Intersystolic Interval

The intersystolic interval (IISI) is the length of time between the end of one systolic phase and the beginning of the next systolic or diastolic phase of the cardiac cycle.

It involves the period when the heart relaxes after the end of the previous systolic phase, and then begins a new cycle of contraction. IISI is an important parameter for assessing the state of the cardiovascular system, since its deviation from the norm may indicate the presence of pathological processes in the myocardium or other organs and systems of the body. Normally, IISI is about 0.06-0.12 seconds, but if cardiac function is impaired, its duration increases and can reach several seconds.

IISI is measured using an electrocardiogram (ECG). Currently, IISI is measured using a research method called a “Holter ECG” - diagnostics are carried out using a portable device that is attached to the patient’s chest and takes data on heart rhythm throughout the day. This technology provides the clinician with a more accurate assessment of IISI and helps identify cardiac arrhythmias at the earliest stages of the disease.

Failure to comply with the interval is the cause of this phenomenon.

The intersystolic pause or simply "interval" is the time interval between each of the two halves of the heartbeat cycle.

The heartbeat cycle is a complex and individual process for each person. On average, its duration is about 720 milliseconds. It is divided into two phases - the myocardial interval (ST) and the diastolic interval (diastolic pressure).

The diastolic period is the relaxation phase during which the heart muscle fills with blood. The duration of diastole in normal people is about 45% of the total rhythm delay. For the fast-twitch pumps we call athletes, it can be longer than 7 seconds.

Myocardial erection is a period of strong contraction of the ventricles. It takes up about 35%, sometimes reaching 50% of the entire gap. This percentage varies depending on your heart rate and fitness.

Systolic voltage interval – more