Complete Heart Block Nursing Diagnosis: A Comprehensive Guide

Introduction

Atrioventricular (AV) block occurs when the electrical signals from the atria to the ventricles are delayed or blocked. This disruption in the heart’s electrical conduction system can manifest in varying degrees of severity, impacting cardiac output and overall patient well-being. Understanding the nuances of AV blocks, particularly complete heart block, is crucial for effective diagnosis and management in a nursing context. Normally, the heart’s electrical rhythm is characterized by a P wave preceding each QRS complex, with a consistent PR interval between 120 and 200 milliseconds. This signifies proper AV conduction. However, in AV block, this relationship is disturbed. These blocks are categorized into first, second (Mobitz type 1 and 2), and third-degree blocks, each with distinct electrocardiogram (ECG) characteristics and clinical implications.

While demographic correlations with AV block are not extensively studied, it’s observed across various populations, including athletes and individuals with congenital heart conditions. For nurses, recognizing and responding to these conduction disturbances is paramount, especially in the context of complete heart block, also known as third-degree AV block. This article aims to provide an in-depth understanding of complete heart block, focusing on nursing diagnosis, assessment, and management strategies essential for delivering optimal patient care.

Nursing Diagnoses Related to Heart Block

When caring for patients with heart block, particularly complete heart block, several nursing diagnoses may be pertinent. These diagnoses guide the nursing care plan and address the potential physiological and psychological impacts of this condition. Common nursing diagnoses include:

Ineffective Tissue Perfusion: Due to bradycardia and reduced cardiac output associated with heart block, particularly third-degree block.
Risk for Falls: Secondary to dizziness, syncope, or presyncope resulting from decreased cerebral perfusion.
Impaired Cardiac Function: Related to the underlying electrical conduction disturbance and potential hemodynamic instability.
Anxiety: Associated with the diagnosis of a cardiac condition, potential symptoms, and the need for interventions like pacemaker implantation.

These diagnoses are interconnected and require a holistic nursing approach to manage the patient effectively. Focusing on Complete Heart Block Nursing Diagnosis requires a deep understanding of its specific characteristics and associated nursing care priorities.

Causes of Complete Heart Block

Complete heart block, or third-degree AV block, often indicates a significant underlying pathology affecting the heart’s conduction system. While first and second-degree blocks can sometimes be benign or transient, complete heart block usually signifies a more serious condition.

Pathophysiologic AV Block: Approximately half of complete heart block cases are attributed to chronic idiopathic fibrosis and sclerosis of the conduction system. This degenerative process disrupts the normal electrical pathways within the heart.

Ischemic Heart Disease: A significant contributor, ischemic heart disease is responsible for about 40% of AV block cases. Myocardial infarction, particularly anterior MI, can damage the AV node and conduction pathways, leading to complete heart block.

Cardiomyopathies and Infiltrative Diseases: Conditions such as hypertrophic obstructive cardiomyopathy, sarcoidosis, and amyloidosis can infiltrate the heart muscle and conduction system, impairing electrical transmission.

Infectious and Autoimmune Causes: Infections like Lyme disease, rheumatic fever, endocarditis, and certain viruses can inflame and damage the heart’s electrical system. Similarly, autoimmune diseases such as systemic lupus erythematosus can also contribute to AV block development.

Other Triggers: Cardiac surgery, particularly valve surgeries, can inadvertently damage the conduction system. Certain medications, especially those with AV nodal blocking effects (beta-blockers, calcium channel blockers, digoxin, amiodarone), can induce or exacerbate heart block. Inherited conditions can also predispose individuals to conduction system abnormalities.

Understanding the diverse etiologies of complete heart block is crucial for nurses to anticipate potential risk factors and contribute to accurate diagnosis and patient-specific management strategies.

Risk Factors for Heart Block Progression to Complete Heart Block

While the original article discusses risk factors generally for AV block, when considering complete heart block nursing diagnosis, it’s crucial to understand factors that specifically increase the risk of progression to third-degree block.

Location of the Block: Blocks occurring below the AV node, such as Mobitz type II second-degree block, carry a higher risk of progressing to complete heart block compared to blocks at the AV node level, like Mobitz type I. Infranodal blocks are often due to structural damage and are less stable.

Underlying Cardiac Conditions: Patients with pre-existing heart conditions like ischemic heart disease, cardiomyopathies, or congenital heart defects are at increased risk. These conditions can compromise the conduction system and make it more vulnerable to complete block.

Medications: The use of AV nodal blocking agents, especially in combination or in patients with underlying conduction abnormalities, can precipitate or worsen heart block, potentially leading to complete block.

Electrolyte Imbalances: Hyperkalemia can significantly depress cardiac conduction and increase the risk of AV blocks, including complete heart block.

Acute Myocardial Infarction: Anterior MI, in particular, poses a significant risk for developing Mobitz type II second-degree block and subsequently complete heart block due to damage to the septum and bundle branches.

Age and Degenerative Changes: Age-related degenerative changes in the conduction system increase the susceptibility to conduction disturbances, making older adults more prone to developing complete heart block.

Recognizing these risk factors allows nurses to proactively monitor at-risk patients and promptly identify any signs of AV block progression, especially towards complete heart block.

Assessment of Patients with Suspected Complete Heart Block

A thorough assessment is critical in identifying complete heart block and guiding appropriate nursing interventions. For complete heart block nursing diagnosis, assessment includes:

History Taking:

Cardiac History: Inquire about pre-existing heart conditions, including congenital heart disease, ischemic heart disease, and cardiomyopathies.
Medication Review: Obtain a complete medication list, paying close attention to drugs known to affect AV conduction (beta-blockers, calcium channel blockers, digoxin, antiarrhythmics).
Recent Procedures: Note any recent cardiac procedures, particularly cardiac surgeries or catheter ablations, which could potentially impact the conduction system.
Systemic Diseases: Explore symptoms suggestive of systemic diseases associated with heart block, such as amyloidosis, sarcoidosis, Lyme disease, and autoimmune disorders.
Exercise Capacity: Assess baseline exercise tolerance and any recent changes, as decreased capacity may indicate reduced cardiac output.
Tick Exposure: Inquire about potential tick bites, especially in Lyme-endemic areas.

Symptom Evaluation: Pay close attention to symptoms that may indicate reduced cardiac output and cerebral perfusion due to bradycardia:

Dyspnea: Shortness of breath, especially with exertion or at rest.
Fatigue: Unusual or excessive tiredness and weakness.
Chest Pain: Angina or discomfort in the chest, potentially related to reduced coronary perfusion.
Presyncope or Syncope: Dizziness, lightheadedness, near-fainting or fainting spells, indicating decreased cerebral blood flow.
Sudden Cardiac Arrest: While rare as an initial presentation, it’s a critical consideration in severe cases.

Physical Examination:

Vital Signs: Monitor heart rate (bradycardia is expected in complete heart block), blood pressure (hypotension may be present), and oxygen saturation.
Cardiac Auscultation: Listen for heart sounds, including murmurs or extra heart sounds that may suggest underlying structural heart disease.
Fluid Retention Assessment: Check for signs of heart failure, such as peripheral edema, jugular venous distention, and pulmonary congestion.

12-Lead ECG: The cornerstone of diagnosis. In complete heart block, the ECG will show:

Complete AV Dissociation: P waves and QRS complexes are unrelated, occurring at independent rates.
Regular P-P Intervals: Atrial rate is regular and faster than ventricular rate.
Regular R-R Intervals: Ventricular rate is regular but slower.
Ventricular Escape Rhythm: QRS complexes may be narrow (junctional escape) or wide (ventricular escape), depending on the location of the block and the origin of the escape rhythm.

Prompt and accurate assessment, particularly ECG interpretation, is vital for nurses to recognize complete heart block and initiate timely interventions.

Evaluation and Types of Heart Block: Focusing on Complete Heart Block

The original article provides a good overview of all degrees of AV block. However, for complete heart block nursing diagnosis, a deeper dive into third-degree block is essential.

First-Degree AV Block: Characterized by a prolonged PR interval (>200ms) but with every P wave followed by a QRS complex. It’s generally benign and often requires no specific treatment.

Second-Degree AV Block:

Mobitz Type 1 (Wenckebach): Progressive PR interval prolongation until a QRS complex is dropped. Usually occurs at the AV node and is often benign.
Mobitz Type 2: Sudden, intermittent dropped QRS complexes without progressive PR prolongation. Indicates a more serious infranodal block and higher risk of progression to complete heart block.

Third-Degree (Complete) AV Block: This is the most severe form. There is no conduction of atrial impulses to the ventricles. The atria and ventricles beat independently.

ECG Characteristics of Complete Heart Block: As described in the assessment section, the hallmark is AV dissociation. The ventricular rate is slow, typically 20-40 bpm if a ventricular escape rhythm is present, or 40-60 bpm if a junctional escape rhythm takes over.
Clinical Significance of Complete Heart Block: Complete heart block is hemodynamically significant. The slow ventricular rate can lead to reduced cardiac output, causing symptoms like fatigue, dizziness, syncope, and even cardiac arrest. It requires prompt recognition and intervention, usually with a pacemaker.

Figure 5. ECG demonstrating third-degree atrioventricular block with independent atrial and ventricular rhythms, indicating complete conduction failure.

Differentiating complete heart block from other AV blocks is crucial for appropriate management. Recognizing the ECG patterns and understanding the clinical implications are essential skills for nurses.

Medical Management of Complete Heart Block

Medical management of complete heart block is focused on restoring adequate heart rate and cardiac output.

Immediate Management:

Cardiac Monitoring: Continuous ECG monitoring is essential to observe the heart rhythm and detect any changes.
Oxygen Therapy: Administer oxygen to improve oxygenation, especially if the patient is symptomatic or hypoxic.
Temporary Pacing: In symptomatic patients or those with hemodynamic instability, temporary pacing is often necessary. This can be achieved via transcutaneous pacing (external pacing pads) or transvenous pacing (insertion of a pacing wire through a vein into the right ventricle). Temporary pacing provides immediate rate support until a more definitive solution is implemented.
Medications (Limited Role): While atropine may be used for Mobitz type 1 block, it is generally ineffective and potentially harmful in Mobitz type 2 and complete heart block, especially if the block is infranodal. Isoproterenol, a beta-adrenergic agonist, can increase heart rate but is less commonly used due to potential side effects and the preference for pacing.

Permanent Pacemaker Implantation: The definitive treatment for chronic complete heart block is usually permanent pacemaker implantation.

Indications for Permanent Pacing: Symptomatic complete heart block, asymptomatic complete heart block with slow ventricular escape rhythm, or complete heart block due to reversible causes that are unlikely to resolve quickly.
Pacemaker Types: Dual-chamber pacemakers (pacing both atrium and ventricle) are often preferred to maintain AV synchrony, but single-chamber ventricular pacemakers may be used in certain situations.
Post-Pacemaker Implantation Care: Nursing care post-pacemaker implantation is crucial, including monitoring the incision site for infection, assessing for complications like pneumothorax or lead displacement, and patient education regarding pacemaker care and follow-up.

Nurses play a vital role in monitoring patients, implementing temporary pacing if needed, and providing pre- and post-operative care for permanent pacemaker implantation.

Nursing Management of Patients with Complete Heart Block

Nursing management is integral to the care of patients with complete heart block. For effective complete heart block nursing diagnosis and care, consider the following:

Monitoring and Assessment:

Continuous Vital Sign Monitoring: Closely monitor heart rate, blood pressure, respiratory rate, and oxygen saturation.
ECG Monitoring: Continuously monitor the ECG for rhythm changes, pacemaker function (if applicable), and signs of ischemia.
Neurological Assessment: Regularly assess neurological status, including level of consciousness, orientation, and presence of dizziness or syncope.
Fluid Balance Monitoring: Assess for signs of fluid overload or dehydration, especially if heart failure is present.
Electrolyte Monitoring: Monitor serum electrolyte levels, particularly potassium, magnesium, and calcium, as imbalances can affect cardiac rhythm.

Nursing Interventions:

Ensure Bed Rest: Maintain bed rest, especially during symptomatic episodes, to reduce myocardial workload and prevent falls.
Oxygen Administration: Administer supplemental oxygen as needed to maintain adequate oxygen saturation.
Medication Management: Hold medications that can exacerbate bradycardia or AV block, as ordered by the physician.
Prepare for Temporary Pacing: If temporary pacing is indicated, prepare the patient physically and psychologically for the procedure. Ensure availability of pacing equipment and trained personnel.
Pacemaker Education: For patients undergoing permanent pacemaker implantation, provide comprehensive education pre- and post-procedure. This includes explaining the procedure, device function, incision care, activity restrictions, signs of complications, and follow-up appointments.
Fall Prevention: Implement fall precautions due to the risk of dizziness and syncope. This includes assisting with ambulation, ensuring a safe environment, and educating the patient about fall risks.
Anxiety Management: Address patient anxiety and fear related to their cardiac condition and procedures. Provide emotional support, clear explanations, and involve family members as appropriate.

Post-Pacemaker Implantation Nursing Care:

Incision Site Care: Monitor the pacemaker insertion site for signs of infection (redness, swelling, drainage). Provide wound care as prescribed.
Arm Immobilization: Instruct the patient to limit arm movement on the pacemaker insertion side for a period post-implantation to prevent lead dislodgement.
Pain Management: Manage post-operative pain with analgesics as prescribed.
Pacemaker Function Check: Ensure pacemaker function is checked post-implantation and at follow-up appointments.
Education on Pacemaker Precautions: Educate patients about avoiding strong magnetic fields (MRI, some security systems), informing healthcare providers and TSA about their pacemaker, and carrying a pacemaker identification card.
Activity Guidelines: Provide guidelines on gradual resumption of activity, avoiding strenuous upper body activities initially.
Medical Alert Bracelet: Advise patients to wear a medical alert bracelet indicating they have a pacemaker.

Effective nursing management is crucial for optimizing outcomes and ensuring patient safety and well-being in individuals with complete heart block.

When to Seek Immediate Medical Help for Heart Block Symptoms

It is crucial to educate patients and caregivers about when to seek immediate medical attention. Symptoms that warrant urgent medical evaluation include:

Loss of Consciousness (Syncope): Fainting or passing out.
Altered Mental Status: Confusion, disorientation, or unusual drowsiness.
Persistent Dizziness or Lightheadedness (Presyncope): Especially if accompanied by other symptoms.
Severe Shortness of Breath: Difficulty breathing or gasping for air.
Chest Pain: Angina or discomfort in the chest.
Unexplained Fatigue: Sudden onset of severe fatigue.
Slow Heart Rate (Bradycardia): Especially if accompanied by any of the above symptoms.

These symptoms may indicate hemodynamic compromise due to complete heart block and require immediate medical intervention.

Outcome Identification and Prognosis

The prognosis for patients with complete heart block depends on several factors:

Underlying Cause: Reversible causes (medication-induced, Lyme disease) may have a better prognosis if addressed promptly. Irreversible causes (degenerative conduction system disease, structural heart disease) often require permanent pacing.
Age and Comorbidities: Older patients and those with other chronic medical conditions (diabetes, kidney disease, underlying heart disease) may have a less favorable prognosis.
Ventricular Escape Rhythm Rate: Patients with very slow ventricular escape rhythms or unstable escape rhythms have a higher risk of complications.
Promptness of Treatment: Timely diagnosis and treatment, especially pacemaker implantation when indicated, significantly improve outcomes.

With permanent pacemaker therapy, most patients with chronic complete heart block can live relatively normal lives. Without treatment, complete heart block carries a significant risk of sudden cardiac death.

Coordination of Care for Complete Heart Block

Effective management of complete heart block requires a multidisciplinary approach.

Interprofessional Team: Collaboration between cardiologists, electrophysiologists, nurses, and primary care physicians is essential.
Cardiologist Referral: Patients with complete heart block should be promptly referred to a cardiologist or electrophysiologist for definitive diagnosis and management, including consideration for pacemaker implantation.
Cardiology Nurse Follow-up: Cardiology nurses play a crucial role in post-pacemaker implantation follow-up, monitoring heart rate, rhythm, pacemaker function, and patient symptoms. They provide ongoing education and support.
Surgical Considerations: When patients with pacemakers require surgery, coordination with the cardiologist is necessary to manage pacemaker settings and minimize potential interference during the procedure.

Effective coordination of care ensures comprehensive and patient-centered management of complete heart block.

Health Teaching and Health Promotion

Patient education is a cornerstone of long-term management. For complete heart block, health teaching should include:

Understanding Heart Block: Explain complete heart block in simple terms, emphasizing the electrical conduction problem and the role of the pacemaker if implanted.
Pacemaker Care: Provide detailed instructions on incision care, activity restrictions, pacemaker precautions (magnetic fields), and recognizing signs of pacemaker malfunction or infection.
Medication Adherence: Reinforce the importance of taking prescribed medications and avoiding medications that can worsen bradycardia without consulting their physician.
Symptom Recognition: Educate patients about alarming symptoms of hypoperfusion (fatigue, lightheadedness, syncope, angina) and the need to seek prompt medical attention if these occur.
Regular Follow-up: Emphasize the importance of regular follow-up appointments with their cardiologist or pacemaker clinic for device checks and overall cardiac care.
Medical Alert Bracelet: Advise wearing a medical alert bracelet indicating the presence of a pacemaker and their cardiac condition.

Health promotion focuses on empowering patients to actively participate in their care, recognize warning signs, and maintain optimal health with complete heart block.

Conclusion

Complete heart block is a serious cardiac conduction disorder requiring prompt recognition and management. Nurses are central to the care of these patients, from initial assessment and ECG interpretation to post-pacemaker implantation care and patient education. Understanding complete heart block nursing diagnosis, associated symptoms, medical and nursing management strategies, and essential patient education points is crucial for providing high-quality, patient-centered care and improving outcomes for individuals with this condition. By focusing on comprehensive assessment, vigilant monitoring, and thorough patient education, nurses can significantly impact the well-being of patients with complete heart block.

References

1.Żuchowski B, Błaszyk K, Piskorski J, Wykrętowicz A, Guzik P. Dependence of the Atrioventricular Conduction Time on the Conduction through the Atrioventricular Node and His-Purkinje System. J Clin Med. 2023 Feb 07;12(4) [PMC free article: PMC9958776] [PubMed: 36835864]

2.Wu J, Zipes DP. Mechanisms underlying atrioventricular nodal conduction and the reentrant circuit of atrioventricular nodal reentrant tachycardia using optical mapping. J Cardiovasc Electrophysiol. 2002 Aug;13(8):831-4. [PubMed: 12212708]

3.Prystowsky EN, Jackman WM, Rinkenberger RL, Heger JJ, Zipes DP. Effect of autonomic blockade on ventricular refractoriness and atrioventricular nodal conduction in humans. Evidence supporting a direct cholinergic action on ventricular muscle refractoriness. Circ Res. 1981 Aug;49(2):511-8. [PubMed: 7249285]

4.Kwok CS, Rashid M, Beynon R, Barker D, Patwala A, Morley-Davies A, Satchithananda D, Nolan J, Myint PK, Buchan I, Loke YK, Mamas MA. Prolonged PR interval, first-degree heart block and adverse cardiovascular outcomes: a systematic review and meta-analysis. Heart. 2016 May;102(9):672-80. [PubMed: 26879241]

5.Epstein AE, DiMarco JP, Ellenbogen KA, Estes NA, Freedman RA, Gettes LS, Gillinov AM, Gregoratos G, Hammill SC, Hayes DL, Hlatky MA, Newby LK, Page RL, Schoenfeld MH, Silka MJ, Stevenson LW, Sweeney MO, Smith SC, Jacobs AK, Adams CD, Anderson JL, Buller CE, Creager MA, Ettinger SM, Faxon DP, Halperin JL, Hiratzka LF, Hunt SA, Krumholz HM, Kushner FG, Lytle BW, Nishimura RA, Ornato JP, Page RL, Riegel B, Tarkington LG, Yancy CW., American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the ACC/AHA/NASPE 2002 Guideline Update for Implantation of Cardiac Pacemakers and Antiarrhythmia Devices). American Association for Thoracic Surgery. Society of Thoracic Surgeons. ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the ACC/AHA/NASPE 2002 Guideline Update for Implantation of Cardiac Pacemakers and Antiarrhythmia Devices) developed in collaboration with the American Association for Thoracic Surgery and Society of Thoracic Surgeons. J Am Coll Cardiol. 2008 May 27;51(21):e1-62. [PubMed: 18498951]

6.Sheldon RS, Lei LY, Solbiati M, Chew DS, Raj SR, Costantino G, Morillo C, Sandhu RK. Electrophysiology studies for predicting atrioventricular block in patients with syncope: A systematic review and meta-analysis. Heart Rhythm. 2021 Aug;18(8):1310-1317. [PubMed: 33887450]

7.Dhingra RC, Amat-y-Leon F, Pouget JM, Rosen KM. Infranodal block: diagnosis, clinical significance, and management. Med Clin North Am. 1976 Jan;60(1):175-92. [PubMed: 1107691]

8.Warnes CA. Transposition of the great arteries. Circulation. 2006 Dec 12;114(24):2699-709. [PubMed: 17159076]

9.Karpawich PP, Gillette PC, Garson A, Hesslein PS, Porter CB, McNamara DG. Congenital complete atrioventricular block: clinical and electrophysiologic predictors of need for pacemaker insertion. Am J Cardiol. 1981 Dec;48(6):1098-102. [PubMed: 7304459]

10.Ambrosi A, Wahren-Herlenius M. Congenital heart block: evidence for a pathogenic role of maternal autoantibodies. Arthritis Res Ther. 2012 Apr 26;14(2):208. [PMC free article: PMC3446439] [PubMed: 22546326]

11.Buyon JP, Hiebert R, Copel J, Craft J, Friedman D, Katholi M, Lee LA, Provost TT, Reichlin M, Rider L, Rupel A, Saleeb S, Weston WL, Skovron ML. Autoimmune-associated congenital heart block: demographics, mortality, morbidity and recurrence rates obtained from a national neonatal lupus registry. J Am Coll Cardiol. 1998 Jun;31(7):1658-66. [PubMed: 9626848]

12.Ye Z, Wang L, Yang T, Chen L, Wang T, Chen L, Zhao L, Zhang S, Zheng Z, Luo L, Qin J. Maternal Viral Infection and Risk of Fetal Congenital Heart Diseases: A Meta-Analysis of Observational Studies. J Am Heart Assoc. 2019 May 07;8(9):e011264. [PMC free article: PMC6512143] [PubMed: 30995883]

13.Barra SN, Providência R, Paiva L, Nascimento J, Marques AL. A review on advanced atrioventricular block in young or middle-aged adults. Pacing Clin Electrophysiol. 2012 Nov;35(11):1395-405. [PubMed: 22897386]

14.LENEGRE J. ETIOLOGY AND PATHOLOGY OF BILATERAL BUNDLE BRANCH BLOCK IN RELATION TO COMPLETE HEART BLOCK. Prog Cardiovasc Dis. 1964 Mar;6:409-44. [PubMed: 14153648]

15.LEV M. ANATOMIC BASIS FOR ATRIOVENTRICULAR BLOCK. Am J Med. 1964 Nov;37:742-8. [PubMed: 14237429]

16.Alboni P, Holz A, Brignole M. Vagally mediated atrioventricular block: pathophysiology and diagnosis. Heart. 2013 Jul;99(13):904-8. [PubMed: 23286970]

17.Kottkamp H. Fibrotic atrial cardiomyopathy: a specific disease/syndrome supplying substrates for atrial fibrillation, atrial tachycardia, sinus node disease, AV node disease, and thromboembolic complications. J Cardiovasc Electrophysiol. 2012 Jul;23(7):797-9. [PubMed: 22554187]

18.Rajdev A, Groh WJ. Arrhythmias in the muscular dystrophies. Card Electrophysiol Clin. 2015 Jun;7(2):303-8. [PMC free article: PMC4441951] [PubMed: 26002394]

19.Ferrari AD, Süssenbach CP, Guaragna JC, Piccoli Jda C, Gazzoni GF, Ferreira DK, Albuquerque LC, Goldani MA. Atrioventricular block in the postoperative period of heart valve surgery: incidence, risk factors and hospital evolution. Rev Bras Cir Cardiovasc. 2011 Jul-Sep;26(3):364-72. [PubMed: 22086572]

20.Siontis GC, Jüni P, Pilgrim T, Stortecky S, Büllesfeld L, Meier B, Wenaweser P, Windecker S. Predictors of permanent pacemaker implantation in patients with severe aortic stenosis undergoing TAVR: a meta-analysis. J Am Coll Cardiol. 2014 Jul 15;64(2):129-40. [PubMed: 25011716]

21.Chandler SF, Fynn-Thompson F, Mah DY. Role of cardiac pacing in congenital complete heart block. Expert Rev Cardiovasc Ther. 2017 Nov;15(11):853-861. [PubMed: 28875729]

22.Upshaw CB. Comparison of the prevalence of first-degree atrioventricular block in African-American and in Caucasian patients: an electrocardiographic study III. J Natl Med Assoc. 2004 Jun;96(6):756-60. [PMC free article: PMC2568382] [PubMed: 15233485]

23.Moak JP, Barron KS, Hougen TJ, Wiles HB, Balaji S, Sreeram N, Cohen MH, Nordenberg A, Van Hare GF, Friedman RA, Perez M, Cecchin F, Schneider DS, Nehgme RA, Buyon JP. Congenital heart block: development of late-onset cardiomyopathy, a previously underappreciated sequela. J Am Coll Cardiol. 2001 Jan;37(1):238-42. [PubMed: 11153745]

24.Bourke JP. Atrioventricular block and problems with atrioventricular conduction. Clin Geriatr Med. 2002 May;18(2):229-51. [PubMed: 12180245]

25.Abu Rmilah AA, Al-Zu’bi H, Haq IU, Yagmour AH, Jaber SA, Alkurashi AK, Qaisi I, Kowlgi GN, Cha YM, Mulpuru S, DeSimone CV, Deshmukh AJ. Predicting permanent pacemaker implantation following transcatheter aortic valve replacement: A contemporary meta-analysis of 981,168 patients. Heart Rhythm O2. 2022 Aug;3(4):385-392. [PMC free article: PMC9463692] [PubMed: 36097458]

26.Writing Committee Members. Kusumoto FM, Schoenfeld MH, Barrett C, Edgerton JR, Ellenbogen KA, Gold MR, Goldschlager NF, Hamilton RM, Joglar JA, Kim RJ, Lee R, Marine JE, McLeod CJ, Oken KR, Patton KK, Pellegrini CN, Selzman KA, Thompson A, Varosy PD. 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Heart Rhythm. 2019 Sep;16(9):e128-e226. [PubMed: 30412778]

27.Zeltser D, Justo D, Halkin A, Rosso R, Ish-Shalom M, Hochenberg M, Viskin S. Drug-induced atrioventricular block: prognosis after discontinuation of the culprit drug. J Am Coll Cardiol. 2004 Jul 07;44(1):105-8. [PubMed: 15234417]

28.Glikson M, Nielsen JC, Kronborg MB, Michowitz Y, Auricchio A, Barbash IM, Barrabés JA, Boriani G, Braunschweig F, Brignole M, Burri H, Coats AJS, Deharo JC, Delgado V, Diller GP, Israel CW, Keren A, Knops RE, Kotecha D, Leclercq C, Merkely B, Starck C, Thylén I, Tolosana JM. Corrigendum to: 2021 ESC Guidelines on cardiac pacing and cardiac resynchronization therapy: Developed by the Task Force on cardiac pacing and cardiac resynchronization therapy of the European Society of Cardiology (ESC): With the special contribution of the European Heart Rhythm Association (EHRA). Europace. 2022 Apr 05;24(4):699. [PubMed: 35253863]

29.Knabben V, Chhabra L, Slane M. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Jul 31, 2023. Third-Degree Atrioventricular Block. [PubMed: 31424783]

30.STACK MF, RADER B, SOBOL BJ, FARBER SJ, EICHNA LW. Cardiovascular hemodynamic functions in complete heart block and the effect of isopropylnorepinephrine. Circulation. 1958 Apr;17(4, Part 1):526-36. [PubMed: 13523763]

31.Morin DP, Bernard ML. Extreme “cannon A waves” and pulsatile skin color in complete heart block. HeartRhythm Case Rep. 2017 Oct;3(10):493. [PMC free article: PMC5643861] [PubMed: 29062706]

32.Oldroyd SH, Quintanilla Rodriguez BS, Makaryus AN. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Jan 19, 2023. First-Degree Heart Block. [PMC free article: PMC448164] [PubMed: 28846254]

33.Lewalter T, Pürerfellner H, Ungar A, Rieger G, Mangoni L, Duru F., INSIGHT XT study investigators. “First-degree AV block-a benign entity?” Insertable cardiac monitor in patients with 1st-degree AV block reveals presence or progression to higher grade block or bradycardia requiring pacemaker implant. J Interv Card Electrophysiol. 2018 Aug;52(3):303-306. [PubMed: 30105427]

34.Burri H, Zimmermann M. Infranodal Wenckebach conduction block and illustration of the gap phenomenon. HeartRhythm Case Rep. 2021 Feb;7(2):63-64. [PMC free article: PMC7897724] [PubMed: 33665102]

35.Surawicz B, Childers R, Deal BJ, Gettes LS, Bailey JJ, Gorgels A, Hancock EW, Josephson M, Kligfield P, Kors JA, Macfarlane P, Mason JW, Mirvis DM, Okin P, Pahlm O, Rautaharju PM, van Herpen G, Wagner GS, Wellens H., American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology. American College of Cardiology Foundation. Heart Rhythm Society. AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part III: intraventricular conduction disturbances: a scientific statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. Endorsed by the International Society for Computerized Electrocardiology. J Am Coll Cardiol. 2009 Mar 17;53(11):976-81. [PubMed: 19281930]

36.Barold SS. 2:1 Atrioventricular block: order from chaos. Am J Emerg Med. 2001 May;19(3):214-7. [PubMed: 11326349]

37.Linzer M, Yang EH, Estes NA, Wang P, Vorperian VR, Kapoor WN. Diagnosing syncope. Part 1: Value of history, physical examination, and electrocardiography. Clinical Efficacy Assessment Project of the American College of Physicians. Ann Intern Med. 1997 Jun 15;126(12):989-96. [PubMed: 9182479]

38.Linzer M, Yang EH, Estes NA, Wang P, Vorperian VR, Kapoor WN. Diagnosing syncope. Part 2: Unexplained syncope. Clinical Efficacy Assessment Project of the American College of Physicians. Ann Intern Med. 1997 Jul 01;127(1):76-86. [PubMed: 9214258]

39.Coplan NL, Morales MC, Romanello P, Wilentz JR, Moses JW. Exercise-related atrioventricular block. Influence of myocardial ischemia. Chest. 1991 Dec;100(6):1728-30. [PubMed: 1959424]

40.Fontana M, Pica S, Reant P, Abdel-Gadir A, Treibel TA, Banypersad SM, Maestrini V, Barcella W, Rosmini S, Bulluck H, Sayed RH, Patel K, Mamhood S, Bucciarelli-Ducci C, Whelan CJ, Herrey AS, Lachmann HJ, Wechalekar AD, Manisty CH, Schelbert EB, Kellman P, Gillmore JD, Hawkins PN, Moon JC. Prognostic Value of Late Gadolinium Enhancement Cardiovascular Magnetic Resonance in Cardiac Amyloidosis. Circulation. 2015 Oct 20;132(16):1570-9. [PMC free article: PMC4606985] [PubMed: 26362631]

41.Fisher JD. Role of electrophysiologic testing in the diagnosis and treatment of patients with known and suspected bradycardias and tachycardias. Prog Cardiovasc Dis. 1981 Jul-Aug;24(1):25-90. [PubMed: 7019962]

42.Podoleanu C, DaCosta A, Defaye P, Taieb J, Galley D, Bru P, Maury P, Mabo P, Boveda S, Cellarier G, Anselme F, Kouakam C, Delarche N, Deharo JC., FRESH investigators. Early use of an implantable loop recorder in syncope evaluation: a randomized study in the context of the French healthcare system (FRESH study). Arch Cardiovasc Dis. 2014 Oct;107(10):546-52. [PubMed: 25241220]

43.Ackerman MJ, Priori SG, Willems S, Berul C, Brugada R, Calkins H, Camm AJ, Ellinor PT, Gollob M, Hamilton R, Hershberger RE, Judge DP, Le Marec H, McKenna WJ, Schulze-Bahr E, Semsarian C, Towbin JA, Watkins H, Wilde A, Wolpert C, Zipes DP. HRS/EHRA expert consensus statement on the state of genetic testing for the channelopathies and cardiomyopathies this document was developed as a partnership between the Heart Rhythm Society (HRS) and the European Heart Rhythm Association (EHRA). Heart Rhythm. 2011 Aug;8(8):1308-39. [PubMed: 21787999]

44.Glikson M, Nielsen JC, Kronborg MB, Michowitz Y, Auricchio A, Barbash IM, Barrabés JA, Boriani G, Braunschweig F, Brignole M, Burri H, Coats AJS, Deharo JC, Delgado V, Diller GP, Israel CW, Keren A, Knops RE, Kotecha D, Leclercq C, Merkely B, Starck C, Thylén I, Tolosana JM., ESC Scientific Document Group. [2021 ESC Guidelines on cardiac pacing and cardiac resynchronization therapy Developed by the Task Force on cardiac pacing and cardiac resynchronization therapy of the European Society of Cardiology (ESC) With the special contribution of the European Heart Rhythm Association (EHRA)]. G Ital Cardiol (Rome). 2022 Jul;23(7 Suppl 1):e1-e94. [PubMed: 35771031]

45.Brady WJ, Swart G, DeBehnke DJ, Ma OJ, Aufderheide TP. The efficacy of atropine in the treatment of hemodynamically unstable bradycardia and atrioventricular block: prehospital and emergency department considerations. Resuscitation. 1999 Jun;41(1):47-55. [PubMed: 10459592]

46.Hickey AR, Wenger TL, Carpenter VP, Tilson HH, Hlatky MA, Furberg CD, Kirkpatrick CH, Strauss HC, Smith TW. Digoxin Immune Fab therapy in the management of digitalis intoxication: safety and efficacy results of an observational surveillance study. J Am Coll Cardiol. 1991 Mar 01;17(3):590-8. [PubMed: 1993775]

47.Kennebäck G, Tabrizi F, Lindell P, Nordlander R. High-degree atrioventricular block during anti-arrhythmic drug treatment: use of a pacemaker with a bradycardia-detection algorithm to study the time course after drug withdrawal. Europace. 2007 Mar;9(3):186-91. [PubMed: 17255148]

48.Bjørnstad CC, Gjertsen E, Thorup F, Gundersen T, Tobiasson K, Otterstad JE. Temporary cardiac pacemaker treatment in five Norwegian regional hospitals. Scand Cardiovasc J. 2012 Jun;46(3):137-43. [PubMed: 22390277]

49.Strasberg B, Amat-Y-Leon F, Dhingra RC, Palileo E, Swiryn S, Bauernfeind R, Wyndham C, Rosen KM. Natural history of chronic second-degree atrioventricular nodal block. Circulation. 1981 May;63(5):1043-9. [PubMed: 7471363]

50.Barold SS. Indications for permanent cardiac pacing in first-degree AV block: class I, II, or III? Pacing Clin Electrophysiol. 1996 May;19(5):747-51. [PubMed: 8734740]

51.Simon AB, Zloto AE. Atrioventricular block: natural history after permanent ventricular pacing. Am J Cardiol. 1978 Mar;41(3):500-7. [PubMed: 626128]

52.Bhakta D, Shen C, Kron J, Epstein AE, Pascuzzi RM, Groh WJ. Pacemaker and implantable cardioverter-defibrillator use in a US myotonic dystrophy type 1 population. J Cardiovasc Electrophysiol. 2011 Dec;22(12):1369-75. [PubMed: 22035077]

53.Connolly SJ, Kerr CR, Gent M, Roberts RS, Yusuf S, Gillis AM, Sami MH, Talajic M, Tang AS, Klein GJ, Lau C, Newman DM. Effects of physiologic pacing versus ventricular pacing on the risk of stroke and death due to cardiovascular causes. Canadian Trial of Physiologic Pacing Investigators. N Engl J Med. 2000 May 11;342(19):1385-91. [PubMed: 10805823]

54.Sweeney MO, Hellkamp AS, Ellenbogen KA, Greenspon AJ, Freedman RA, Lee KL, Lamas GA., MOde Selection Trial Investigators. Adverse effect of ventricular pacing on heart failure and atrial fibrillation among patients with normal baseline QRS duration in a clinical trial of pacemaker therapy for sinus node dysfunction. Circulation. 2003 Jun 17;107(23):2932-7. [PubMed: 12782566]

55.SANGHVI LM. Isorhythmic dissociation. Am J Cardiol. 1961 Aug;8:293-6. [PubMed: 13746248]

56.Edhag O, Swahn A. Prognosis of patients with complete heart block or arrhythmic syncope who were not treated with artificial pacemakers. A long-term follow-up study of 101 patients. Acta Med Scand. 1976;200(6):457-63. [PubMed: 1015354]

57.Johansson BW. Complete heart block. A clinical, hemodynamic and pharmacological study in patients with and without an artificial pacemaker. Acta Med Scand Suppl. 1966;451:1-127. [PubMed: 5223645]

58.Lopez-Jimenez F, Goldman L, Orav EJ, Ellenbogen K, Stambler B, Marinchak R, Wilkoff BL, Mangione CM, Yoon C, Vitale K, Lamas GA. Health values before and after pacemaker implantation. Am Heart J. 2002 Oct;144(4):687-92. [PubMed: 12360166]

59.Edhag O. Long-term cardiac pacing. Experience of fixed-rate pacing with an endocardial electrode in 260 patients. Acta Med Scand Suppl. 1969;502:9-110. [PubMed: 5265649]

60.Jeon JH, Her SH, Chin JY, Park KH, Yoon HJ, Lee JM, Jin SW. Complete atrioventricular block-induced Torsade de pointes, manifested by epilepsy. Korean J Intern Med. 2011 Mar;26(1):99-102. [PMC free article: PMC3056264] [PubMed: 21437170]

61.Irwin ME. Cardiac pacing device therapy for atrial dysrhythmias: how does it work? AACN Clin Issues. 2004 Jul-Sep;15(3):377-90. [PubMed: 15475812]