BACKGROUND: In some settings, “diastolic dysfunction” has become a diagnosis of exclusion used to define any patient with symptoms suggestive of CHF but with normal left ventricular (LV) systolic function on echocardiography. This descriptive case series identifies potential diagnoses other than diastolic dysfunction in such patients.
POPULATION STUDIED: The investigators identified 159 consecutive patients with suspected heart failure referred for an outpatient echocardiogram in Scotland. No information was given regarding the previous work-up of these patients or criteria for referral. Fifty (31%) were found to have LV systolic dysfunction, atrial fibrillation, or valvular heart disease and were excluded from further study. Of the remaining 109, most were elderly; 73% were women; and all are presumed to be white. It is likely that the patients are similar to many seen by family physicians in the United States, but clinicians should be cautious about extending the findings to younger persons, men, and people of color.
STUDY DESIGN AND VALIDITY: This study was a case series of patients with preserved LV systolic function but suspected CHF. They obtained a full standardized clinical history for every patient and objective measures including body mass index (BMI), pulmonary function testing, electrocardiograms, and transthoracic echocardiography. The study was purely descriptive in design and provides only prevalence rates of specific abnormalities. The methodology of this study was limited. Although the case series establishes many potential explanations for patients’ symptoms of dyspnea, lower extremity edema, and other findings suggestive of CHF, it cannot establish which diagnosis is causing the symptoms without follow-up, comparison groups, or trials of treatment. This study also has other minor weaknesses: (1) lack of reporting of reasons for initial referral, or possible selection bias; (2) lack of attention to inter-rater reliability and quality of the echocardiography; and (3) lack of attention to confounding factors such as the variability of other cardiac evaluation and of the use of medications and other health interventions that might alter symptoms.
OUTCOMES MEASURED: Prevalence rates were reported for subjective symptoms, past medical problems, and objective measures of abnormal BMI, forced expiratory volume in 1 second (FEV1), electrocardiography, and echocardiography. The overlap of certain findings (obesity, respiratory disease, and cardiac abnormalities) were also assessed. The investigators made no attempts to measure costs, prognosis, response to therapy, functional status, quality of life, or patient satisfaction, all of which are important to assessing the value of this information in daily practice.
RESULTS: Most patients reported ankle swelling (68%) and dyspnea on exertion (92%). Fewer reported paroxysmal nocturnal dyspnea (23%) or dyspnea at rest (25%). Many had some previous medical condition (47% hypertension, 11% myocardial infarction, 28% angina, 6% coronary artery bypass graft, 23% pulmonary disease), and 81% were overweight or obese by BMI. Half of the patients had FEV1 measures less than 70% of predicted. After considering clinical history and electrocardiographic findings, 38% had evidence of coronary disease. Echocardiography detected signs of poor ventricular filling in 67% and left ventricular hypertrophy in 26% of all patients. Many patients had more than one abnormal finding. Only 7% of the patients had no abnormalities of BMI, respiratory, or coronary function.
This case series reports a high prevalence of diagnoses other than diastolic heart failure (including obesity, poor pulmonary function, and myocardial ischemia) in patients with preserved LV systolic function but symptoms suggestive of CHF. Since this descriptive study provides only prevalence rates, it does not establish the true cause for patients’ symptoms, but it should remind physicians of the broader differential diagnosis for symptoms they might otherwise assume to be due to diastolic dysfunction. Until evidence-based criteria for the diagnosis and treatment of diastolic dysfunction exists, clinicians should continue to pursue all possible cardiac or noncardiac causes for CHF-like symptoms.