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Fetal heart rate monitoring. 30 weeks pregnancy. The human heart beats more than 2.8 billion times in an average lifetime. [60] The heartbeat of a human embryo begins at approximately 21 days after conception, or five weeks after the last normal menstrual period (LMP), which is the date normally used to date pregnancy in the medical community.
In this example there are 1000 pulses per second (one kilohertz pulse rate) with a gated pulse width of 42 μs. The pulse packet frequency in this example is 27.125 MHz of RF energy. The duty cycle for a pulsed radio frequency is the percent time the RF packet is on, 4.2% for this example ([0.042 ms × 1000 pulses divided by 1000 ms/s] × 100).
Electromagnetic (e.g. radio or light) waves are conceptually pure single frequency phenomena while pulses may be mathematically thought of as composed of a number of pure frequencies that sum and nullify in interactions that create a pulse train of the specific amplitudes, PRRs, base frequencies, phase characteristics, et cetera (See Fourier Analysis).
A child aged 1–3 years old can have a heart rate of 80–130 bpm, a child aged 3–5 years old a heart rate of 80–120 bpm, an older child (age of 6–10) a heart rate of 70–110 bpm, and an adolescent (age 11–14) a heart rate of 60–105 bpm. [12] An adult (age 15+) can have a heart rate of 60–100 bpm. [12]
There are two atrial and two ventricle chambers of the heart; they are paired as the left heart and the right heart—that is, the left atrium with the left ventricle, the right atrium with the right ventricle—and they work in concert to repeat the cardiac cycle continuously (see cycle diagram at right margin). [1]
Heart rate variability visualized with R-R interval changes Electrocardiogram (ECG) recording of a canine heart that illustrates beat-to-beat variability in R–R interval (top) and heart rate (bottom). Heart rate variability (HRV) is the physiological phenomenon of variation in the time interval between heartbeats. It is measured by the ...
The two beats are figuratively similar to two twins (hence bi-+ gemini). For example, in ventricular bigeminy, a sinus beat is shortly followed by a premature ventricular contraction (PVC), a pause, another normal beat, and then another PVC. [1] In atrial bigeminy, the other "twin" is a premature atrial contraction (PAC).
In medicine, the pulse is the rhythmic throbbing of each artery in response to the cardiac cycle (heartbeat). [1] The pulse may be palpated in any place that allows an artery to be compressed near the surface of the body, such as at the neck (carotid artery), wrist (radial artery or ulnar artery), at the groin (femoral artery), behind the knee (popliteal artery), near the ankle joint ...