sinus rhythm


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rhythm

 [rith´m]
a measured movement; the recurrence of an action or function at regular intervals. adj., adj rhyth´mic, rhyth´�mical.
accelerated idiojunctional rhythm a junctional rhythm, without retrograde conduction to the atria, at a rate exceeding the normal firing rate of the junction; it is an ectopic rhythm located in the bundle of His and controlling ventricles at a rate of 60 to 100 beats per minute.
accelerated idioventricular rhythm a rhythm of ectopic ventricular origin, faster than the normal rate of the His-Purkinje system but slower than 100 beats per minute, without retrograde conduction to the atria.
accelerated junctional rhythm a rhythm emanating from a focus in the AV junction at a rate greater than its normal rate of 60 but less than 100 beats per minute; it may be due to altered automaticity secondary to disease or to triggered activity secondary to digitalis toxicity. There may or may not be retrograde conduction to the atria.
alpha rhythm uniform rhythm of waves in the normal electroencephalogram, showing an average frequency of 10 per second, typical of a normal person awake in a quiet resting state. Called also Berger rhythm. See also electroencephalography.
atrioventricular junctional rhythm a junctional rhythm originating in the bundle of His, with a heart rate of 40 to 60 beats per minute; called also nodal rhythm.
automatic rhythm spontaneous rhythms initiated by the sinoatrial node, or by subsidiary atrial or ventricular pacemakers; in practice this refers to a normal sinus rhythm at a rate of 60 to 100 beats per minute.
Berger rhythm alpha rhythm.
beta rhythm a rhythm in the electroencephalogram consisting of waves smaller than those of the alpha rhythm, having an average frequency of 25 per second, typical during periods of intense activity of the nervous system. See also electroencephalography.
biological r's the cyclic changes that occur in physiological processes of living organisms; these rhythms are so persistent in nature that they probably should be considered a fundamental characteristic of life, as are growth, reproduction, metabolism, and irritability. Many of the physiological processes that recur in humans about every 24 hours (with circadian rhythm) have been known for centuries. Examples include the peaks and troughs seen in body temperature, vital signs, brain function, and muscular activity. Biochemical analyses of urine, blood enzymes, and plasma serum also have demonstrated circadian rhythms. Called also biorhythms.



It has long been believed that the cyclic changes observed in plants and animals were totally in response to environmental changes and, as such, were exogenous or of external origin. This hypothesis has now been rejected by most chronobiologists, who hold that the biological rhythms are intrinsic to the organisms, and that the organisms possess their own physiological mechanism for keeping time. This mechanism has been called the “biological clock.” An example of adjustment of the biological clock in humans is recovery from “jet lag.” This phenomenon, also known as jet syndrome, occurs when humans are transported by jet plane across time zones. It is characterized by fatigue and lowered efficiency, which persist until the biological clock adjusts to the new environmental cycle.

Biological rhythms are responsive to, or synchronous with, environmental cycles, but it is generally agreed among chronobiologists that the rhythmic changes in environmental factors do not create biological rhythms, even though they are capable of influencing them. Even in the absence of such environmental stimuli as light, darkness, temperature, gravity, and electromagnetic field, biological rhythms continue to maintain their cyclic nature for a period of time.
circadian rhythm the regular recurrence in cycles of about 24 hours from one point to another, such as certain biological activities that do this regardless of long periods of darkness or other changes in environmental conditions.
circamensual rhythm recurrence in cycles of about one month (30 days).
circannual rhythm recurrence of a phenomenon in cycles of about one year.
circaseptan rhythm that which occurs in cycles of about seven days (one week).
coupled rhythm heart beats occurring in pairs, the second beat of the pair usually being a ventricular premature beat.
delta rhythm
1. electroencephalographic waves having a frequency below 3½ per second, typical in deep sleep, in infancy, and in serious brain disorders. See also electroencephalography.
2. delta waves.
escape rhythm a heart rhythm initiated by lower centers when the sinoatrial node fails to initiate impulses, its rhythmicity is depressed, or its impulses are completely blocked.
gallop rhythm an auscultatory finding of three or four heart sounds, created by gushes of blood entering resistant or stiffened ventricles. This can happen at two different times during ventricular diastole: either at initial filling or at the time of ventricular contraction. Therefore, gallops occur during early and late ventricular diastole.
gamma rhythm a rhythm in the waves in the electroencephalogram having a frequency of 50 per second. See also electroencephalography.
idiojunctional rhythm a rhythm emanating from the atrioventricular junction but without retrograde conduction to the atria.
infradian rhythm the regular recurrence in cycles of more than 24 hours, as certain biological activities which occur at such intervals, regardless of conditions of illumination or other environmental conditions.
junctional rhythm an arrhythmia caused by an abnormality in the atrioventricular junction; see accelerated junctional rhythm and atrioventricular junctional rhythm.
rhythm method old popular name for natural family planning.
nyctohemeral rhythm a day and night rhythm.
pendulum rhythm alternation in the rhythm of the heart sounds in which the diastolic sound is equal in time, character, and loudness to the systolic sound, the beat of the heart resembling the tick of a watch.
sinus rhythm normal heart rhythm originating in the sinoatrial node, with a normal rate of 60 to 100 beats per minute.
theta rhythm electroencephalographic waves having a frequency of 4 to 7 per second, occurring mainly in children but also in adults under emotional stress. See also electroencephalography.
ultradian rhythm the regular recurrence in cycles of less than 24 hours, as certain biological activities which occur at such intervals, regardless of conditions of illumination or other environmental conditions.
ventricular rhythm the ventricular contractions which occur in cases of complete heart block.

si·nus rhyth·m

normal cardiac rhythm proceeding from the sinoatrial node; in healthy adults its rate is 60-90 beats/min.

sinus rhythm

n.
A normal cardiac rhythm proceeding from the sinoatrial node.

si·nus rhythm

(sī'nŭs ridh'ŭm)
Normal cardiac rhythm proceeding from the sinuatrial node.
References in periodicals archive ?
In this study, we aimed to investigate the role of CT-1 in AF remodeling and whether CT-1 can be used as a predictor of sinus rhythm maintenance among persistent AF patients converted to sinus rhythm via electrical CV.
In other patients with only mild symptoms the decision to recommend cardioversion can be assisted by the knowledge that there is a high expectation of restoring and maintaining sinus rhythm. We describe here a protocol[10] derived from the available literature[11-13] and from clinical experience, which can be applied to these patients to select a group where the physician can be confident of success.
The average postoperative follow-up time was (28.2+-23.7) months; the maintenance rate of sinus rhythm was 92.4% two years after surgery, among which 82.8% of them were patients with sinus rhythm who stopped taking anti-arrhythmia agent.
Galve Eet al.12 suggested that intravenous amiodarone, at the doses used in their study, produces a modest but not significant benefit in converting acute AF to sinus rhythm.In our study, follow-up was shorter, therefore, comparable results could not be defined.
Sedative drugs (diazepam or midazolam) and low molecular weight heparin (enoxaparin) were started and continued until the sinus rhythm and effective atrial contractions could be obtained.
The prescribing information for dronedarone has been revised to reflect the results of the safety review, and now advises against prescribing dronedarone to patients with AF "who will not or cannot be converted into normal sinus rhythm," because "it doubles the rate of cardiovascular death, stroke, and heart failure in such patients." The label also recommends an electrocardiogram to monitor heart rhythm in patients on the drug "at least once every three months," and if a patient is in AF, treatment should be stopped or, "if clinically indicated," the patient should be cardioverted.
In this particular case, it even enabled conversion to normal sinus rhythm during the ablation of the right superior pulmonary vein.
If the Afib does not stop on its own, your doctor may use antiarrhythmic drugs or electrical cardioversion to return the heart to normal sinus rhythm. Afterward, antiarrhythmics--such as amiodarone (Cordarone, Pacerone), sotalol (Betapace), dofetilide (Tikosyn), flecainide (Tambocor), propafenone (Rythmol) and, most recently, dronedarone (Multaq)--can help maintain normal sinus rhythm, but they have side effects ranging from fatigue and nausea to liver and thyroid disorders and dangerous ventricular arrhythmias.
Maintenance of sinus rhythm in patients with atrial fibrillation: an AFFIRM substudy of the first antiarrhythmic drug.
According to the company, it has two marketed, in-hospital, cardiology products, BRINAVESS (vernakalant IV), approved in Europe and other territories for the rapid conversion of recent onset atrial fibrillation to sinus rhythm in adults, as well as AGGRASTAT (tirofiban HCl) a reversible GP IIb/IIIa inhibitor indicated for use in patients with acute coronary syndrome.
DIAGNOSIS: Normal sinus rhythm; left atrial enlargement.