rhythm-, rhythmo- +

(Greek: regularly recurring motion; measured motion)

accelerated idioventricular rhythm (s) (noun), accelerated idioventricular rhythms (pl)
A rapid ventricular rhythm, approximately 60 to 110 beats per minute: Accelerated idioventricular rhythm usually results from premature beats or an escape rhythm generated by the slowing of the sinus pacemaker or acceleration of a ventricular pacemaker.
1. A regular recurrence of a cardiac rhythm disturbance.
2. An irregular heartbeat that recurs repeatedly.
Characterized by allorhythmia.
alpha rhythm, alpha wave
1. A pattern of slow brain waves (alpha waves) in normal people at rest with closed eyes, thought by some to be associated with an alert but daydreaming mind.
2. The normal brainwave in the electroencephalogram of a person who is awake but relaxed.
3. A pattern of smooth, regular electrical oscillations in the human brain that occur when a person is awake and relaxed.

As recorded by the electroencephalograph, alpha waves have a frequency of 8 to 13 hertz.

An irregularity of the heart in which there is a lack of coordination between atrial and ventricular activity.
Irregular action of the heart, or absence of synchronism in the rate of atria and ventricles.
1. Preventing or alleviating cardiac arrhythmia.
2. An agent that prevents or alleviates cardiac arrhythmia.
Lacking a steady rhythm; such as, an arrhythmic heartbeat.
1. An abnormal rate of muscle contractions in the heart.
2. An irregularity in the rhythm of the heartbeat.

In an arrhythmia the heartbeats may be too slow, too rapid, too irregular, or too early.

Rapid arrhythmias (greater than 100 beats per minute) are called tachycardias. Slow arrhythmias (slower than 60 beats per minute) are called bradycardias. Irregular heart rhythms are called fibrillations (as in atrial fibrillation and ventricular fibrillation).

When a single heartbeat occurs earlier than normal, it is called a premature contraction.

3. Any variation from the normal rhythm of the heartbeat; it may be an abnormality of either the rate, regularity, or site of impulse origin or the sequence of activation.

The term encompasses abnormal regular and irregular rhythms as well as loss of rhythm.

arrhythmia (s) (noun), arrhythmias (pl)
Abnormal rates of muscle contractions or heart movements: With arrhythmias, a person's heartbeats may be too slow, too rapid, or very irregular.

Rapid arrhythmias (greater than 100 beats per minute) are called "tachycardias" while slow arrhythmias (slower than 60 beats per minute) are called "bradycardias"; and sometimes, irregular heart rhythms are called fibrillations or muscular twitching in the heart that involves individual muscle fibers that move without coordination.

Producing or promoting arrhythmia.
A dyskinesia consisting of a defective ability to perform voluntary successive movements of a definite rhythm.
Being without rhythm or regularity; such as, the pulse.
autopsychorhythmia (s) (noun), autopsychorhythmias (pl)
An abnormal rhythmic activity of the brain, once thought to be associated with insanity.
beta rhythm, beta wave
1. A pattern of electrical waves in the brain of someone who is awake and active.
2. In electroencephalography, a rapid rhythm usually of low voltage, which can be recorded in the motor areas of the brain and sometimes in the frontal regions; especially, during states of stress or anxiety or after the administration of certain drugs such as barbiturates.
3. The second most common waveform occurring in electroencephalograms of the adult brain, characteristically having a frequency from 13 to 30 cycles per second.

It is associated with an alert waking state but can also occur as a sign of anxiety or apprehension.