sinus node การใช้

• A new selective sinus node inhibitor ivabradine is also being used to treat IST.
• This is mediated by the sympathetic nervous system on the sinus node and called sinus tachycardia.
• In hypertensive volunteers, like clonidine, it significantly increased sinus node recovery time and lowered cardiac output.
• Most conduction pathways originate from the cardiogenic mesoderm but the sinus node may be derived from the neural crest.
• Because the sinus node is rich in acetylcholinesterase, the effect of any vagal impulse is brief because the acetylcholine is rapidly hydrolyzed.
• Koch became known for his work on the motor centres of the human heart, and coined the term " sinus node ".
• The mechanism of the arrhythmia primarily involves the sinus node and peri-nodal tissue and does not require the AV node for maintenance.
• The impulse from the sinus node is still conducted via the internodal tracts to the AV node, and thus normal ventricular activation occurs.
• In atrial fibrillation, the regulation of electrical current at the sinus node is lost and impulses spread rapidly and repeatedly through the atria.
• Atrial premature complexes ( APCs ) do not have a compensatory pause since they reset the sinus node but atrial or supraventricular bigeminy can occur.
• The antiarrhythmic effects of beta blockers arise from sympathetic nervous system blockade resulting in depression of sinus node function and atrioventricular node conduction, and prolonged refractory periods.
• Some types of medication tried by cardiologists and other physicians include : beta blockers, selective sinus node I f channel inhibitors ( ivabradine ), calcium channel blockers and antiarrhythmic agents.
• Her P-waves, the small blips made when the sinus node fires, had disappeared; a natural backup pacemaker, nestled at the junction of the atria and the ventricles, had taken over.
• It is not possible, for example, to see on the ECG the sinus node activity, but the resulting atrial myocardium contraction is apparent as a wave  the P wave.
• Prolonged episodes of atrial fibrillation have been shown to correlate with prolongation of the sinus node recovery time, suggesting that dysfunction of the SA node is progressive with prolonged episodes of atrial fibrillation.
• Fibrosis is not limited to the muscle mass of the atria and may occur in the sinus node ( SA node ) and atrioventricular node ( AV node ), correlating with sick sinus syndrome.
• These cells are normally " paced " by regular electrical pulses from the heart's natural pacemaker, the sinus node, to ensure that they all contract together and that the two sets of chambers beat rhythmically.
• The " sinus node " at an upper area of the right atrium manages the pulses that flow through the two atria, causing the smaller heart chambers to contract and force blood into the larger ventricles.
• In particular sinus node dysfunction, atrial arrhythmias, ventricular arrhythmias including sudden cardiac arrhythmic death, heart failure due to anatomically right ventricular failure or venous obstruction at the level of the baffle or caval anatomy have been described.
• An important theory is that, in atrial fibrillation, the regular impulses produced by the sinus node for a normal heartbeat are overwhelmed by rapid electrical discharges produced in the atria and adjacent parts of the pulmonary veins.