioned effects of enhanced negative intrathoracic pressure have been demonstrated to affect LV filling.44,45 Abnormalities in diastolic function, substantially related to repetitive OSA events during sleep, are very common in patients with OSA. These alterations could be reversed, at least in part, with continuous positive airway pressure therapy.46
Patients with a variety of diseases and DHF have different pressure-volume mechanisms involved in their pathology. At one end of the spectrum are patients who have heart failure on the basis of diastolic dysfunction, and at the other end are patients with arterial hypertension. In the latter group, hearts appear to be very mildly dilated, with little or no detectable abnormality of systolic or diastolic pressure-volume relationships, and subtle changes in total body volume may induce DHF.47 Another scenario involves ischemic heart disease with or without minor myocardial infarction where mild systolic dysfunction is not evident by measurement of ejection fraction but is sufficient to induce a neurohormonal response that can lead to salt and water retention.22,47
| Diagnosis |
|---|
|
|
|---|
In 1998, the European Society of Cardiology proposed the presence of all of the following criteria48 to make the diagnosis of DHF:
45%) Vasan and Levy49 modified these criteria by categorizing patients in three diagnostic groups: definite, probable, and possible.49 Patients with definite DHF have the signs and symptoms of CHF and documented abnormal LV relaxation during catheterization. In patients without documented abnormal LV relaxation during catheterization with the signs and symptoms of CHF, DHF was considered probable.23 Patients without documented abnormal LV relaxation during cardiac catheterization were classified as possible DHF. The study23 further suggested that the diagnosis of possible CHF might be upgraded to probable if there is evidence of severe hypertension during the acute event. Although an LVEF greater than 50% within 72 hours of the heart failure event was required to meet any of these grouping criteria, this measurement has been challenged as an indicator of DHF. In some studies,15,50 echocardiographic findings in this timeframe are unchanged when compared with posttreatment findings in patients who present with severe hypertension and acute pulmonary edema.
Echocardiography continues to be used as an important tool for the diagnosis of LV diastolic dysfunction.51 With the onset of LV filling, the early atrioventricular pressure gradient causes the blood to flow across the mitral valve, resulting in an early filling wave (E wave). As the blood enters the left ventricle, the LV pressure increases and the left atrial (LA) pressure decreases until the pressure gradient across the mitral valve disappears, causing a deceleration of the early doppler filling wave. After a period of diastatic left atrium contractions, the flow across the mitral valve (A wave) accelerates. In healthy young adults, the E/A wave ratio of the mitral inflow pattern is usually greater than 1. As patients age, this ratio reverses and the relaxation time increases. If the LV end diastolic pressure continues to rise, the LA to LV pressures equalize, therefore shortening the deceleration time. Further progression of diastolic dysfunction results in a restrictive filling pattern with a very short deceleration time. In addition, shorter deceleration of the E wave is associated with increased LV stiffness.52
While standard pulsed-wave Doppler echocardiography provides the temporal distribution of blood flow velocities in a specific location, color M-mode Doppler echocardiography reveals the spatiotemporal distribution of these velocities across a vertical line. Thus, the information displayed in a color M-mode recording of the LV inflow is comparable with multiple simultaneous pulse Doppler tracings obtained at different levels from the mitral orifice to the LV apex. A first wave propagates from the LA to the LV apex, corresponding to early filling, and a second wave follows atrial contraction. The magnitude of these velocities is highest above the mitral leaflet tips and decreases as flow approaches the apex. In health ventricles, the spatial position of the maximal velocity is closer to the ventricular apex for the E wave than it is for the A wave, suggesting that intraventricular pressure gradients during early filling produce a suction force that accelerates flow beyond the mitral orifice. The velocity at which flow propagates within the ventricle is given by the slope of the wavefront, which is used to assess LV diastolic function.
Tissue Doppler echocardiography provides additional information that helps to accurately quantify LV diastolic function. Tissue Doppler echocardiography may be used to quantify myocardial velocities in multiple segments of the myocardium from different echocardiographic acoustic windows. If we examine a typical spectral display, we can observe a velocity signal directed toward the LV centroid during systole and two distinct signals directed away from the centroid during early and late diastole. Both of these parameters are important in establishing the diagnosis of LV dysfunction.
The general clinical and echocardiographic evaluation of diastolic function recognizes four distinct stages from normal to advanced disease, incorporating color M-mode and tissue Doppler parameters to the criteria accepted by the Canadian Consensus on Diastolic Dysfunction (Figure 1).53 These patterns are not unique to a specific disease but represent a spectrum, which may be influenced by aging and changing hemodynamic variables.54
|
The psuedonormal pattern, stage II of diastolic dysfunction, is often the most difficult to identify. In affected patients, filling indices resemble those found in healthy subjects. Left ventricular relaxation rate and compliance are reduced, but filling pressure increases as a compensatory mechanism to maintain cardiac output. Stage III of diastolic dysfunction is the restrictive filling pattern. This stage is seen in the presence of profound abnormalities of LV compliance and a markedly increased filling pressure. Left ventricular relaxation is reduced, perhaps with the only exception being in patients with isolated constrictive pericarditis. Echocardiographic features of advanced structural heart disease are typically evident.
| Treatment |
|---|
|
|
|---|
Calcium channel blockers are believed to help control heart rate, lower blood pressure, and treat ischemia.57,58 By causing regression of LV hypertrophy, calcium channel blockers may also improve the diastolic properties of the left ventricle.57,58 In patients with DHF, verapamil improved clinical status, exercise tolerance, and diastolic filling.55 In a small prospective study,57 an improvement was evident after 2 weeks of verapamil treatment (mean, 256 mg/d) in patients with CHF and an ejection fraction greater than 45%. In a hypertensive rat model,59 amlodipine besylate prevented an elevation of LV end-diastolic pressure and transition to overt DHF by controlling blood pressure and reducing myocardial stiffness. However, as a result of the small number of patients studied in these trials, the usefulness of calcium channel blockers in diastolic dysfunction and DHF remains debatable.
The Candesartan in Heart Failure: Assessment of Reduction in Mortality and Morbidity (CHARM-Preserved) study56 is perhaps the only completed large-scale prospective randomized trial to specifically address the impact of pharmacotherapy on outcomes in a subgroup of patients with CHF and a preserved ejection fraction. In this study, 3023 patients who had DHF were randomized to 32 mg of candesartan daily or to placebo. At 37-month median follow-up, candesartan reduced hospitalization for CHF by 11%. The annual event rates (ie, hospital admission for heart failure) were 8% in the candesartan group and 9% in the placebo group.56
The effects of aldosterone antagonism on myocardial function in hypertensive patients with suspected diastolic heart failure has been studied in randomized, double-blinded, placebo-controlled trials by using sensitive quantitative echocardiographic techniques.60-62 One study60 demonstrated that in an ambulatory hypertensive population with isolated LV diastolic dysfunction and reduced functional capacity because of exertional dyspnea, myocardial function improved after 6 months with aldosterone antagonism by using a hemodynamically insignificant dose of spironolactone.
Digoxin, an antiarrhythmic drug, is not specifically indicated for the treatment of patients with DHF. However, it has been reported to reduce the hospitalization rate in patients who had CHF and an LVEF greater than 45%.63 Any benefits of digoxin in treating patients with DHF may be related to controlling heart rate, especially in the presence of atrial arrhythmia.63
In the absence of large controlled clinical trials, DHF is determined by a set of logical principles.64 For example, physicians' and patients' goals should be to control systemic arterial blood pressure and tachycardia, reduce central venous blood volume, and alleviate myocardial ischemia.64 The American College of Cardiology and American Heart Association Task Force guidelines for the management of heart failure and the preservation of left ventricular systolic function are provided in Figure 2.64 Improving alveolar hypoxemia and pulmonary arterial hypertension, when present, are also important treatment goals.65 Together, these interventions minimize right ventricular overload influences on the left ventricle.
|
| Prognosis |
|---|
|
|
|---|
| Conclusion |
|---|
|
|
|---|
Received for publication January 8, 2007. Revision received June 25, 2007. Accepted for publication August 14, 2007.
| References |
|---|
|
|
|---|
2. Bursi F, Weston SA, Redfield MM, Jacobsen SJ, Pakhomov S, Nkomo VT,
et al. Systolic and diastolic heart failure in the community.
JAMA. 2006;296:2209
-2216.
3. Liao L, Jollis JG, Anstrom KJ, Whellan DJ, Kitzman DW, Aurigemma GP, et al. Costs for heart failure with normal vs reduced ejection fraction. Arch Intern Med. 2006;166:112-118. Available at: http://archinte.amaassn.org/cgi/content/full/166/1/112. Accessed April 2, 2008.
4. Yancy CW, Lopatin M, Stevenson LW, De Marco T, Fonarow GC. Clinical
presentation, management, and in-hospital outcomes of patients admitted with
acute decompensated heart failure with preserved systolic function: a report
from the Acute Decompensated Heart Failure National Registry (ADHERE) Database
[published correction appears in J Am Coll Cardiol. 2006;47:1502].
J Am Coll Cardiol.2006; 47:76
-84.
5. Tsutsui H, Tsuchihashi M, Takeshita A. Mortality and readmission of hospitalized patients with congestive heart failure and preserved versus depressed systolic function. Am J Cardiol.2001; 88:530 -533.[Medline]
6. Senni M, Tribouilloy CM, Rodeheffer RJ, Jacobsen SJ, Evans JM, Bailey KR, et al. Congestive heart failure in the community: a study of all incident cases in Olmsted County, Minnesota, in 1991. Circulation. 1998;98:2282-2289. Available at: http://circ.ahajournals.org/cgi/content/full/98/21/2282. Accessed April 2, 2008.
7. Kitzman DW, Gardin JM, Gottdiener JS, Arnold A, Boineau R, Aurigemma G, et al. Importance of heart failure with preserved systolic function in patients > or = 65 years of age. CHS Research Group. Cardiovascular Health Study. Am J Cardiol.2001; 87:413 -419.[Medline]
8. MacCarthy PA, Kearney MT, Nolan J, Lee AJ, Prescott RJ, Shah AM, et al. Prognosis in heart failure with preserved left ventricular systolic function: prospective cohort study. BMJ. 2003;327:78-79. Available at: http://www.bmj.com/cgi/content/full/327/7406/78. Accessed April 2, 2008.
9. Vasan RS, Larson MG, Benjamin EJ, Evans JC, Reiss CK, Levy D.
Congestive heart failure in subjects with normal versus reduced left
ventricular ejection fraction: prevalence and mortality in a population-based
cohort. J Am Coll Cardiol.1999; 33:1948
-1955.
10. Aurigemma GP, Gottdiener JS, Shemanski L, Gardin J, Kitzman D.
Predictive value of systolic and diastolic function for incident congestive
heart failure in the elderly: the cardiovascular health study. J Am
Coll Cardiol. 2001;37:1042
-1048.
11. Kitzman DW, Little WC, Brubaker PH, Anderson RT, Hundley WG, Marburger CT, et al. Pathophysiological characterization of isolated diastolic heart failure in comparison to systolic heart failure. JAMA. 2002;288:2144-2150. Available at: http://jama.ama-assn.org/cgi/content/full/288/17/2144. Accessed April 2, 2008.
12. Tardif JC, Rouleau JL. Diastolic dysfunction. Can J Cardiol. 1996;12:389 -398.[Medline]
13. Zile MR, Baicu CF, Gaasch WH. Diastolic heart failure—abnormalities in active relaxation and passive stiffness of the left ventricle. N Engl J Med. 2004;350:1953-1959. Available at: http://content.nejm.org/cgi/content/abstract/350/19/1953. Accessed April 2, 2008.
14. Zile MR, Brutsaert DL. New concepts in diastolic dysfunction and diastolic heart failure: part II. Causal mechanisms and treatment. Circulation. 2002;105:1503-1508. Available at: http://circ.ahajournals.org/cgi/content/full/105/12/1503. Accessed April 2, 2008.
15. Gandhi SK, Powers JC, Nomeir AM, Fowle K, Kitzman DW, Rankin KM, et al. The pathogenesis of acute pulmonary edema associated with hypertension. N Engl J Med. 2001;344:17-22. Available at: http://content.nejm.org/cgi/content/abstract/344/1/17. Accessed April 2, 2008.
16. Kitzman DW, Higginbotham MB, Cobb FR, Sheikh KH, Sullivan MJ. Exercise intolerance in patients with heart failure and preserved left ventricular systolic function: failure of the Frank-Starling mechanism. J Am Coll Cardiol.1991; 17:1065 -1072.[Abstract]
17. Litwin SE, Grossman W. Diastolic dysfunction as a cause of heart failure. J Am Coll Cardiol.1993; 22(4 suppl A):49A -55A.[Medline]
18. Apstein CS, Morgan JP. Cellular mechanism underlying left ventricular diastolic failure. In: Gaasch WH, Lewinter MM, eds. Left Ventricular Diastolic Dysfunction and Heart Failure. Philadelphia, Pa: Lea & Febiger; 1994:3 -24.
19. Angeja BG, Grossman W. Evaluation and management of diastolic heart failure. Circulation. 2003;107:659-663. Available at: http://circ.ahajournals.org/cgi/reprint/107/5/659. Accessed April 3, 2008.
20. Froehlich JP, Lakatta EG, Beard E, Spurgeon HA, Weisfeldt ML, Gerstenblith G. Studies of sarcoplasmic reticulum function and contraction duration in young adult and aged rat myocardium. J Mol Cell Cardiol. 1978;10:427 -438.[Medline]
21. Tokushima T, Reid CL, Gardin JM. Left ventricular diastolic function in the elderly. Am J Geriatr Cardiol.2001; 10:20 -29.[Medline]
22. Maurer MS, Kronzon I, Burkhoff D. Ventricular pump function in heart failure with normal ejection fraction: insights from pressure-volume measurements. Prog Cardiovasc Dis.2006; 49:182 -195.[Medline]
23. Eberli FR, Strömer H, Ferrell MA, Varma N, Morgan JP, Neubauer S, et al. Lack of direct role for calcium in ischemic diastolic dysfunction in isolated hearts. Circulation. 2000;102:2643-2649. Available at: http://circ.ahajournals.org/cgi/content/full/102/21/2643. Accessed April 3, 2008.
24. Apstein CS, Grossman W. Opposite initial effects of supply and demand ischemia on left ventricular diastolic compliance: the ischemia-diastolic paradox. J Mol Cell Cardiol.1987; 19:119 -128.[Medline]
25. Varma N, Eberli FR, Apstein CS. Increased diastolic chamber stiffness during demand ischemia: response to quick length change differentiates rigor-activated from calcium-activated tension. Circulation. 2000;101:2185-2192. Available at: http://circ.ahajournals.org/cgi/content/full/101/18/2185. Accessed April 3, 2008.
26. Varma N, Eberli FR, Apstein CS. Left ventricular diastolic
dysfunction during demand ischemia: rigor underlies increased stiffness
without calcium-mediated tension. Amelioration by glycolytic substrate.
J Am Coll Cardiol.2001; 37:2144
-2153.
27. Zannad F, Dousset B, Alla F. Treatment of congestive heart failure: interfering the aldosterone-cardiac extracellular matrix relationship. Hypertension. 2001;38:1227-1232. Available at: http://hyper.ahajournals.org/cgi/content/full/38/5/1227. Accessed April 3, 2008.
28. Zhou G, Kandala JC, Tyagi SC, Katwa LC, Weber KT. Effects of angiotensin II and aldosterone on collagen gene expression and protein turnover in cardiac fibroblasts. Mol Cell Biochem.1996; 154:171 -178.[Medline]
29. Funck RC, Wilke A, Rupp H, Brilla CG. Regulation and role of myocardial collagen matrix remodeling in hypertensive heart disease. Adv Exp Med Biol.1997; 432:35 -44.[Medline]
30. Chua CC, Hamdy RC, Chua BH. Angiotensin II induces TIMP-1 production in rat heart endothelial cells. Biochim Biophys Acta. 1996;1311:175 -180.[Medline]
31. Pauschinger M, Knopf D, Petschauer S, Doerner A, Poller W, Schwimmbeck PL, et al. Dilated cardiomyopathy is associated with significant changes in collagen type I/III ratio. Circulation. 1999;99:2750-2756. Available at: http://circ.ahajournals.org/cgi/content/full/99/21/2750. Accessed April 3, 2008.
32. Brilla CG, Zhou G, Matsubara L, Weber KT. Collagen metabolism in cultured adult rat cardiac fibroblasts: response to angiotensin II and aldosterone. J Mol Cell Cardiol.1994; 26:809 -820.[Medline]
33. Guarda E, Katwa LC, Myers PR, Tyagi SC, Weber KT. Effects of
endothelins on collagen turnover in cardiac fibroblasts. Cardiovasc
Res. 1993;27:2130
-2134.
34. Barberá JA, Peinado VI, Santos S. Pulmonary hypertension in chronic obstructive pulmonary disease. Eur Respir J. 2003;21:892-905. Available at: http://erj.ersjournals.com/cgi/content/full/21/5/892. Accessed April 3, 2008.
35. Baum GL, Schwartz A, Llamas R, Castillo C. Left ventricular function in chronic obstructive lung disease. N Engl J Med. 1971;285:361 -365.[Medline]
36. Braunwald E, Zipes DP, Libby P. Heart Disease: A Textbook of Cardiovascular Medicine. 6th ed. Philadelphia, Pa: W.B. Saunders; 2001.
37. Schena M, Clini E, Errera D, Quadri A. Echo-Doppler evaluation of left ventricular impairment in chronic cor pulmonale. Chest. 1996;109:1446-1451. Available at: http://www.chestjournal.org/cgi/reprint/109/6/1446. Accessed April 3, 2008.
38. Gomez A, Mink S. Increased left ventricular stiffness impairs filling in dogs with pulmonary emphysema in respiratory failure. J Clin Invest. 1986;78:228-240. Available at: http://www.jci.org/articles/view/112556/pdf. Accessed April 3, 2008.
39. Somers VK, Dyken ME, Clary MP, Abboud FM. Sympathetic neural mechanisms in obstructive sleep apnea. J Clin Invest. 1995;96:1897-1904. Available at: http://www.jci.org/articles/view/118235/pdf. Accessed April 3, 2008.
40. Bradley TD, Hall MJ, Ando S, Floras JS. Hemodynamic effects of simulated obstructive apneas in humans with and without heart failure. Chest. 2001;119:1827-1835. Available at: http://www.chestjournal.org/cgi/content/full/119/6/1827. Accessed April 3, 2008.
41. Arai M, Alpert NR, MacLennan DH, Barton P, Periasamy M. Alterations in sarcoplasmic reticulum gene expression in human heart failure. A possible mechanism for alterations in systolic and diastolic properties of the failing myocardium. Circ Res.1993; 72:463 -469.[Abstract]
42. Gaasch WH, Blaustein AS, Andrias CW, Donahue RP, Avitall B. Myocardial relaxation. II. Hemodynamic determinants of rate of left ventricular isovolumic pressure decline. Am J Physiol.1980; 239:H1 -H6.[Medline]
43. Lorell BH, Carabello BA. Left ventricular hypertrophy: pathogenesis, detection, and prognosis. Circulation. 2000;102:470-479. Available at: http://circ.ahajournals.org/cgi/content/full/102/4/470. Accessed April 3, 2008.
44. Virolainen J, Ventilä M, Turto H, Kupari M. Effect of negative
intrathoracic pressure on left ventricular pressure dynamics and relaxation.
J Appl Physiol.1995; 79:455
-460.
45. Brinker JA, Weiss JL, Lappé DL, Rabson JL, Summer WR, Permutt S, et al. Leftward septal displacement during right ventricular loading in man. Circulation.1980; 61:626 -633.[Medline]
46. Arias MA, García-Río F, Alonso-Fernández A, Mediano O, Martínez I, Villamor J. Obstructive sleep apnea syndrome affects left ventricular diastolic function: effects of nasal continuous positive airway pressure in men. Circulation. 2005;112:375-383. Available at: http://circ.ahajournals.org/cgi/content/full/112/3/375. Accessed April 3, 2008.
47. Maurer MS, King DL, El-Khoury Rumbarger L, Packer M, Burkhoff D. Left heart failure with a normal ejection fraction: identification of different pathophysiologic mechanisms. J Card Fail.2005; 11:177 -187.[Medline]
48. How to diagnose diastolic heart failure. European Study Group on Diastolic Heart Failure. Eur Heart J. 1998;19:990-1003. Available at: http://eurheartj.oxfordjournals.org/cgi/reprint/19/7/990. Accessed April 3, 2008.
49. Vasan RS, Levy D. Defining diastolic heart failure: a call for standardized diagnostic criteria. Circulation. 2000;101:2118-2121. Available at: http://circ.ahajournals.org/cgi/content/full/101/17/2118. Accessed April 3, 2008.
50. Smith GL, Masoudi FA, Vaccarino V, Radford MJ, Krumholz HM.
Outcomes in heart failure patients with preserved ejection fraction:
mortality, readmission, and functional decline. J Am Coll
Cardiol. 2003;41:1510
-1518.
51. Cohen GI, Pietrolungo JF, Thomas JD, Klein AL. A practical guide to assessment of ventricular diastolic function using Doppler echocardiography. JAm Coll Cardiol.1996; 27:1753 -1760.[Abstract]
52. Garcia M, Smedira N, Greenberg NL, Wong J, Zhou J, Rodriguez L, et al. Transmitral early deceleration time predicts LV pressure changes: implications for the non-invasive estimation of LV stiffness [abstract]. J Am Coll Cardiol.1998; 31:163A .
53. Garcia MJ, Thomas JD, Klein AL. New Doppler echocardiographic
applications for the study of diastolic function. J Am Coll
Cardiol. 1998;32:865
-875.
54. Rakowski H, Appleton C, Chan KL, Dumesnil JG, Honos G, Jue J, et al. Canadian consensus recommendations for the measurement and reporting of diastolic dysfunction by echocardiography: from the Investigators of Consensus on Diastolic Dysfunction by Echocardiography. J Am Soc Echocardiogr. 1996;9:736 -760.[Medline]
55. Setaro JF, Zaret BL, Schulman DS, Black HR, Soufer R. Usefulness of verapamil for congestive heart failure associated with abnormal left ventricular diastolic filling and normal left ventricular systolic performance. Am J Cardiol.1990; 66:981 -986.[Medline]
56. Yusuf S, Pfeffer MA, Swedberg K, Granger CB, Held P, McMurray JJ, et al; CHARM Investigators and Committees. Effects of candesartan in patients with chronic heart failure and preserved left-ventricular ejection fraction: the CHARM-Preserved Trial. Lancet.2003; 362:777 -781.[Medline]
57. Schnieder RE, Messerli FH, Garavaglia GE, Nunez BD. Cardiovascular effects of verapamil in patients with essential hypertension. Circulation.1987; 75:1030 -1036.[Medline]
58. Amodeo C, Kobrin I, Ventura HO, Messerli FH, Frohlich ED. Immediate and short-term hemodynamic effects of diltiazem in patients with hypertension. Circulation.1986; 73:108 -113.[Medline]
59. Nishikawa N, Masuyama T, Yamamoto K, Sakata Y, Mano T, Miwa T, et
al. Long-term administration of amlodipine prevents decompensation to
diastolic heart failure in hypertensive rats. J Am Coll
Cardiol. 2001;38:1539
-1545.
60. Mottram PM, Haluska B, Leano R, Cowley D, Stowasser M, Marwick TH. Effect of aldosterone antagonism on myocardial dysfunction in hypertensive patients with diastolic heart failure. Circulation. 2004;110:558-565. Available at: http://circ.ahajournals.org/cgi/content/full/110/5/558. Accessed April 3, 2008.
61. Thohan V, Torre-Amione G, Koerner MM. Aldosterone antagonism and congestive heart failure: a new look at an old therapy. Curr Opin Cardiol. 2004;19:301 -308.[Medline]
62. Buss SJ, Backs J, Kreusser MM, Hardt SE, Maser-Gluth C, Katus HA, et al. Spironolactone preserves cardiac norepinephrine reuptake in salt-sensitive Dahl rats. Endocrinology. 2006;147:2526-2534. Available at: http://endo.endojournals.org/cgi/content/full/147/5/2526. Accessed April 16, 2008.
63. The effect of digoxin on mortality and morbidity in patients with
heart failure. The Digitalis Investigation Group. N Engl J
Med. 1997;336:525
-533.
64. Hunt SA, Abraham WT, Chin MH, Feldman AM, Francis GS, Ganiats TG, et al. ACC/AHA 2005 Guideline Update for the Diagnosis and Management of Chronic Heart Failure in the Adult: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Update the 2001 Guidelines for the Evaluation and Management of Heart Failure): developed in collaboration with the American College of Chest Physicians and the International Society for Heart and Lung Transplantation: endorsed by the Heart Rhythm Society. Circulation. 2005;112:e154-e235. Available at: http://circ.ahajournals.org/cgi/content/full/112/12/e154. Accessed April 3, 2008.
65. Larsen KO, Sjaastad I, Svindland A, Krobert KA, Skjønsberg OH, Christensen G. Alveolar hypoxia induces left ventricular diastolic dysfunction and reduces phosphorylation of phospholamban in mice. Am J Physiol Heart Circ Physiol. 2006;291:H507-H516. Available at: http://ajpheart.physiology.org/cgi/content/full/291/2/H507. Accessed April 16, 2008.
66. Little WC, Zile MR, Kitzman DW, Hundley WG, O'Brien TX, Degroof RC. The effect of alagebrium chloride (ALT-711), a novel glucose cross-link breaker, in the treatment of elderly patients with diastolic heart failure. J Card Fail.2005; 11:191 -195.[Medline]
67. Cohn JN, Johnson G. Heart failure with normal ejection fraction. The V-HeFT Study. Veterans Administration Cooperative Study Group. Circulation.1990; 81(suppl 2):III48 -III53.[Medline]
68. Mathew ST, Gottdiener JS, Kitzman D, Aurigemma G. Congestive heart failure in the elderly: the Cardiovascular Health Study. Am J Geriatr Cardiol. 2004;13:61 -68.[Medline]
69. Rich MW, McSherry F, Williford WO, Yusuf S; Digitalis Investigation
Group. Effect of age on mortality, hospitalizations and response to digoxin in
patients with heart failure: the DIG study. J Am Coll
Cardiol. 2001;38:806
-813.
70. Owan TE, Redfield MM. Epidemiology of diastolic heart failure. Prog Cardiovasc Dis.2005; 47:320 -332.[Medline]
| ||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |