Sinus arrest primarily affects older patients [1]. It may arise either as a manifestation of sinus node dysfunction, as a side effect from certain drugs used to treat cardiovascular diseases (eg. digitalis), as a complication of myocardial ischemia or sleep apnea, and alongside a fibrotic sinoatrial node condition [2] [3].

Depending on whether the arrest lasts for 2 seconds or for a longer period of time, sinus arrest causes symptoms ranging from mild/unnoticed to severe and life-threatening. Patients diagnosed with the condition usually belong to the senior age group and exhibit various comorbidities. The most common manifestations associated with sinus arrest include syncope, light-headedness, loss of orientation, weakness, angina, and heart failure [4] [5] [6]. Loss of consciousness experienced by a patient due to sinus arrest is known as Adam-Stokes attack. Oliguria may also complicate the clinical picture.

Sinus arrest during periictal period has been observed by a study to frequently arise in patients with inadequately controlled epilepsy [7]. In a typical sinus arrest case, should the electrical activity be paused for too long, different cellular groups will undertake the pacemaking responsibility until the sinoatrial node recovers. If that does not happen, sinus arrest can lead to hypoxia, multiple organ system failure, and cardiac arrest.

• Crying

  The seizures occurred after crying, pain, or frustration. [ahajournals.org]

• Hypoxemia

  Transient bradycardia in the critical care setting is frequently caused by hypoxemia or oropharyngeal manipulation. [ncbi.nlm.nih.gov]

• Hiccup

  We describe asymptomatic sinus arrest and post-hiccup cough syncope in a patient with medullary infarction. A 78-year-old woman developed arrhythmia, hiccup, and cough syncope attacks. Neurological examination was not remarkable. [ncbi.nlm.nih.gov]

• Heart Disease

  Vasovagal syncope following exercise in the absence of structural heart disease is uncommonly reported. [ncbi.nlm.nih.gov]

• Skipped Beats

  Patients who have sinus pauses may complain of missed or skipped beats, flutters, palpitations, hard beats or may feel faint, dizzy or lightheaded or experience a syncopal episode (passing out). Frequent pauses would heighten these symptoms. [equimedcorp.com]

• Slow Pulse

  Symptoms of SSS include: fainting or fainting sensations fatigue dizziness palpitations (abnormal heart beats) very slow pulse (bradycardia) difficulty breathing chest pain mental confusion memory problems disrupted sleep It’s important to see your doctor [healthline.com]

• Polyradiculoneuropathy

  Guillain-Barre syndrome, or acute inflammatory demyelinating polyradiculoneuropathy, is frequently accompanied by cardiac and autonomic dysfunction. [jhu.pure.elsevier.com]

  Abstract Guillain-Barre syndrome, or acute inflammatory demyelinating polyradiculoneuropathy, is frequently accompanied by cardiac and autonomic dysfunction. [neurology.org]

• Catatonia

  We report a case of neuroleptic malignant syndrome where the catatonia clearly followed the administration of neuroleptics and where the neurovegetative disturbance was remarkably severe, including episodes of tracheal spasm, apnoea and episodes of bradycardia [ncbi.nlm.nih.gov]

• Exercise-Induced Syncope

  The unusual nature of the diagnosis offers an opportunity to review the mechanism of vasovagal as well as exercise-induced syncope. [casereports.bmj.com]

Sinus arrest is detected via a 12-lead electrocardiogram. Senior individuals who present with symptoms possibly originating from the cardiovascular system, such as angina, loss of consciousness, and fatigue, should always undergo an electrocardiographic evaluation.

A typical sinus arrest electrocardiogram (ECG) will reveal an absence of P waves, with a duration ≥ 2 seconds. Of note, the length of the pause cannot be expressed as a multiple of the basic sinus cycle length. Occasionally and when the P waves are absent for a relatively long time, escape beats appear, as other groups of myocardial cells undertake the pacemaking process for a brief period of time. The R-R interval before and after sinus arrest is stable.

Given that sinus arrest occurs as a result of sinus node dysfunction, myocardial ischemia, certain drugs, and other causes, these need to be investigated as well. Laboratory tests can illustrate a potential hyperkalemia, the ECG will also diagnose ongoing ischemic alterations of the myocardium, and ambulatory or long-term ECG monitoring can also be employed in order to investigate the presence of an underlying pathology and confirm where the symptoms originate from [8].

• Dyslipidemia

  Case presentation A 56-year-old woman with a significant history of RCA stenosis with prior bare metal stenting, hypertension, diabetes, dyslipidemia, smoking, and paroxysmal atrial fibrillation presented to the emergency department with anginal chest [intarchmed.biomedcentral.com]

• P Wave Absent

  Ventricular Fibrillation (VF) Video licensed from Rate: rapid and disorganized Rhythm: irregular and chaotic P Wave: absent but can be recognizable PRI: not measurable QRS: fibrillatory waves; wide irregular oscillations of the baseline. [ceufast.com]

  P waves: absent, irregular fibrillation waves seen instead 5. PR interval: not measurable 6. Interpretation: Atrial Fibrillation a) If ventricular rate is 100, called uncontrolled A-fib b) If ventricular rate is 100, called controlled A-fib G. [andrews.edu]

1. Pikkujamsa SM, Makikallio TH, Sourander LB, et al. Cardiac interbeat interval dynamics from childhood to senescence: comparison of conventional and new measures based on fractals and chaos theory. Circulation. 1999;100(4):393–399.
2. Csepe TA, Kalyanasundaram A, Hansen BJ, Zhao J, Fedorov VV. Fibrosis: a structural modulator of sinoatrial node physiology and dysfunction. Front Physiol. 2015; 6: 37.
3. Alonso A., Jensen P. N., Lopez F. L., et al. Association of sick sinus syndrome with incident cardiovascular disease and mortality: the atherosclerosis risk in communities study and cardiovascular health study. PLoS ONE. 2014;9:e109662.
4. Olshansky B, Chung MK, Pogwizd SM, Goldschlager N. Arrhythmia Essentials. Philadelphia, PA: Elsevier; 2016. ISBN: 9780323399685
5. Ferrer MI, MD. Disturbances in sinus rhythm: sinus arrest, sino-atrial exit block. J Insur Med. 1994; 26(3):360-361.
6. New York Heart Association. Criteria Committee.Nomenclature and criteria for diagnosis of diseases of the heart and great vessels. Criteria, 8th ed. Boston, MA: Little Brown & Co., Boston;1979.
7. Zipes DP. Cardiac Electrophysiology: From Cell to Bedside. Philadelphia, PA. Elsevier; 2014. ISBN: 9781455728565
8. Crawford MH, Bernstein SJ, Deedwania PC, et al. ACC/AHA guidelines for ambulatory electrocardiography. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Revise the Guidelines for Ambulatory Electrocardiography). Developed in collaboration with the North American Society for Pacing and Electrophysiology. J Am Coll Cardiol. 1999;34 (3):912-948.