Which factor is likely to worsen myocardial perfusion during cardiac events?

Increased heart rate can worsen myocardial perfusion during cardiac events due to a reduction in diastolic filling time. The heart relies on the diastolic phase of the cardiac cycle to receive blood supply from the coronary arteries. When the heart rate increases, the duration of diastole is shortened, which limits the time available for coronary blood flow. Since myocardial perfusion is crucial for delivering oxygen to the heart muscle, an elevated heart rate can lead to inadequate perfusion, particularly in the setting of coronary artery disease or other conditions that compromise blood flow. This highlights the relationship between heart rate and myocardial oxygen supply and demand dynamics during cardiac events.