You determine a patients heart rate to be 48 beats/min. that heart rate would be categorized as:

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Each year millions of people experience abnormal heart rhythms (arrhythmias), which are common as we age. For most, a normal resting heart rate is 60 to 100 beats per minute (bpm). For athletic individuals, a normal resting heart rate may be as low as 40 to 60 bpm. Abnormal heart rhythms can be described as a heart beating too fast (above 100 bpm) or slow (below 60 bpm), a fluttering sensation in the chest area or the skipping of a heart beat. When electrical impulses in the heart become too fast, too slow, or irregular they cause the heart to beat irregularly.

Abnormal heart rhythms may cause the heart to pump blood inefficiently causing poor blood circulation in the body. As a result, less oxygen reaches other parts of the body and can cause organ damage. In most cases, abnormal heart rhythms are harmless, however, some cases may cause uncomfortable symptoms like dizziness, palpitations, pounding in the chest, fainting, shortness of breath, weakness, or fatigue. If some types of abnormal heart rhythms are left untreated, they may even cause sudden cardiac death.

Types

Main types of arrhythmia include:

Bradycardia – The heart beats too slow, below 60 bpm. For athletic individuals, a normal resting heart rate can be below 60 bpm, and not cause problems. Bradycardia is caused by a disruption of the electrical impulses conducted by the heart. Aging, hypothermia, damage from a heart attack or heart disease, and other factors can contribute to the disruption of impulses.

Tachycardia – The heart beats too fast, above 100 bpm. Tachycardia is caused by a disruption of the electrical impulses conducted by the heart. Damage from a heart attack or heart disease, congenital heart disease, high blood pressure, smoking and other factors can contribute the disruption of impulses.

  • Atrial or Supraventricular Tachycardias – Occurs either in the upper chambers (atria) or the middle region.
  • Sinus Tachycardia – A correctly functioning heart with a faster heart rate.
  • Ventricular Tachycardias – Occurs in the lower chambers of the heart (ventricles), can be life-threatening.

Fibrillation – The heart quivers.

  • Atrial Fibrillation – A manageable condition, a common abnormal heart rhythm.
  • Ventricular Fibrillation – A life-threatening condition.

Premature Contraction – early heart beat.

  • Premature Atrial Contractions (PACs) – Occurs in the upper chambers of the heart (atria).
  • Premature Ventricular Contractions (PVCs) – Occurs in the lower chambers of the heart (ventricles).

Symptoms 

Abnormal heart rhythms can cause a wide-range of symptoms. Symptoms may include:

  • Fatigue
  • Dizziness
  • Lightheadedness
  • Fainting
  • Rapid heartbeat
  • Shortness of breath
  • Chest pain
  • Sudden cardiac arrest, in severe cases

Follow Up Care

Lifestyle Changes

  • If you smoke, quit.
  • Limit alcohol and caffeine use.

We offer classes and support groups that focus on the how to care for your heart and vascular system.

Medications

Antiarrhythmic drugs can help correct an irregular or abnormal heartbeat. There are a wide variety of medications available for treatment. Our cardiologists have extensive experience in the use of drug therapy in the treatment of abnormal heart rhythms and can prescribe an appropriate medication. In many cases, abnormal heart rhythms cannot be cured with medication, but can be controlled. Your cardiologist and primary care physician play an important role in the regulation of this medication.

Follow Up Care

MemorialCare's experienced staff provides follow-up care for abnormal heart rhythms. Follow up care may include:

  • Pacemaker and Arrhythmia Clinic

Locations Treating Abnormal Heart Rhythms (Arrhythmias)

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Heart & Vascular Care

MemorialCare Heart and Vascular Institute specializes in minimally invasive heart procedures. With these innovative techniques, patients benefit from fewer complications, less scarring, greater comfort and faster recoveries. Distinguished as a leading heart and vascular institute.

Continuing Education Activity

The sinoatrial node is the natural cardiac pacemaker located in the upper right atrium. The atrioventricular node is a separate cardiac pacemaker located in the inferior-posterior right atrium. The His bundle is a separate cardiac pacemaker located at the inferior end of the atria and ventricle. A junctional rhythm is an abnormal heart rhythm that originates from the AV node or His bundle. This activity reviews the evaluation and management of junctional rhythm and highlights the role of the interprofessional team in educating patients about their prognosis.

Objectives:

  • Outline the risk factors of developing a junctional rhythm.

  • Review the pathophysiology of junctional rhythms.

  • Explain the differential diagnosis of junctional rhythm.

  • Summarize the interprofessional team's strategies for improving care coordination and communication regarding the management of patients with junctional rhythm.

Access free multiple choice questions on this topic.

Introduction

The sinoatrial node (SA) is the default pacemaker and is located subepicardially and is crescent in shape. The atrioventricular node (AV) is a subendocardial structure situated in the inferior-posterior right atrium. It sits within an anatomic region bordered posteriorly by the coronary sinus ostium, superiorly by the tendon of Todaro, and anteriorly by the septal tricuspid valve annulus. This anatomic region is also commonly referred to as the triangle of Koch. The sinoatrial nodal artery supplies blood to the sinoatrial node, it branches off the right coronary artery in 60% of cases, whereas in 40% of cases, it comes from the left circumflex coronary artery. The blood supply to the AV node is from the AV nodal branch of the right coronary artery  (90%) or the left circumflex artery (10%) depending on the right or left dominant blood supply to the heart. The first septal perforator of the left anterior descending artery also supplies blood to the AV node. A junctional rhythm is where the heartbeat originates from the AV node or His bundle, which lies within the tissue at the junction of the atria and the ventricle. Generally, in sinus rhythm, a heartbeat is originated at the SA node. This electrical activity then travels through the atria to the AV node from where it reaches the Bundle of His from where the electrical signals travel to the ventricles through the Purkinje fibers.[1][2][3][4][5][6]

The terminology used to identify the type junctional rhythm depends on its rate and is as follows:

  • Junctional bradycardia: rate below 40 beats per minute 

  • Junction escape rhythm: rate 40 to 60 beats per minute 

  • Accelerated junctional rhythm: rate of 60 to 100 beats per minute

  • Junctional tachycardia: rate above 100 beats per minute

Etiology

When the electrical activity of the SA node is blocked or is less than the automaticity of the AV node/His bundle, a junctional rhythm originates. Numerous conditions and medications can lead to a diseased SA node and lead to the AV node/His bundle taking over due to the higher automaticity of the ectopic pacemaker.[7][8][9]

Some of these conditions and medications are listed below.

  • Chest trauma                                                            

  • Sick sinus syndrome

  • Radiation therapy

  • Collagen vascular disease

  • Myocarditis

  • Clonidine

  • Reserpine

  • Adenosine

  • Cimetidine

  • Antiarrhythmics class I to IV

  • Lithium

  • Amitriptyline

  • Neuromuscular disorder

  • X-linked muscular dystrophy

  • Familial disorder

  • Vasovagal simulation (endotracheal suctioning)

  • Carotid sinus hypersensitivity

  • Beta-blockers

  • Calcium channel blockers

  • Digoxin

  • Ivabradine

  • Opioids

  • Cannabinoids

  • Isoproterenol infusion

  • Hypothyroidism

  • Sleep apnea

  • Hypoxia

  • Intracranial hypertension

  • Hyperkalemia

  • Anorexia nervosa

  • Amyloidosis

  • Pericarditis

  • Lyme disease

  • Rheumatic fever

  • Ischemic heart disease

  • Acute myocardial infarction

  • Acute and chronic coronary artery disease

  • Repair of congenital heart disease

  • Inherited channelopathy

Other than the above-listed causes of severe SA node disease, which can result in junctional rhythm, a high-grade second-degree heart block and a third-degree heart block can also result in a junctional rhythm. Digoxin toxicity can also lead to an accelerated junctional rhythm.

Epidemiology

Junctional rhythm is typical among individuals who have a sinus node dysfunction (SND), and 1 in every 600 cardiac patients above the age of 65 within the United States has SND. Patients with sick sinus syndrome, young children, and athletes who have increased vagal tone may also intermittently exhibit junctional rhythm, especially during sleep. Junctional rhythm is reported equally among males and females.[10]

Pathophysiology

A heart has numerous pacemaker sites within its conduction system, which are independently able to keep the heart beating. And the rate of a heartbeat depends upon the pacemaker site, and as we go down its conduction system, the rate of spontaneous depolarization at pacemaker sites decreases. [1][2][3]

Pacemaker sites and their depolarization rates are listed below:

  • Sinoatrial node: 60 to 100 beats per minute 

  • Atria: less than 60 beats per minute 

  • Atrioventricular node: 40 to 60 beats per minute 

  • Ventricles: 20 to 40 beats per minute

Histopathology

Histopathology of a disease SA node that can contribute to the AV node/His bundle taking over as a pacemaker secondary to their intrinsic automaticity includes SA node fibrosis, atrophy, hypoplasia, or amyloidosis. A normal SA node histopathology does not rule out reduced SA node automaticity contributing to a junctional rhythm.[11][12]

History and Physical

Patients with junctional rhythm may present with a varied array of symptoms or may be asymptomatic. Symptoms mostly depend on the underlying cause of the junctional rhythm, for instance, a patient presenting with heart failure exacerbation may present with shortness of breath, wheezing, and lower extremity edema. Patients with rheumatic fever may present with a heart murmur secondary to the damage to the heart valves, fever, joint pain, and a rash with an electrocardiogram showing a junctional rhythm. Some patients might present with generalized complaints such as dizziness, fatigue, syncope/presyncope, and intermittent palpitations. Non-specific physical exam findings include pulsating veins and regular heart rate with the heart rate varying from 20 to over 100 beats per minute.[13][14][15]

Evaluation

A significant component of an assessment for a patient who presents with signs and symptoms of junctional rhythm is history and physical exam. These should include vital signs (respiratory rate, blood pressure, temperature, and heart rate), a review of the patient's medication list, and an electrocardiogram. See the image below. During their evaluation, it should be established if the patient is hemodynamically stable. The patient should be assessed for any underlying ischemic heart disease or heart failure. A healthcare provider should consider thyroid function testing, pulmonary function testing, including routine blood work, and echocardiography as part of their initial evaluation.[13][14][15]

Treatment / Management

Treatment of a junctional rhythm primarily depends on the underlying cause of the rhythm. In circumstances where the junctional rhythm is a result of underlying sinus node dysfunction that is leading to asystole or bradycardia, it should not be terminated, for it is maintaining the heart rate. Therefore, before establishing a management plan for patients presenting with a junctional rhythm, an underlying etiology must be determined first. Otherwise, healthy individuals who have junctional rhythm and are asymptomatic need no medical management as the rhythm is usually a result of their increased vagal tone suppressing the SA node intrinsic automaticity. In the setting of digoxin toxicity, a patient must be treated with atropine and digoxin-specific antibody. If a patient is refractory to these pharmacologic treatments and goes into junctional tachycardia, intravenous phenytoin can be administered in a monitored setting as these patients can develop hypotension. In the pediatric population, persistent symptomatic junctional tachycardia is an indication for percutaneous radiofrequency ablation. In patients with sick sinus syndrome, or complete or high-grade AV block, a permanent pacemaker is indicated.[16][17][18][19][20]

Differential Diagnosis

  • Digoxin toxicity

  • Atrioventricular nodal reentrant tachycardia

  • Atrioventricular reentrant tachycardia

  • Sinus node dysfunction

  • High-grade second-degree heart block

  • Third-degree heart block

Prognosis

Prognosis is good when the rhythm is promptly identified by a healthcare provider. 

Complications

If not identified promptly symptomatic complications such as syncope, fatigue, or dizziness can occur. 

Deterrence and Patient Education

If available patient education should be provided using resources familiar to the patient including online resources and pamphlets. 

Pearls and Other Issues

Always check serum digoxin levels in patients who are on it for comorbidities. Also, check Lyme titers and empirically treat those patients who present with junctional rhythm and have possible exposure to ticks with antibiotics.

Enhancing Healthcare Team Outcomes

Educating patients at risk for this rhythm and making a closed-loop communication between them and their providers can help further improve the management of these rhythms. An interprofessional team best manages this condition. Initial diagnosis is by primary care or emergency providers. Referral to a cardiologist may be indicated. Cardiology and emergency department nurses administer treatment, monitor responses, and report back to the physician or nurse practitioner. Pharmacists should review prescribed medications, check for drug-drug interactions, and educate patients about dosing and side effects. [Level 5]

Review Questions

You determine a patients heart rate to be 48 beats/min. that heart rate would be categorized as:

Figure

Junctional Rhythm. Contributed by Dhaval Desai, MD, MPH

References

1.

Spodick DH. Normal sinus heart rate: sinus tachycardia and sinus bradycardia redefined. Am Heart J. 1992 Oct;124(4):1119-21. [PubMed: 1529897]

2.

Thery C, Gosselin B, Lekieffre J, Warembourg H. Pathology of sinoatrial node. Correlations with electrocardiographic findings in 111 patients. Am Heart J. 1977 Jun;93(6):735-40. [PubMed: 871100]

3.

Dobrzynski H, Anderson RH, Atkinson A, Borbas Z, D'Souza A, Fraser JF, Inada S, Logantha SJ, Monfredi O, Morris GM, Moorman AF, Nikolaidou T, Schneider H, Szuts V, Temple IP, Yanni J, Boyett MR. Structure, function and clinical relevance of the cardiac conduction system, including the atrioventricular ring and outflow tract tissues. Pharmacol Ther. 2013 Aug;139(2):260-88. [PubMed: 23612425]

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Van der Hauwaert LG, Stroobandt R, Verhaeghe L. Arterial blood supply of the atrioventricular node and main bundle. Br Heart J. 1972 Oct;34(10):1045-51. [PMC free article: PMC458545] [PubMed: 5086972]

5.

Pejković B, Krajnc I, Anderhuber F, Kosutić D. Anatomical aspects of the arterial blood supply to the sinoatrial and atrioventricular nodes of the human heart. J Int Med Res. 2008 Jul-Aug;36(4):691-8. [PubMed: 18652764]

6.

Chua K, Upadhyay GA, Lee E, Aziz Z, Beaser AD, Ozcan C, Broman M, Nayak HM, Tung R. High-resolution mapping of the triangle of Koch: Spatial heterogeneity of fast pathway atrionodal connections. Heart Rhythm. 2018 Mar;15(3):421-429. [PubMed: 29081398]

7.

Semelka M, Gera J, Usman S. Sick sinus syndrome: a review. Am Fam Physician. 2013 May 15;87(10):691-6. [PubMed: 23939447]

8.

Trappe HJ. Tachyarrhythmias, bradyarrhythmias and acute coronary syndromes. J Emerg Trauma Shock. 2010 Apr;3(2):137-42. [PMC free article: PMC2884444] [PubMed: 20606790]

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Silvestri NJ, Ismail H, Zimetbaum P, Raynor EM. Cardiac involvement in the muscular dystrophies. Muscle Nerve. 2018 May;57(5):707-715. [PubMed: 29130502]

10.

Romhilt DW, Doyle M, Sagar KB, Hastillo A, Wolfgang TC, Lower RR, Hess ML. Prevalence and significance of arrhythmias in long-term survivors of cardiac transplantation. Circulation. 1982 Aug;66(2 Pt 2):I219-22. [PubMed: 6177443]

11.

Rodriguez RD, Schocken DD. Update on sick sinus syndrome, a cardiac disorder of aging. Geriatrics. 1990 Jan;45(1):26-30, 33-6. [PubMed: 2403955]

12.

Sanders P, Kistler PM, Morton JB, Spence SJ, Kalman JM. Remodeling of sinus node function in patients with congestive heart failure: reduction in sinus node reserve. Circulation. 2004 Aug 24;110(8):897-903. [PubMed: 15302799]

13.

Kim D, Shinohara T, Joung B, Maruyama M, Choi EK, On YK, Han S, Fishbein MC, Lin SF, Chen PS. Calcium dynamics and the mechanisms of atrioventricular junctional rhythm. J Am Coll Cardiol. 2010 Aug 31;56(10):805-12. [PMC free article: PMC3050609] [PubMed: 20797495]

14.

Cools E, Missant C. Junctional ectopic tachycardia after congenital heart surgery. Acta Anaesthesiol Belg. 2014;65(1):1-8. [PubMed: 24988822]

15.

Di Biase L, Gianni C, Bagliani G, Padeletti L. Arrhythmias Involving the Atrioventricular Junction. Card Electrophysiol Clin. 2017 Sep;9(3):435-452. [PubMed: 28838549]

16.

Tuohy S, Saliba W, Pai M, Tchou P. Catheter ablation as a treatment of atrioventricular block. Heart Rhythm. 2018 Jan;15(1):90-96. [PubMed: 28823599]

17.

Antman EM, Wenger TL, Butler VP, Haber E, Smith TW. Treatment of 150 cases of life-threatening digitalis intoxication with digoxin-specific Fab antibody fragments. Final report of a multicenter study. Circulation. 1990 Jun;81(6):1744-52. [PubMed: 2188752]

18.

Hauptman PJ, Kelly RA. Digitalis. Circulation. 1999 Mar 09;99(9):1265-70. [PubMed: 10069797]

19.

Kelly RA, Smith TW. Recognition and management of digitalis toxicity. Am J Cardiol. 1992 Jun 04;69(18):108G-118G; disc. 118G-119G. [PubMed: 1626485]

20.

Dobrzynski H, Boyett MR, Anderson RH. New insights into pacemaker activity: promoting understanding of sick sinus syndrome. Circulation. 2007 Apr 10;115(14):1921-32. [PubMed: 17420362]

When assessing a patient's pulse you note that it is irregular?

If the pulse is irregular, assess for a pulse deficit, which may indicate an alteration in cardiac output. (For details, see “Assessing Apical-Radial Pulse.”) Report a radial pulse of less than 60 or more than 100 beats per minute, an irregular rhythm, or weak strength to the health care provider without delay.

Which of the following blood pressures represents a patient with moderate hypertension?

Elevated blood pressure. This is sometimes called pre-hypertension. Stage I hypertension (mild): 130-139/80-89 mmHg. Stage II hypertension (moderate): 140/90 mmHg or higher. Stage III hypertension (emergency): 180/120 mmHg or higher with symptoms.

When obtaining a blood pressure the EMT listens for a pulse over which blood vessel?

33. To determine blood pressure, the EMT should position the cuff over the upper arm and place the stethoscope over the brachial artery.

Which pulse site is commonly palpated during the process of obtaining a blood pressure by the palpation technique?

Brachial artery pulse - The brachial artery is palpated on the anterior aspect of the elbow by gently pressing the artery against the underlying bone with the middle and index fingers. The brachial artery pulse is commonly used to measure blood pressure with a stethoscope and sphygmomanometer.