Table 1.

Comparison of evidence base for evaluation and treatment of systolic versus diastolic heart failure

	Level of evidence*
Feature	Systolic heart failure	Diastolic heart failure
Prevalence and risk factors	III	III
Non-invasive diagnostic gold standard	Reduced ventricular ejection fraction (<0.50) on imaging	IV, VII (diagnosis by exclusion of systolic heart failure)
Prognosis	I-III	II, III
Treatment with angiotensin converting enzyme inhibitors, angiotensin receptor blockers, or β blockers	I (Cochrane review+meta-analyses)	II, V-VII
Prevention trials (treatment of asymptomatic precursor condition)	I	None

^*I: Evidence from several large, well conducted, randomised controlled trials; II: evidence from a single large, randomised controlled trial or small, well conducted randomised controlled trials; III: evidence from well conducted cohort studies; IV: evidence from well-conducted case-control studies; V: evidence from uncontrolled or poorly controlled studies; VI: conflicting evidence, but tending to favour the recommendation; VII: expert opinion.