Table 4. GRADE tool for analysis of the level of evidence.

Certainty assessment							No. of patients		Effect		Certainty	Importance
No. of studies	Study design	Risk of bias	Inconsistency	Indirectness	Imprecision	Other considerations	Aerobic exercise	Control	Relative (95% CI)	Absolute (95% CI)
Fractional shortening (assessed with echocardiography and Doppler)
13	randomized trials	not serious	not serious	very seriousᵃ	not serious	none	230	222	–	mean 5.33% higher (3.4 to 7.26)	⨁⨁◯◯ Low	Critical
Left ventricular developed pressure (assessed with pressure transducer)
5	randomized trials	not serious	not serious	very seriousᵃ	not serious	none	153	166	–	mean 24.84 mm Hg higher (20.84 to 28.84)	⨁⨁◯◯ Low	Critical

CI: confidence interval; a: animal studies are considered indirect evidence.