Applied Evidence

The less familiar side of heart failure: Symptomatic diastolic dysfunction

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Diastolic heart failure is not as well studied as systolic, but its prevalence has probably been underestimated


 

References

Practice recommendations
  • Arrange for echocardiography or radionuclide angiography within 72 hours of a heart failure exacerbation. An ejection fraction >50% in the presence of signs and symptoms of heart failure makes the diagnosis of diastolic heart failure probable (B).
  • To treat associated hypertension, use angiotensin receptor blockers (ARBs), angiotensin-converting enzyme (ACE) inhibitors, beta-blockers, calcium channel blockers, or diuretics to achieve a blood pressure goal of <130/80 mm Hg (C).
  • When using beta-blockers to control heart rate, titrate doses more aggressively than would be done for systolic failure, to reach a goal of 60 to 70 bpm (B).
  • Use ACE inhibitors/ARBs to decrease hospitalizations, decrease symptoms, and prevent left ventricular remodeling (A).

Heart failure is a growing epidemic in the US, estimated to cause at least 20% of all hospitalizations in persons over 65 years of age. It is also the leading inpatient diagnosis among Medicare recipients with this age group.1,2,3 More than 5 million people in the US have heart failure, with approximately 550,000 new cases diagnosed annually.

Growing epidemiologic evidence suggests that studies of heart failure have underrepresented a large patient population with a natural history different from that of left ventricular (LV) systolic dysfunction.4-8One third to one half of patients with signs and symptoms of heart failure have preserved left ventricular function (LVF). They are said to have diastolic heart failure (DHF).

Identifying persons with this less-understood form of heart failure can be challenging. Skillful discernment is needed to avoid mistakenly attributing symptoms to other causes. DHF is particularly common among elderly women with hypertension; every patient with signs and symptoms of heart failure should undergo echocardiography to determine LV function.

Though the evidence base for DHF treatment is less well established than it is for systolic heart failure (SHF), data from recent trials have offered a promising direction.

New categorization of heart failure

The relative scopes of DHF and SHF will be better appreciated by understanding how recently developed guidelines have restructured the historical classification of heart failure.

Heart failure is defined by the American College of Cardiology (ACC) and the American Heart Association (AHA) as a complex syndrome resulting from any structural or functional cardiac disorder that impairs the ability of the ventricles to fill with or eject blood.9 The older terms, low-vs high-output failure, are now regarded as obsolete and have been abandoned in favor of distinguishing between abnormalities of systolic and diastolic function.10-12

ACC/AHA heart failure staging system

Severity of heart failure symptoms has traditionally been gauged by the New York Heart Association (NYHA) classification system. A criticism of the NYHA scale, however, is that patients may fluctuate in and out of the varying functional classes. To correct this shortcoming of the NYHA scale, the ACC and the AHA devised a new staging system to describe the progression of heart failure.9 The premise of this new system is to provide permanence to each sequential progression through the stages of heart failure while complementing the existing NYHA scale.9,13

New model. Patients with Stage A heart failure are at high risk of developing heart failure based on comorbidities and medical history.

Patients with Stage B heart failure have some component of structural heart disease but are asymptomatic.

Patients with Stage C heart failure have underlying structural abnormalities and have symptoms, or have had symptoms of heart failure in the past.

Patients with Stage D heart failure are refractory to conventional medical therapy and have end-stage symptoms.

TABLE 1 shows how the ACC/AHA Heart Failure Staging System correlates with the NYHA Classification scheme. Family practitioners can use the new heart failure staging system to identify and recognize risk factors for the development of heart failure and then seek to aggressively prevent or reverse them.

TABLE 1
Relationship of the ACC/AHA Heart Failure

ACC/AHA STAGES OF HEART FAILURENYHA FUNCTIONAL CLASSIFICATION
A- high risk for development of HF; no underlying structural cardiac disease (ie, hypertension, diabetes, hyperlipidemia, etc)No correlation
B- Structural heart disease but asymptomatic (ie, LVH)I- patients with no limitation of activities; they suffer no symptoms from ordinary physical activity
C- Structural heart disease with past or current symptoms of heart failureII- patients with slight, mild limitation of activity; they are comfortable with rest or with mild exertion
III- patients with marked limitation of activity; they are comfortable only at rest
D- Refractory heart failureIV- patients who should be at complete rest, confined to bed or chair; any physical activity brings on discomfort and symptoms occur at rest
Patients with Stage A heart failure are at high risk of developing clinical HF and are not representative of any patients categorized under the NHYA functional classification system, as they are not yet symptomatic. Patients with Stage B heart failure have some form of structural heart disease without associated symptoms and correlate best with NYHA Class I patients. Patients with Stage C heart failure have the same underlying structural cardiac disorders associated with Stage B, but they have past or current symptoms of HF. Depending on the severity of their condition, patients with Stage C heart failure may fall within any of the NYHA functional classes. Patients with Stage D heart failure have symptoms refractory to optimized medical and interventional therapies and are representative of NYHA Class IV patients.

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