Early research shows CRT may benefit patients with ejection fractions above 35%

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Early findings from a Medtronic sponsored study show heart failure patients with moderate ejection fractions, over 35%, may receive comparable benefits from cardiac resynchronization therapy (CRT) as compared to those with low ejection fractions of equal to or less than 35%.

A retrospective analysis from the PROSPECT (Predictors of response to CRT) study, the largest CRT post-market clinical study of its kind with primary endpoints measuring echocardiographic predictors of CRT response, suggests the potential for CRT to benefit more than 1 million heart failure patients worldwide who have an ejection fraction greater than 35% and are not currently indicated to receive CRT therapy.


“While more research is needed, this analysis shows the potential value of CRT for a broader spectrum of heart failure patients,” said Eugene Chung, director of the Heart Failure Program at The Christ Hospital, Ohio Heart and Vascular Center in Cincinnati, US, and lead investigator of the PROSPECT study. “Regardless of their ejection fraction, patients in this study had similar outcomes indicating ejection fraction alone may not be a good measure of a patient’s response to CRT.”


When compared at six months post implant, the CRT patients with moderate and severe heart failure and wide QRS duration had the following corresponding results.

  • Sixty-three percent of CRT patients with ejection fractions over 35% had an improved clinical composite response (based on vital status, NYHA changes, heart failure hospitalizations, patient assessments, and discontinuation of CRT), as compared to 70% in patients with ejection fractions at or below 35%.
  • Fifty-one percent of CRT patients with ejection fractions over 35% had a decrease in heart size (LVESV) greater than 15% as compared to 58% for those with ejection fractions at or below 35%.


A prospective, multicentre, non-randomised trial, PROSPECT enrolled 426 heart failure patients at 53 locations in Europe, the US and Hong Kong. The primary objective was to determine whether echocardiographic measures for mechanical left ventricular dyssynchrony could predict outcomes in patients receiving CRT. While some echo measures predicted statistically significant response, sensitivity and specificity were modest; in short, current guidelines for managing heart failure patients should be followed.


This retrospective analysis included 361 patients in the PROSPECT trial that had ejection fraction measured by the enrolling center and subsequently by an independent laboratory. The eligibility criteria for the trial included having a center-measured ejection fraction at or below 35 percent (as required for CRT indication). The independent laboratory showed that 86 of the 361 patients had an ejection fraction over 35% and 275 at or below 35%.

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