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  2. Heart sounds - Wikipedia

    en.wikipedia.org/wiki/Heart_sounds

    The first heart sound, or S 1, forms the "lub" of "lub-dub" and is composed of components M 1 (mitral valve closure) and T 1 (tricuspid valve closure). Normally M 1 precedes T 1 slightly. It is caused by the closure of the atrioventricular valves , i.e. tricuspid and mitral (bicuspid), at the beginning of ventricular contraction, or systole .

  3. T wave - Wikipedia

    en.wikipedia.org/wiki/T_wave

    Repolarization of the ventricle happens in the opposite direction of depolarization and is negative current, signifying the relaxation of the cardiac muscle of the ventricles. But this negative flow causes a positive T wave; although the cell becomes more negatively charged, the net effect is in the positive direction, and the ECG reports this ...

  4. Cardiac physiology - Wikipedia

    en.wikipedia.org/wiki/Cardiac_physiology

    The first heart sound S1, is the sound created by the closing of the atrioventricular valves during ventricular contraction and is normally described as "lub". The second heart sound, S2, is the sound of the semilunar valves closing during ventricular diastole and is described as "dub". [1]

  5. Heart - Wikipedia

    en.wikipedia.org/wiki/Heart

    The first heart sound S1, is the sound created by the closing of the atrioventricular valves during ventricular contraction and is normally described as "lub". The second heart sound, S2, is the sound of the semilunar valves closing during ventricular diastole and is described as "dub". [8]

  6. Cardiac cycle - Wikipedia

    en.wikipedia.org/wiki/Cardiac_cycle

    The section shows: 1) the opened ventricles contracting once per heartbeat—that is, once per each cardiac cycle; 2) the (partly obscured) mitral valve of the left heart; 3) the tricuspid and pulmonary valves of the right heart—note these paired valves open and close oppositely. + (The aortic valve of the left heart is located below the ...

  7. ST segment - Wikipedia

    en.wikipedia.org/wiki/ST_segment

    The typical ST segment duration is usually around 0.08 sec (80 ms). It should be essentially level with the PR and TP segments. The ST segment represents the isoelectric period when the ventricles are in between depolarization and repolarization.

  8. Systole - Wikipedia

    en.wikipedia.org/wiki/Systole

    Electrical waves track a systole (a contraction) of the heart. The end-point of the P wave depolarization is the start-point of the atrial stage of systole. The ventricular stage of systole begins at the R peak of the QRS wave complex; the T wave indicates the end of ventricular contraction, after which ventricular relaxation (ventricular diastole) begins.

  9. Atrioventricular node - Wikipedia

    en.wikipedia.org/wiki/Atrioventricular_node

    Isolated heart conduction system showing atrioventricular node. The AV node receives two inputs from the right atrium: posteriorly, via the crista terminalis, and anteriorly, via the interatrial septum. [8] Contraction of heart muscle cells requires depolarization and repolarization of their cell membranes. Movement of ions across cell ...