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Sinoatrial arrest

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Synonyms and keywords: sinus arrest; sinus pause

Overview

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Under certain circumstances, the SA node fails to initiate an impulse at the expected time in the cardiac cycle. In the absence of an impulse from the SA node, neither the atria nor the ventricles are stimulated and thus an entire PQRST complex drops out for 1 beat(or more). This is called sinoatrial (SA) arrest. In other instances the impulse is initiated normally but is blocked within the SA Node and never reaches the atria and ventricles. This is called sinus exit block or sinoatrial block. Sinus arrest is one of several variants of sinus node dysfunction. The word sinus pause is used to indicate a pause in the generation of QRS complexes for 3 seconds or less. If the delay is longer than this, then the term sinus arrest is used. If there is a markedly prolonged or permanent cessation of P wave and QRS complexes, then the term asystole is applied.

Pathophysiology

In sinoatrial arrest, the SA node is not generating electrical complexes due to impairment of automaticity. In patients with sinus arrest, the pause is more frequently associated with either an atrial or an AV junctional escape rhythm. If associated with sick sinus syndrome, lower pacemakers are impaired as well, therefore it can present as a complete absence of electrical activity on EKG.

Causes

Sinus arrest is fairly uncommon. It can be observed in the setting of myocardial disease (myocarditis) and ischemia or infarction (particularly acute inferior or posterior ST segment elevation MI). It can be a manifestation of digitalis or lidocaine toxicity.

Epidemiology and Demographics

Sinus arrest is fairly uncommon. It is more likely to be observed in elderly patients with a senescent rhythm system.

Diagnosis

Symptoms

If the AV junctional or ectopic ventricular pacemaker is not sufficiently rapid to generate an adequate cardiac output, then end organ hypoperfusion may result.

Laboratory Findings

Serum K+, Ca+ and Na+ should be checked as should thyroid function tests to rule out hypothyroidism.

References

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Historical Perspective

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References

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Pathophysiology

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Sinoatrial arrest (also known as sinus arrest or sinus pause) is a medical condition wherein the sinoatrial node of the heart transiently ceases to generate the electrical impulses that normally stimulate the myocardial tissues to contract and thus the heart to beat. It is defined as lasting from 2.0 seconds to several minutes.

Pathophysiology

In sinoatrial arrest, the SA node is not generating electrical complexes due to impairment of automaticity. In patients with sinus arrest, the pause is more frequently associated with either an atrial or an AV junctional escape rhythm. If associated with sick sinus syndrome, lower pacemakers are impaired as well, therefore it can present as a complete absence of electrical activity on EKG.

References

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Causes

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mugilan Poongkunran M.B.B.S [2]

Overview

Sinus arrest is fairly uncommon. It can be observed in the setting of myocardial disease (myocarditis) and ischemia or infarction (particularly acute inferior or posterior ST segment elevation MI). It can be a manifestation of digitalis or lidocaine toxicity.

Causes

Life Threatening Causes

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.

Common Causes

Causes by Organ System

Cardiovascular Acute coronary syndrome, acute rheumatic fever, Andersen cardiodysrhythmic periodic paralysis, Brugada syndrome, cardiac lymphoma, cardiac tumor, cardio inhibitory syncope, congenital heart disease, congestive heart failure, coronary reperfusion therapy, dilated cardiomyopathy, hypertensive heart disease, hypertrophic cardiomyopathy, ischemic heart disease, Jervell and Lange-Nielsen syndrome, long QT syndrome, myocardial infarction, myocardial rupture, myocarditis, NSTEMI, pericarditis, Romano-Ward syndrome, sick sinus syndrome, sinus bradycardia, sinus node fibrosis, STEMI, tachycardia-bradycardia syndrome, Timothy syndrome, valvular heart disease
Chemical / poisoning Berberine, grayanotoxin, organophosphate poisoning, parathion poisoning, pyrethroid poisoning, scorpion toxin
Dermatologic No underlying causes
Drug Side Effect Acetylcholine, alfentanil, amiodarone, anthracyclines, barbiturate, beta-blockers, bortezomib, bupivacaine, calcium channel blockers, cholinesterase inhibitors, clonidine, dexmedetomidine, digitalis, digoxin, diltiazem, donepezil, edrophonium, fentanyl, flecainide, granisetron, guanethidine, guanfacine, halothane, ibutilide, idarubicin, lacosamide, lidocaine, lithium, magnesium, mepivacaine, mesalamine, methyldopa, mexiletine, neostigmine, nitrous oxide, pentostatin, phenothiazine, phenytoin, procainamide, propafenone, propofol, pyridostigmine, quinidine, remifentanil, rescinnamine, reserpine, rilmenidine, ropivacaine, tacrine, thiamylal, vecuronium, verapamil
Ear Nose Throat No underlying causes
Endocrine Diabetic ketoacidosis, thyrotoxic periodic paralysis, pheochromocytoma, profound hypothyroidism
Environmental Berberine, hypothermia, poisonous spider bites, scorpion toxin
Gastroenterologic No underlying causes
Genetic Andersen cardiodysrhythmic periodic paralysis, Brugada syndrome, congenital heart disease, Emery-Dreifuss muscular dystrophy, Jervell and Lange-Nielsen syndrome, Kearns-Sayre syndrome, limb-girdle muscular dystrophy type 1B (LGMD1B), muscular dystrophy, myotonic dystrophy, Romano-Ward syndrome, Timothy syndrome
Hematologic Hemochromatosis, multiple myeloma
Iatrogenic Cardiac catheterization, cardiac transplantation, coronary artery bypass grafting, Fontan procedure, heart surgery, infraclavicular brachial plexus block, Maze procedure, post catheter ablation for arrhythmias
Infectious Disease Acute rheumatic fever, Chagas disease, diptheria, Lyme disease, myocarditis, pericarditis, septic shock, sarcoidosis, systemic lupus erythematosus, tuberculosis
Musculoskeletal / Ortho Muscular dystrophy, myotonic dystrophy, Timothy syndrome
Neurologic Carotid sinus hypersensitivity, lateral medullary syndrome, vagal reaction
Nutritional / Metabolic Hypermagnesemia, metabolic acidosis
Obstetric/Gynecologic No underlying causes
Oncologic Cardiac lymphoma, cardiac tumor, multiple myeloma, pheochromocytoma
Opthalmologic Sjogren’s syndrome
Overdose / Toxicity Acetylcholine, amiodarone, anthracyclines, barbiturate, bortezomib, cholinesterase inhibitors, digitalis, edrophonium, nitrous oxide, phenytoin, propofol
Psychiatric Takotsubo cardiomyopathy, severe anorexia nervosa
Pulmonary Hypoxia, sleep apnea
Renal / Electrolyte Acute renal failure, hyperkalemia
Rheum / Immune / Allergy Acute rheumatic fever, sarcoidosis, Sjogren’s syndrome, scleroderma
Sexual No underlying causes
Trauma Myocardial contusion, myocardial rupture, severe brain injury
Urologic No underlying causes
Dental No underlying causes
Miscellaneous Amyloidosis

Causes in Alphabetical Order

References

  1. Bailey PL (1990). “Sinus arrest induced by trivial nasal stimulation during alfentanil-nitrous oxide anaesthesia”. Br J Anaesth. 65 (5): 718–20. PMID 2248851.
  2. 2.0 2.1 2.2 Mills TA, Kawji MM, Cataldo VD, Pappas ND, O’Meallie LP, Breaux DM; et al. (2004). “Profound sinus bradycardia due to diltiazem, verapamil, and/or beta-adrenergic blocking drugs”. J La State Med Soc. 156 (6): 327–31. PMID 15688675.
  3. 3.0 3.1 Lines D, Shipton EA (1991). “Severe bradycardia and sinus arrest after administration of vecuronium, fentanyl and halothane. A case report”. S Afr Med J. 80 (4): 200–1. PMID 1678901.
  4. Bonvini RF, Hendiri T, Anwar A (2006). “Sinus arrest and moderate hyperkalemia”. Annales De Cardiologie Et D’angéiologie. 55 (3): 161–3. PMID 16792034. Unknown parameter |month= ignored (help)
  5. Koay S, Dewan B (2013). “An unexpected Holter monitor result: multiple sinus arrests in a patient with lateral medullary syndrome”. BMJ Case Rep. 2013. doi:10.1136/bcr-2012-007783. PMID 23386489.

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Differentiating Sinoatrial arrest from other Diseases

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References

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Epidemiology and Demographics

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

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Overview

Sinus arrest is fairly uncommon. It is more likely to be observed in elderly patients with a senescent rhythm system.

References

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Risk Factors

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References

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Natural History, Complications and Prognosis

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Diagnosis

Diagnosis

History and Symptoms | Physical Examination | Laboratory Findings | Electrocardiogram | Chest X Ray | Echocardiography | Other Imaging Findings | Other Diagnostic Studies

Treatment

Treatment

Medical Therapy | Surgery | Primary Prevention | Secondary Prevention | Cost-Effectiveness of Therapy | Future or Investigational Therapies

Case Studies

Case Studies

Case #1

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