The prevalence of left ventricular systolic dysfunction (LVSD) has declined over the last 30 years, and heart failure (HF) patients are increasingly demonstrating preserved ejection fraction versus reduced ejection fraction, according to a study published in JACC: Cardiovascular Imaging.

“Our observations over the last three decades suggest that secular trends in (cardiovascular disease) risk factors may be altering the profile of HF in the community,” lead author Ramachandran S. Vasan, MD, and colleagues wrote, estimating 75 percent of the observed shift toward HFpEF can be attributed to a lower prevalence of coronary heart disease and rising hypertension rates among heart failure patients.

Researchers analyzed trends from three decades of the Framingham Heart Study (1985 to 1994, 1995 to 2004 and 2005 to 2014). Individuals were included in the analysis if they received routine echocardiographic examinations and were under continuous surveillance for the development of heart failure during the study period.

Overall, Vasan et al. studied 12,857 patient observations. From the first decade of the study to the third, the prevalence of asymptomatic LVSD—left ventricular ejection fraction (LVEF) less than 50 percent—declined from 3.38 percent to 2.2 percent. Over that same span, the mean LVEF increased from 65 to 68 percent.

“This observation likely reflects the net balance between positive (rising burden of hypertension and obesity, and declining rates of smoking and total to high-density lipoprotein cholesterol ratio) and negative correlates of LVEF (increase in prevalence of diabetes and MI),” Vasan and coauthors wrote. “Improved management of MI and decline in the occurrence of ST-segment elevation MI may have also contributed. It is important to note that more than one-half of the change in mean LVEF remained unexplained, suggesting the need for additional study.”

Vasan et al. also analyzed the incidence of three types of heart failure: heart failure with reduced ejected fraction (HFrEF; EF less than 40 percent), heart failure with midrange ejection fraction (HFmrEF; EF between 40 and 50 percent) and heart failure with preserved ejection fraction (HFpEF; EF of at least 50 percent).

Among individuals newly diagnosed with heart failure over the 30-year period, HFpEF increased from 41 percent to 56.2 percent of cases. Meanwhile, HFrEF dropped from 44.1 to 31.1 percent, while HFmrEF didn’t change significantly (14.9 to 12.8 percent).

The authors also noted a 30 to 40 percent decline in cardiovascular mortality associated with HFrEF, but said survival didn’t change for the other heart failure diagnoses.

“The prognosis of HFmrEF and HFpEF remain largely unchanged over the 30-year period, identifying major areas for improvement,” they wrote. “Evidence-based management of patients with HFmrEF is challenged by the fact that they have not been consistently targeted in clinical trials and by the overall modest prevalence of the condition among HF patients (12 to 15 percent). Meta-analysis of data from controlled clinical trials of HF that enrolled patients with LVEF in the range 40 to 50 percent may inform future guidelines for managing these patients, and future clinical trials could consider pre-specifying this subgroup for analyses.”

Importantly, Framingham Heart Study included only middle-aged to elderly whites, limiting the generalizability to other patient groups.