Cardiovascular system: cardiac cycle, heart sounds, ECG
Physiology · MBBS
Beating heart
Interactive 3DA stylized heart pulsing at the rate you set, with its key chambers labelled.
Controls
Drag the sliders or type a value — the simulation updates live.
bpm
40bpm120bpm
Study notes
An ECG shows no P waves, just irregular wavy baseline with irregular QRS. This is atrial fibrillation — the atria quiver chaotically instead of contracting, so no P waves form, and the AV node lets through irregular impulses → irregularly irregular QRS. The quivering atria let blood stagnate and clot — clots can travel to the brain (stroke). Rate control plus blood thinners are the standard approach — rhythm facts driving treatment.
Related topics
- General physiology: cell, membrane transport, homeostasis
- Blood: RBC, hemoglobin, anemia basics, WBC, immunity basics
- Blood: platelets, hemostasis, coagulation, blood groups, transfusion
- Nerve and muscle: action potential, synapse, neuromuscular junction
- Nerve and muscle: muscle contraction, types of muscle fibers
- Cardiovascular system: hemodynamics, blood pressure regulation