Sinoauricular node disease

It refers to a syndrome characterized by the successive or simultaneous appearance of numerous arrhythmias , caused by an alteration in the functioning of the NSA and, to a lesser extent, the rest of the structures of the specific system of generation and conduction of the cardiac impulse .

Electrocardiographic characteristics

They are defined by the accompanying arrhythmias :

  • Sinus bradycardia

It is the most common and earliest manifestation; It is usually persistent, without significant variations during exercise or administration of atropine, and sometimes severe. Alterations of the P wave may occur, characterized by changes in the electrical axis and the configuration of the wave, without variations in the PR interval or duration of the cycles, expression of intra-atrial conduction disorders

  • Pauses sinus by blocking or stoppage SA

They constitute the most specific manifestation of the indicated syndrome .

  • AV junction disorders

They can lead to longer, symptomatic sinus pauses , and escape rates, if they occur, are significantly bradycardial . Variable-grade AV blocks may be present , usually first-degree.

  • Intraventricular conduction disorders

Especially from the anterior bundle of the left branch.

  • Other atrial and ventricular arrhythmias

They are frequent and occur paroxysmally; alternate with the reported slow rhythms – bradycardia-tachycardia syndrome . The most common is the fibrillation atrial , but there may be atrial flutter, tachycardia paroxysmal supraventricular – reentrant, and more specifically of the NSA-, tachycardia nonparoxysmal AV junction; as well as atrial and ventricular premature complexes , and ventricular tachycardia .

  • Slow ventricular response

It is characteristic during tachycardias , due to AV block, and abnormally long pauses after a salvo of tachycardia or an early stimulus.

Clinical features

It has an organic base, although a group of medicines , with antiarrhythmic action or not, can precipitate or aggravate its manifestations. It is observed more frequently in older adults , but it can occur in young people , and even children , associated with specific causes. The patients may be asymptomatic; the symptoms are nonspecific and depend on the duration of the pauses, the previous state of the cerebral circulation and the presence of the temporary tachyarrhythmia crises . Include palpitations , dizziness , fatigue, alterations of the intellectual capacity, syncope, presyncope, heart failure and angina .


It is related to the basic rhythm disorder and associated clinical manifestations, which must be attributed to the syndrome , in order for it to be justified. The bradycardia isolated with few symptoms may improve with administration of aminophylline . Patients with more severe symptoms are candidates for implantation of a permanent pacemaker . On the other hand, temporary rapid arrhythmias cannot be treated with specific drugs without adequate protection from a PM, a measure with which the symptoms often disappear .


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