S4 gallop occurs during which phase of the cardiac cycle?

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Multiple Choice

S4 gallop occurs during which phase of the cardiac cycle?

S4 gallop is produced when the atria contract against a stiff, noncompliant ventricle. This happens in late diastole, during atrial systole, just before the ventricles begin to contract. The forceful atrial kick into a rigid ventricle creates a vibration that you hear as the fourth heart sound. It’s commonly heard with reduced LV compliance (like LV hypertrophy, aging, or diastolic dysfunction). It’s not heard during ventricular systole, isovolumetric relaxation, or early diastole, since those times involve ventricular contraction, closed valves with no atrial kick, or rapid passive filling, respectively.

S4 gallop is produced when the atria contract against a stiff, noncompliant ventricle. This happens in late diastole, during atrial systole, just before the ventricles begin to contract. The forceful atrial kick into a rigid ventricle creates a vibration that you hear as the fourth heart sound. It’s commonly heard with reduced LV compliance (like LV hypertrophy, aging, or diastolic dysfunction). It’s not heard during ventricular systole, isovolumetric relaxation, or early diastole, since those times involve ventricular contraction, closed valves with no atrial kick, or rapid passive filling, respectively.

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