Complex sentence: Reduced left-heart filling leads to a reduced stroke volume which manifests as a decrease in systolic blood pressure which leads to a faster heart rate due to the baroreceptor reflex, which stimulates sympathetic outflow to the heart.
Split into simpler sentences: Reduced left-heart filling leads to a reduced stroke volume which manifests as a decrease in systolic blood pressure. The decrease in systolic blood pressure leads to a faster heart rate due to the baroreceptor reflex, which stimulates sympathetic outflow to the heart.