Human heart rhythm is mainly regulated and controlled by the sinoatrial node. Fibrosis plays an important regulating role in adjusting the structural and functional integrity of the sinoatrial node pacemaker complex. In physiological state, the fibrosis degree of sinoatrial node is negatively correlated with heart rate, positively correlated with age and heart size, and can maintain a relatively stable heart rate. Pathological fibrosis of sinoatrial node can induce various types of arrhythmias which can result in sudden death. Determination of the mechanisms related to sinoatrial node pathological fibrosis could provide a target for clinical treatment of sinoatrial node fibrosis and diagnosis basis for forensic pathologists. This paper reviews the main mechanism of sinoatrial node pathological fibrosis, including abnormal activation of cardiac fibroblast cells in sinoatrial node, hyperplasia of epicardial adipose tissue, calcium clock disorder, artery stenosis, etc., introduces the test methods, diagnostic criteria as well as its role in sudden cardiac death and discusses the potential application, to provide reference for relevant research and application.
Arrhythmias, Cardiac ; Fibrosis ; Heart Rate ; Humans ; Sinoatrial Node

No abstract available.
Atrial Fibrillation ; Catheter Ablation ; Catheters ; Humans ; Sick Sinus Syndrome ; Sinoatrial Node

BACKGROUND AND OBJECTIVES: The objective of this study was to evaluate the long-term clinical outcomes and the incidence of permanent pacemaker implantation after catheter ablation in patients with of atrial fibrillation (AF) and sinus node dysfunction (SND).METHODS: Among 3,068 total consecutive patients who underwent AF catheter ablation (AFCA), this study included 222 (9.5%; men 53.2%, 63.7±9.2 years of age, 81.5% paroxysmal AF) with underlying SND and a regular rhythm follow-up. We analyzed the rhythm outcomes, changes in the mean heart rate or heart rate variability, and permanent pacemaker implantation rate.RESULTS: During 47.5±28.8 months of follow-up, 25 (11.3%) patients received pacemaker implantations due to symptomatic SND. More than half (56.0%, 14/25) underwent a pacemaker implantation within 3 months of the AFCA, and the annual pacemaker implantation rate was 2.0% afterwards. Both the early (68.0% vs. 31.0%, p<0.001) and clinical AF recurrence (68.0% vs. 32.5%, p=0.001) rates and continuous antiarrhythmic drug use after 3 months (44.0% vs. 24.4%, p=0.036) were significantly higher in patients requiring pacemaker implantations than those that did not. An anterior linear ablation (odds ratio [OR], 9.37 [3.03–28.9]; p<0.001) and the E/Em (OR, 1.15 [1.02–1.28]; p=0.018) were independently associated with permanent pacemaker implantations after AFCA in patients with AF and SND.CONCLUSIONS: After AFCA in patients with AF and SND, 1 of 9 patients needed a pacemaker implantation and half needed implantations within 3 months. The AF recurrence rate was significantly higher in those who required pacemaker implantations after the AFCA.
Atrial Fibrillation ; Catheter Ablation ; Catheters ; Follow-Up Studies ; Heart Rate ; Humans ; Incidence ; Male ; Pacemaker, Artificial ; Recurrence ; Sick Sinus Syndrome ; Sinoatrial Node

The electrical impulses of atrium arise from the sinus node, subsequently pass through the right and left atrium, and finally arrive at the atrioventricular node. The P wave is the summation of the electrical current generated by depolarization due to its passage through the atrial conduction pathway. It provides many clinical clues that may be useful for diagnosis of atrial, ventricular, or valvular heart diseases. This review article briefly describes the clinical implications, mechanism of genesis, and normal and pathologic features of the P wave.
Atrioventricular Node ; Diagnosis ; Heart Atria ; Heart Valve Diseases ; Sinoatrial Node

The incidence of intraoperative arrhythmia is extremely high, and some arrhythmias require clinical attention. Therefore, it is essential for the anesthesiologist to evaluate risk factors for arrhythmia and understand their etiology, electrophysiology, diagnosis, and treatment. Anesthetic agents reportedly affect normal cardiac electrical activity. In the normal cardiac cycle, the sinoatrial node initiates cardiac electrical activity through intrinsic autonomous pacemaker activity. Sequential atrial and ventricular contractions result in an effective cardiac pumping mechanism. Arrhythmia occurs due to various causes, and the cardiac pumping mechanism may be affected. A severe case may result in hemodynamic instability. In this situation, the anesthesiologist should eliminate the possible causes of arrhythmia and manage the condition, creating hemodynamic stability under proper electrocardiographic monitoring.
Anesthesia ; Anesthetics ; Arrhythmias, Cardiac* ; Diagnosis ; Electrocardiography ; Electrophysiology ; Hemodynamics ; Incidence ; Risk Factors ; Sinoatrial Node

Sinus tachycardia is an accelerated rhythm in which the rate of impulses arising from the sinoatrial node is elevated. Uncontrolled sinus tachycardia may result in a poor prognosis, particularly in patients with cardiovascular disease, because of a hemodynamic disturbance arising from the tachycardia itself. When sinus tachycardia is specifically triggered by anemia, shock, or fever, it is referred to as physiological sinus tachycardia. Physiological sinus tachycardia should resolve with correction of the underlying cause. Inappropriate sinus tachycardia (IST) is unexplained by physiological demand. Palpitation is the most frequent symptom in IST patients. Even though treatment of IST has insufficient efficacy and a relatively high recurrence rate, several treatment strategies such as use of a β-blocker, ivabradine, and radiofrequency catheter ablation can be used for IST patients.
Anemia ; Arrhythmia, Sinus ; Cardiovascular Diseases ; Catheter Ablation ; Fever ; Hemodynamics ; Humans ; Prognosis ; Recurrence ; Shock ; Sinoatrial Node ; Tachycardia* ; Tachycardia, Sinus

Heart rate variability (HRV) is the difference between the successive changes in the heartbeat cycle, and it is produced in the autonomic nervous system modulation of the sinus node of the heart. The HRV is a valuable indicator in predicting the sudden cardiac death and arrhythmic events. Traditional analysis of HRV is based on a multielectrocardiogram (ECG), but the ECG signal acquisition is complex, so we have designed an HRV analysis system based on photoplethysmography (PPG). PPG signal is collected by a microcontroller from human's finger, and it is sent to the terminal via USB-Serial module. The terminal software not only collects the data and plot waveforms, but also stores the data for future HRV analysis. The system is small in size, low in power consumption, and easy for operation. It is suitable for daily care no matter whether it is used at home or in a hospital.
Autonomic Nervous System ; physiopathology ; Cardiovascular Diseases ; diagnosis ; Death, Sudden, Cardiac ; Electrocardiography ; Heart Rate ; Humans ; Monitoring, Ambulatory ; instrumentation ; Photoplethysmography ; instrumentation ; Sinoatrial Node ; physiopathology ; Software

Hyponatremia is the most common electrolyte abnormality in hospitalized patients and often presents no symptoms. The association between sinus node dysfunction and hyponatremia has rarely been reported. We describe a 77-year-old woman who developed reversible sinus node dysfunction accompanied by pulmonary edema that was associated with hyponatremia.
Aged ; Female ; Humans ; Hyponatremia* ; Pulmonary Edema* ; Sick Sinus Syndrome* ; Sinoatrial Node*

Sinoatrial node (SAN) automaticity is jointly regulated by a voltage (cyclic activation and deactivation of membrane ion channels) and Ca2+ clocks (rhythmic spontaneous sarcoplasmic reticulum Ca2+ release). Using optical mapping in Langendorff-perfused canine right atrium, we previously demonstrated that the beta-adrenergic stimulation pushes the leading pacemaker to the superior SAN, which has the fastest activation rate and the most robust late diastolic intracellular calcium (Cai) elevation. Dysfunction of the superior SAN is commonly observed in animal models of heart failure and atrial fibrillation (AF), which are known to be associated with abnormal SAN automaticity. Using the 3D electroanatomic mapping techniques, we demonstrated that superior SAN served as the earliest atrial activation site (EAS) during sympathetic stimulation in healthy humans. In contrast, unresponsiveness of superior SAN to sympathetic stimulation was a characteristic finding in patients with AF and SAN dysfunction, and the 3D electroanatomic mapping technique had better diagnostic sensitivity than corrected SAN recovery time testing. However, both tests have significant limitations in detecting patients with symptomatic sick sinus syndrome. Recently, we reported that the location of the EAS can be predicted by the amplitudes of P-wave in the inferior leads. The inferior P-wave amplitudes can also be used to assess the superior SAN responsiveness to sympathetic stimulation. Inverted or isoelectric P-waves at baseline that fail to normalize during isoproterenol infusion suggest SAN dysfunction. P-wave morphology analyses may be helpful in determining the SAN function in patients at risk of symptomatic sick sinus syndrome.
Adrenergic beta-Agonists ; Atrial Fibrillation ; Biological Clocks ; Calcium ; Heart Atria ; Heart Failure ; Humans ; Isoproterenol ; Membranes ; Models, Animal ; Sarcoplasmic Reticulum ; Sick Sinus Syndrome ; Sinoatrial Node*

Paroxysmal atrial fibrillation may be induced by coronary spasm presenting with typical angina-like pain and palpitations. It is typically treated using rate or rhythm control strategies, although sustained coronary spasm can induce sinus bradycardia with dizziness and syncope. In the present case, we reached a diagnosis of paroxysmal atrial fibrillation and sinus bradycardia due to coronary artery spasm using the methyl-ergonovine provocation test during angiography. While the treatment of coronary spasm can resolve paroxysmal atrial fibrillation, sinus bradycardia, and variant angina, the mechanism remains unclear, although it may be associated with sinus node ischemia. Similar symptoms, particularly chest discomfort, should be carefully considered in cases of paroxysmal atrial fibrillation.
Angiography ; Atrial Fibrillation* ; Bradycardia* ; Coronary Vasospasm ; Coronary Vessels* ; Diagnosis ; Dizziness ; Ischemia ; Sinoatrial Node ; Spasm* ; Syncope ; Thorax