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Diastolic Heart Failure

When a normal ejection fraction can be misleading

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For years, scientists and clinicians believed that systole was the cornerstone mechanism of heart functioning. As a result, all treatments for heart failure (HF) were directed at treating systolic dysfunction.1 But the heart is actually in diastole two-thirds of the time.1 In the 1980s, the medical community began to recognize that some patients with a normal ejection fraction were experiencing signs and symptoms of heart failure.1 Scientists evaluated these patients and found that even though systolic function was adequate, diastolic function was suboptimal.1 At this time, diastolic dysfunction was deemed to be clinically significant.1

Today, patients with signs and symptoms of HF and diastolic dysfunction now are diagnosed with heart failure with a normal ejection fraction (HFNEF), or diastolic HF.1 Perhaps as much as 50% of patients with heart failure have diastolic dysfunction and a normal ejection fraction.1 Research has demonstrated a higher incidence of HFNEF in older women with the risk factors of hypertension, obesity, left ventricular hypertrophy, anemia, renal failure, atrial fibrillation or diabetes are at risk.1,2

What is HFNEF?

Heart failure occurs when the heart is unable to pump an adequate amount of blood to the tissues for perfusion and oxygenation.3 The heart has two mechanisms of action for maintaining adequate blood flow: systole (contraction phase) and diastole (resting phase).2,3 Systolic dysfunction occurs when the heart is unable to fulfill the metabolic requirements of the tissues.4 The left ventricular ejection fraction (LVEF) is a measurement of the systolic function.4 Diastolic dysfunction occurs when the ventricle is unable to relax and/or fill with the appropriate amount of blood needed to perfuse the tissues.2,4 A patient with signs and symptoms of HF in the presence of diastolic dysfunction is diagnosed with HFNEF.2

The major causes of HFNEF are related to structural remodeling and functional abnormalities of the heart.2,4 These abnormalities are commonly caused by chronic hypertension with left ventricular hypertrophy, diastolic dysfunction, cardiomyopathy, heart valve disorders, atrial fibrillation, excessive alcohol use, end-stage COPD, diabetes and CAD.2,4 Patients with diastolic dysfunction may be asymptomatic for many years prior to the onset of HF.5 This is a barrier to conducting research in this patient population.5

Clinical Presentation

Typically, patients with diastolic HF present with the same symptoms as patients with systolic heart failure.6 All of the symptoms are related to fluid volume overload resulting in pulmonary congestion and peripheral edema.6 Symptoms vary depending on the level of HF the patient is experiencing.6 During the interview, the patient may report nocturnal dyspnea, sleeping with extra pillows or in a recliner at night, weight gain, and shortness of breath with exercise or at rest.6 The heart failure patient may also complain of chest pain, palpitations, weakness, fatigue and decreased endurance related to increased demand on the myocardium and decreased cardiac output.6,7

The pulmonary congestion may cause the patient to complain of a cough.However, the provider must also be aware that the cough could be a potential side effect of an angiotensin-converting enzyme (ACE) inhibitor.3 Abnormal findings on the physical exam may Archive ImageAinclude jugular venous pressure greater than 6 cm at a 45-degree angle; a positive hepatojugular reflex; an S3 gallop; lower extremity edema; ascites; increased abdominal girth; displaced point of maximum impulse; and rales/crackles in the lungs.3 All of these findings are generalized for heart failure and not specific to systolic or diastolic HF.

Diagnosis of HFNEF

According to the American College of Cardiology (ACC), a diagnosis of HFNEF is made when diastolic dysfunction occurs in the presence of signs and symptoms of heart failure.8 A transthoracic echocardiogram is the gold standard for differentiating systolic dysfunction from diastolic dysfunction.8,9 In patients with HFNEF, the LVEF is normal (greater than 50%), the left ventricular end diastolic pressure is elevated (greater than 97 mL/m2), and valve structure and function are normal.6,10 Tissue Doppler and pulse wave Doppler are performed during an echocardiogram to evaluate intracardiac velocities, which also help diagnose and grade the degree of diastolic dysfunction (I-IV).11

Several other diagnostic tests can be performed to confirm a diagnosis of HF. However, these tests do not distinguish systolic from diastolic HF.8 Brain natriuretic peptide (BNP) is a hormone released into the bloodstream when myocardial stretch and increased filling pressures are present.3 BNP levels greater than 400 pg/mL in the presence of dyspnea should prompt consideration of HF.3 Electrocardiography and chest x-ray can evaluate for underlying causes including myocardial ischemia, left ventricular hypertrophy, cardiomegaly, pulmonary edema and atrial fibrillation.8 All of these components are helpful in diagnosing HFNEF.

Management and Treatment

Evidence-based treatments for HFNEF are lacking.8 Most of the available evidence-based research supports treatment of HF with a reduced ejection fraction or systolic heart failure.8 In 2005, The ACC and the American Heart Association (AHA) developed general guidelines for treating HFNEF.10 These recommend treating hypertension, controlling the ventricular rate in patients with sinus tachycardia or atrial fibrillation, preventing pulmonary and peripheral edema, and managing myocardial ischemia.10 The management of underlying conditions helps reduce HF exacerbations.6

Nonpharmacologic Management

Education. Providers must educate the patient and family to recognize the signs and symptoms of fluid volume overload to This recognition can decrease the risk of decompensated HF with hospital admission.7 The patient and family should also be informed that diet, exercise and medication adherence are key components to successful heart failure management.

Weight Measurement. Patients should report a sudden weight gain of greater than 3 to 5 pounds over 3 days because it could indicate worsening HF.7 Providers can increase diuretic dosage to help the patient avoid complications of pulmonary edema and an increased demand for oxygen, both of which an result in hospitalization.7

Diet. Dietary education for patients with HFNEF should include a salt restriction of less than 2,000 mg per day and a fluid restriction of 2,000 mL or less to prevent fluid volume overload.3,7 Alcohol should be limited to one or two glasses of wine or one can of beer daily.7

Exercise. Patients should participate in aerobic exercise under the direction of a provider to improve the body's utilization of oxygen and increase activity tolerance.7,9 Many studies have demonstrated that aerobic exercise improves blood pressure, reduces cholesterol, decreases weight and improves mental well-being.12

Tobacco Cessation. Nicotine increases heart rate and blood pressure.12 It also causes structural damage to the intimal lining of the blood vessels.12 Therefore, smoking cessation in a patient with HFNEF is beneficial.12 Evaluate readiness to quit and offer assistance with cessation programs or medication.12

Sleep Apnea. Obstructive sleep apnea (OSA) may worsen HF outcomes, so all patients with this condition should be evaluated for OSA.9 The periods of hypoxia in OSA worsen hypertension, which can contribute to systolic and diastolic dysfunction.9 Patients who are at risk for sleep apnea should undergo an overnight sleep study (polysomnography).9

Pharmacologic Management

Few clinical trials have examined the pharmacologic treatment of HFNEF.10 Recommendations for the pharmacologic management of patients with HFNEF are therefore based on the guidelines established by the ACC and AHA, as well as as each patient's underlying conditions.10

Initially, treatment should be directed at reducing the congested state. Loop diuretics (i.e., hydrochlorothiazide) should be initiated to decrease circulating volume, pulmonary congestion and blood pressure in the hypertensive patient. The use of an angiotensin-converting enzyme inhibitor (ACE inhibitor; i.e., lisinopril) can decrease left ventricular hypertrophy and promote left ventricular relaxation.14 Therefore, patients with HFNEF should be started on an ACE inhibitor.14 Angiotensin receptor blockers (ARBs) can be used if an ACE inhibitor is not tolerated.14 Studies have demonstrated that ARBs decrease left ventricular mass and increase diastolic filling times.14 However, it is not necessary to use both an ACE inhibitor and an ARB.14

Lastly, the patient with HFNEF should be started on a beta-adrenergic receptor blocker (i.e., carvedilol, metoprolol) to slow the heart rate, improve diastolic filling time and improve hypertension.14

Patients experiencing atrial fibrillation with a rapid ventricular response should undergo cardioversion to restore normal sinus rhythm.8 If this treatment is unsuccessful, calcium channel blockers (CCBs; i.e., verapamil) and anti-arrhythmics (i.e., amiodarone) can be used to achieve rhythm and rate control.8

If a patient experiences myocardial ischemia that contributes to diastolic dysfunction, percutaneous angioplasty may be indicated.8 Nitrates, beta blockers or CCBs may also be used to reduce myocardial oxygen demand.8

It is important to remember that patients with LV diastolic dysfunction and small, stiff LV chambers are susceptible to excessive preload reduction with a possible end result of hypotension.7 Therefore, diuretics and nitrates must be used with caution, especially in older adults.7

The pathophysiology of HFNEF is not fully understood. However, researchers do know that the renin-angiotensin-aldosterone system plays an integral part in regulating blood pressure.8 Aldosterone has been identified as contributing to cardiac hypertrophy and fibrosis.8 Therefore, aldosterone antagonists (i.e., spironolactone) should be considered in the patient with HFNEF to prevent or reverse the effects of the aldosterone on the myocardium and improve ventricular function.

Multiple pharmacologic choices are available for patients with HFNEF. Providers must give careful consideration to comorbid conditions when developing a medication regimen.

Implications for the Provider

The number of patients diagnosed with heart failure every year has progressively increased. The initial treatment for patients with HFNEF should include the administration of diuretics to reduce and maintain a less congested pulmonary state.8 Long-term treatment should include an ACE inhibitor or ARB to manage hypertension, atrial fibrillation and myocardial ischemia.8 All medication regimens must be tailored according to the medical history of each patient. Providers must be vigilant about educating patients about heart failure, lifestyle modifications and the importance of medication adherence.13 It is also important to acknowledge patient-specific barriers to treatment.13 As more research becomes available, providers will need to stay current and be prepared to modify treatment plans as recommended.

References

1. Ferreira-Martins J, Leite-Moreira AF. Physiologic basis and pathophysiologic implications of the diastolic properties of the cardiac muscle. J Biomed Biotechnol. 2010.

2. Maeder MT, Kaye DM. Heart failure with normal left ventricular ejection fraction. J Am Coll Cardiol. 2009;53(11):905-918.

3. Bashore TM, et al. Congestive heart failure. In: McPhee SJ, Papadakis MA, eds. 2011 Current Medical Diagnosis and Treatment. 50th ed. New York: McGraw-Hill; 2010: 385-394.

4. Tzanetos K, et al. Office management of patients with diastolic heart failure. CMAJ. 2009;180(5):520-527.

5. Ramani GV, et al. Chronic heart failure: contemporary diagnosis and management. Mayo Clin Proc. 2010;85(2):180-195.

6. Diastolic heart failure: trouble arises when the heart can't properly relax. Harv Heart Lett. 2010;20(12):5.

7. Swedberg K, et al. Guidelines for the diagnosis and treatment of chronic heart failure: executive summary (update 2005): The Task Force for the Diagnosis and Treatment of Chronic Heart Failure of the European Society of Cardiology. Eur Heart J. 2005;26(11):1115-1140.

8. Aurigemma GP, Gaasch WH. Diastolic heart failure. N Engl J Med. 2004;351(11):1097-1105.

9. Maurer MS. Heart failure with a normal ejection fraction (HFNEF): embracing complexity. J Card Fail. 2009;15(7):561-564.

10. Jessup M, et al. 2009 focused update: ACCF/AHA Guidelines for the Diagnosis and Management of Heart Failure in Adults: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines: developed in collaboration with the International Society for Heart and Lung Transplantation. Circulation. 2009;119(14):1977-2016.

11. Daneshvar D, et al. Diastolic dysfunction: Improved understanding using emerging imaging techniques. Am Heart J. 2010;160(3):394-404.

12. American Heart Association. Smoking and cardiovascular disease (heart disease). http://www.heart.org/HEARTORG/GettingHealthy/QuitSmoking/QuittingResources/Smoking-Cardiovascular-Disease_UCM_305187_Article.jsp#.TziEtfmwUYo

13. van der Wal MH, et al. Unraveling the mechanisms for heart failure patients' beliefs about compliance. Heart Lung. 2007;36(4):253-261.

14. Haney S, et al. Diastolic heart failure: a review and primary care perspective. J Am Board Fam Pract. 2005;18(3):189-198.

Susan M. Jackson is an adult nurse practitioner at the University of Cincinnati in Ohio. She has completed a disclosure statement and reports no relationships related to this article.




     

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