Search results
Results from the WOW.Com Content Network
Sinus node dysfunction (SND), also known as sick sinus syndrome (SSS), is a group of abnormal heart rhythms (arrhythmias) usually caused by a malfunction of the sinus node, the heart's primary pacemaker. [1] [2] Tachycardia-bradycardia syndrome is a variant of sick sinus syndrome in which the arrhythmia alternates between fast and slow heart ...
Sinus node dysfunction also known as sick sinus syndrome is a group of irregular heartbeat conditions caused by faulty electrical signals of the heart. When the heart's sinoatrial node is defective, the heart's rhythms become abnormal—typically too slow or exhibiting pauses in its function or a combination, and very rarely faster than normal.
This sinus rhythm is important because it ensures that the heart's atria reliably contract before the ventricles, ensuring as optimal stroke volume and cardiac output. [ 4 ] In junctional rhythm, however, the sinoatrial node does not control the heart's rhythm – this can happen in the case of a block in conduction somewhere along the pathway ...
A syndrome of intrinsic disease of the sinus node, referred to as sick sinus syndrome or sinus node dysfunction, covers conditions that include symptomatic sinus bradycardia or persistent chronotropic incompetence, sinoatrial block, sinus arrest, and tachycardia-bradycardia syndrome. [2]
WPW syndrome may be monitored or treated with either medications or an ablation (destroying the tissues) such as with radiofrequency catheter ablation. [4] It affects between 0.1 and 0.3% in the population. [1] The risk of death in those without symptoms is about 0.5% per year in children and 0.1% per year in adults. [5]
Sinus activation and thus heart rate is regulated further through the autonomic nervous system. At rest, the sinus node is primarily regulated by tonic and phasic parasympathetic activation in normal, healthy individuals. Exercise causes vagal activation, sympathetic activation, and increases in catecholamine levels, which raises sinus rates.
For premium support please call: 800-290-4726 more ways to reach us
Human infectious diseases may be characterized by their case fatality rate (CFR), the proportion of people diagnosed with a disease who die from it (cf. mortality rate).It should not be confused with the infection fatality rate (IFR), the estimated proportion of people infected by a disease-causing agent, including asymptomatic and undiagnosed infections, who die from the disease.