Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Rim Halaby, M.D. [2]; Mahmoud Sakr, M.D. [3] OverviewSinus arrhythmia is an irregularity of the sinus rhythm defined as a variation in the P-P interval by 0.16 sec (160 msec) or more in the presence of normal P waves. It is the most common type of arrhythmia and it is classified mainly into respiratory sinus arrhythmia and non-respiratory sinus arrhythmia. While respiratory sinus arrhythmia is a normal variant that is mostly common in young and disappears with age,[1] the non-respiratory sinus arrhythmia is most commonly present among elderly with heart disease. Sinus arrhythmia occurs with slower heart rates or after enhanced vagal tone, and tends to disappear with increase in the heart rate.[2] Triggers for sinus arrhythmia include sinoatrial block, sinus pause, premature atrial beat, carotid massage, and administration of parasympathomimetic medications. ClassificationRespiratory Sinus ArrhythmiaRespiratory sinus arrhythmia is associated with variations in the heart rate with the respiratory cycle secondary to changes in the vagal tone (heart rate increases in inspiration and decreases in expiration). It is a normal variant that is most present in young people. To read more about respiratory sinus arrhythmia, click here. Non-respiratory Sinus Arrhythmia
Ventriculophasic Sinus ArrhythmiaA ventriculophasic sinus arrhythmia occurs most often in patients with partial or complete AV block, but it's also observed after a compensatory pause induced by a premature ventricular contraction.[3] The P-P interval that does not contain the QRS complex is longer than that containing the QRS complex. Wandering of the Pacemaker within the SA NodeECG characteristics:
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What causes normal sinus arrhythmia?What causes sinus arrhythmia? It's not clear what causes people to develop a sinus arrhythmia. Researchers suspect that a connection between the heart, lungs, and vascular system may play a role. In older individuals, a sinus arrhythmia can occur as a result of heart disease or another heart condition.
What is the most common form of sinus arrhythmia?There are typically 2 types of sinus arrhythmia. By far the most common is basically benign and known as respiratory sinus arrhythmia. Here the variation in the heart rate is related to the breathing cycle.
What is normal sinus arrhythmia?For the most common type of sinus arrhythmia, the time between heartbeats can be slightly shorter or longer depending on whether you're breathing in or out. Your heart rate increases when you breathe in and slows down when you breathe out. This kind of arrhythmia is considered normal.
What age is sinus arrhythmia normal?Sinus arrhythmia defined as a range of 0.16 seconds or more is present under a year of age in both sexes. The range increases to a maximum between 8 and 12 years and only the 75th and 90th percentiles for boys show a definite decrease after this.
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