Third-Degree Atrioventricular Block


Article Author:
Vinicius Knabben
Lovely Chhabra


Article Editor:
Matthew Slane


Editors In Chief:
Dustin Constant
Donald Kushner


Managing Editors:
Avais Raja
Orawan Chaigasame
Carrie Smith
Abdul Waheed
Khalid Alsayouri
Trevor Nezwek
Radia Jamil
Erin Hughes
Patrick Le
Anoosh Zafar Gondal
Saad Nazir
William Gossman
Hassam Zulfiqar
Hussain Sajjad
Steve Bhimji
Muhammad Hashmi
John Shell
Matthew Varacallo
Heba Mahdy
Ahmad Malik
Sarosh Vaqar
Mark Pellegrini
James Hughes
Beata Beatty
Beenish Sohail
Nazia Sadiq
Hajira Basit
Phillip Hynes


Updated:
8/11/2019 6:16:17 PM

Introduction

An atrioventricular block is a loss of the regular function of the cardiac electroconductive pathways linking the sinoatrial node (SA node) and the ventricles via conduction through the atrioventricular node (AV node). Third-degree AV block indicates a complete loss of communication between the atria and the ventricles. Without appropriate conduction through the AV node, the SA node cannot act to control the heart rate, and cardiac output can diminish secondary to loss of coordination of the atria and the ventricles. The condition can be fatal if not promptly treated. Most patients will initially require temporary pacing, followed by a permanent pacemaker.

Etiology

The underlying cause of AV blocks is varied and the same for all degrees of blocks. These causes include idiopathic fibrosis and underlying chronic cardiac diseases such as structural heart disease, acute ischemic heart disease, medication toxicity, nodal ablation, electrolyte abnormalities, and post-operative heart block such as after surgical or transcatheter aortic valve replacement.[1] Additional causes of AV block include Lyme disease and some systemic diseases such as collagen vascular disorders, amyloidosis, sarcoidosis, and lupus.

Drugs associated with third-degree heart block include:

  • Anti-arrhythmics from all four classes
  • Digoxin

An anterior wall MI with an infranodal complete heart block is a life-threatening condition. About 5 to 10% of patients with an inferior wall, MI will develop complete heart block, but this may resolve within 2 to 48 hours. In general, a complete heart block after an acute MI is rare.  AV blocks may accompany right coronary artery occlusion and most resolve after revascularization.

AV block can occur after open-heart surgery, septal alcohol infusion, and percutaneous coronary interventions. After aortic valve surgery, complete heart block is more likely in female patients and the presence of annular calcification.

Epidemiology

Although AV blocks are fairly common, third-degree AV block is relatively rare.[2] The incidence in the general population appears to be low, approximately 0.02% to 0.04%.[3]  Given the etiology of the disease, the incidence among the apparently healthy and presumptively asymptomatic is even lower at approximately 0.001%.[4] Similarly, as one looks at people with a greater disease burden, the incidence increases with a study of patients in the Veterans Health Administration demonstrating an incidence at of 1.1% in those with diabetes mellitus and 0.6% in those with hypertension.[5]

Pathophysiology

Under its regular function, the AV node receives an impulse from the SA node. That impulse gets delayed in the AV node, assuring the contraction cycle in the atria is complete before a contraction begins in the ventricles. From the AV node, the electrical impulse passes through the His-Purkinje system to activate ventricular contraction. When there is a pathological delay in the AV node, it is visualized on an electrocardiogram as a change in the P-R interval. These delays are known as an AV block. These delays fall into categories of first, second, and third-degree blocks. Third-degree blocks are also known as complete heart block. As the name implies, no impulses from the SA node get conducted to the ventricles, and this leads to a complete atrioventricular dissociation. The SA node continues to activate at a set rhythm, but the ventricles will activate through an escape rhythm that can be mediated by either the AV node (junctional escape), one of the fascicles (fascicular escape), or by ventricular myocytes themselves (ventricular escape rhythm).[1]

The heart rate will typically be less than 45 to 50 beats/min, and most patients will be hemodynamically unstable. This rhythm is unresponsive to atropine and exercise.

History and Physical

Patients with third-degree blocks can have varying clinical presentations. Rarely, patients are asymptomatic. Usually, they may present with generalized fatigue, tiredness, chest pain, shortness of breath, presyncope, or syncope. They may have a significant hemodynamic instability and can be obtunded. The patient's status at the time of presentation can vary depending upon the concurrent disease and the rate of the escape rhythm. Patients with complete AV-block accompanying an acute myocardial infarction often have ischemic symptoms of chest pain or dyspnea. The past medical history will often include the presence of cardiovascular disease and/or its risk factors, including diabetes mellitus, hypertension, dyslipidemia, and smoking, etc. The physical exam is usually remarkable for bradycardia. JVP exam often demonstrates cannon A-waves as the atria and ventricles contract simultaneously, which results in significant pushing of the blood against the AV valve. Thus a very large pressure wave runs up against the vein. Particularly with heart rates below 40/min, patients might also demonstrate findings consistent with decompensated heart failure, respiratory distress, and hypoprofusion such as diaphoresis, tachypnea, altered mental status, retraction, cool skin, and decreased capillary refill. 

Evaluation

Patients in complete heart block might present in significant distress. After stabilizing the patient, the most important component of the evaluation is the electrocardiogram. The electrocardiogram will have completely independent atrial and ventricular activity with no relation between the P wave and the QRS complex. The atrial rate, demonstrated by the P wave, should be faster than the ventricular rate, as demonstrated by the QRS complex. Depending on the location of the block, the QRS complex might be a narrow morphology (junctional escape QRS complex) or a wide morphology (ventricular escape QRS complex). An ECG should also have an evaluation for signs of ischemia. A basic metabolic panel should be obtained to correct electrolyte abnormalities and to evaluate and correct the glucose, which might be low in beta-blocker toxicity. Troponin should also have an evaluation and trended to check for myocardial infarction. In patients who take digoxin, a digoxin level must be obtained to exclude digoxin toxicity. A chest radiograph and complete blood count is necessary to evaluate for concomitant diseases. 

Treatment / Management

The initial management of bradycardic patients that are symptomatic usually begins with the use of intravenous atropine as per the advanced cardiac life support recommendations. Unfortunately, atropine acts at the AV node and, as such, is rarely effective in raising the heart rate in patients with complete heart block. Subsequently, medical options for the treatment of symptomatic bradycardia include dopamine and epinephrine, but both may serve as a temporary supporting measure only and might also be unsuccessful in improving the patient's heart rate in third-degree AV block. Often patients in third-degree heart block will require pacing. Transcutaneous pacing is more rapid, although both electrical and mechanical capture must be assured.

If transcutaneous pacing is not successful, a transvenous pacemaker is necessary. In stable patients, a cardiologist/electrophysiologist consultation for placement of a permanent pacemaker is most appropriate. Pacing may not be successful if underlying diseases causing the heart block do not receive treatment; this is particularly true in drug toxicity. In these patients, although the clinician might attempt pacing, the priority should be to treat the underlying cause. In patients with heart block secondary to an acute myocardial infarction, temporary pacing is a consideration in the cath lab. In patients with acute inferior infarct secondary to an occluded right coronary artery, timely restoration of arterial perfusion may often lead to improvement of the complete heart block. On the contrary, complete heart block related to an anterior infarction is more likely to eventually require placement of a permanent pacemaker than patients with inferior infarction. In a large recent study utilizing the National Inpatient Sample databases in patients with STEMI, the incidence of complete heart block was found to be approximately 2.2% in acute ST-elevation MI patients. It demonstrated that the in-hospital mortality was significantly higher in patients with complete heart block than those without it. Although the use of temporary pacing was higher in inferior MI patients, the need for an eventual permanent pacemaker was significantly higher in anterior MI patients.[6]

Regardless, cardiac catheterization and attempt for successful restoration of perfusion should not delay in patients with acute MI and complete heart block. Timely perfusion increases the likelihood of native rhythm restoration. 

Differential Diagnosis

Third-degree heart block is often a straightforward diagnosis on the 12-lead ECG and is characterized by the presence of a complete AV-dissociation, with an atrial rate being faster than the ventricular rate. It is crucial to differentiate complete heart block from AV dissociation related to other causes such as in idioventricular rhythms where the ventricular rate is faster than the atrial rates. Sometimes, second-degree heart block and high-degree AV blocks may masquerade as complete heart block. Repeating ECGs or longer rhythm strips are often helpful in making such a distinction.  

Prognosis

Long-term prognosis of third-degree AV block is not well studied (as it often requires treatment in acute settings). The prognosis likely is dependent on the patient's underlying disease burden and severity of the clinical presentation on arrival. Complete heart block is sometimes reversible in settings such as acute MI by restoring coronary perfusion and in conditions such as Lyme's disease by treatment with antibiotics. Historically, high-grade AV blocks have been considered a marker of poor prognosis in patients with ST-segment elevation myocardial infarction, and more recent studies indicate that this continues to be true in the era of percutaneous coronary intervention.[7] As previously mentioned, the presence of complete heart block in acute MI is an independent predictor for increased mortality in these patients. Complete heart block occurs more frequently in patients with inferior MI than anterior MI. Although the use of temporary pacing was higher in inferior MI patients, the need for an eventual permanent pacemaker was significantly higher in anterior MI patients. Also, the mortality associated with complete heart block is higher in patients with anterior MI compared to inferior MI.[6]

The recommendation is that a pacemaker is placed in patients with a persistent third-degree AV block, although the term "persistent" is often a matter of clinician judgment.[8] An Italian survey of just over 24000 patients found that 21% received pacing for third-degree AV blocks.[9] Although pacemaker is the definitive treatment for patients in third-degree AV block, it does carry some burden of heart failure itself. A 2017 study finding patients with AV blocks are more apt to develop heart failure than those without an AV block, both acutely (over 6 months) and chronically (6 months to 4 years), which may be related to the dependence of frequent RV pacing.[10]

Complications

Patients with third-degree heart blocks are vulnerable to decreased perfusion related to symptomatic bradycardia and decreased cardiac output. Patients may experience syncope related falls and head injuries. Critically ill patients may be unable to protect their airway and may develop nausea, possibly aspirate, and may have delirium. Treatment-related complications in the short term are malposition or dislodgement of a pacemaker lead and cardiac perforation in the short term and pacemaker associated heart failure in the long term. As is true for the prognosis of third-degree heart block, complications will frequently be dependent on a patient's overall health and compensatory mechanisms. 

Deterrence and Patient Education

Patient education should focus on diminishing the overall disease burden. Although not directly causative, underlying cardiac risk factors like diabetes mellitus and hypertension, as discussed above, are associated with an increased prevalence of third-degree AV block. Generally speaking, a focus on the overall cardiac health would be expected to improve the prognosis. 

After implantation of a permanent pacemaker, patients should have counsel about wound care and receive post-operative instructions. The patients should often refrain from driving for about 2 to 3 weeks and should use an arm-sling during the night and intermittently during the day to prevent any arm movement above the shoulder level. They should receive education regarding devices known to cause significant electromagnetic interference with the pacemaker, although this is less of a concern with newer-generation pacing devices available in the market. Patients should also be educated about periodic pacemaker check-ups including but not limited to lead function, lead thresholds, and battery life evaluation.

Enhancing Healthcare Team Outcomes

The management of patients with third-degree AV block requires interprofessional care coordination. The initial diagnosis often starts with the hospitalist, intensivist, or emergency department physician. The initial phase of stabilization of the critically ill patient with third-degree AV block requires close coordination and communication of the physician, nurses, and ancillary healthcare workers to carry out the principles of the bradycardia algorithm of advanced cardiac life support. If the patient is not currently in a critical care setting, the care teams must coordinate appropriate transportation to a critical care facility.

Nursing will assist with care irrespective of whether it is medical or if pacing is the choice of therapy. If medical, the nurses will coordinate with the pharmacist, who will verify all dosing and perform medication reconciliation, and report any concerns. Nursing will administer drugs (e.g., epinephrine) as well as monitor for effectiveness or adverse events.

Treatment of critically ill patients with third-degree AV block should be in either the emergency department, intensive care unit, or the cardiac catheterization laboratory. During and following the initial patient stabilization, coordination, and communication among physicians, nurses and ancillary staff is of utmost importance as the patient will require close monitoring and possibly rapid interventions if the clinical scenario changes. The primary care team needs to coordinate with consulting physicians, usually the intensivist and the cardiologist or electrophysiologist, to place the patient in a monitored setting or place a temporary intravenous pacer until an evaluation of the underlying etiology and the decision can be made to implant a permanent pacemaker. No evidence was discovered outlying the specific goals or practices to improve healthcare team performance, but typical procedures and policies used to activate critical care teams are necessary as appropriate to the healthcare setting.

Ultimately, third-degree AV block cases require an interprofessional team approach, including physicians, specialists, specialty-trained nurses, and pharmacists, all collaborating across disciplines to achieve optimal patient results. [Level V]

 


  • Image 11305 Not availableImage 11305 Not available
    Image courtesy O.Chaigasame
Attributed To: Image courtesy O.Chaigasame

Interested in Participating?

We are looking for contributors to author, edit, and peer review our vast library of review articles and multiple choice questions. In as little as 2-3 hours you can make a significant contribution to your specialty. In return for a small amount of your time, you will receive free access to all content and you will be published as an author or editor in eBooks, apps, online CME/CE activities, and an online Learning Management System for students, teachers, and program directors that allows access to review materials in over 500 specialties.

Improve Content - Become an Author or Editor

This is an academic project designed to provide inexpensive peer-reviewed Apps, eBooks, and very soon an online CME/CE system to help students identify weaknesses and improve knowledge. We would like you to consider being an author or editor. Please click here to learn more. Thank you for you for your interest, the StatPearls Publishing Editorial Team.

Third-Degree Atrioventricular Block - Questions

Take a quiz of the questions on this article.

Take Quiz
Of the following options, what is the most appropriate next step for a patient who develops the rhythm shown in the image following an anterior wall myocardial infarction but is hemodynamically stable?

(Move Mouse on Image to Enlarge)
  • Image 6747 Not availableImage 6747 Not available
    Image courtesy S Bhimji MD
Attributed To: Image courtesy S Bhimji MD



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A patient presents with sharp chest pain and altered mental status. His blood pressure is 80/56 mmHg, and a rhythm strip demonstrates the rhythm below. Despite oxygen, he is still dyspneic. What is the next best step in his management?

(Move Mouse on Image to Enlarge)
  • Image 9843 Not availableImage 9843 Not available
    By MoodyGroove at English Wikipedia - Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=18055698
Attributed To: By MoodyGroove at English Wikipedia - Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=18055698



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A 68-year-old man with a history of diabetes mellitus presents with fatigue, lightheadedness, and mild chest tightness. The rhythm is seen below. One dose of atropine is administered without a change in the rhythm. What is the next best step?

(Move Mouse on Image to Enlarge)
  • Image 9843 Not availableImage 9843 Not available
    By MoodyGroove at English Wikipedia - Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=18055698
Attributed To: By MoodyGroove at English Wikipedia - Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=18055698



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Atrioventricular block is very rare after the use of which medication?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A 70-year-old male presents to the emergency department after a syncopal episode. The patient's vital signs are temperature 37.4C, pulse 42/min, respiratory rate 20/min, and blood pressure 100/70mmHg. The patient is known to be on multiple medications for blood pressure control including beta-blockers and calcium channel blockers. There is no history of renal function impairment. Pill count demonstrates all medications have been taken as prescribed. The patient has a witnessed syncopal episode in the emergency department. Which investigation would be most useful and which treatment modality should be employed immediately upon results?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A patient comes to the emergency department with an ST-segment elevation MI of the anterior leads, shortly after you notice the rhythm as demonstrated on the strip provided. Which of the following is the definitive management of the rhythm seen?

(Move Mouse on Image to Enlarge)
  • Image 6747 Not availableImage 6747 Not available
    Image courtesy S Bhimji MD
Attributed To: Image courtesy S Bhimji MD



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A 67-year-old male is brought to the emergency department by EMS following a syncopal episode. Upon arrival, the patient is noted to be hypotensive with a blood pressure of 85/45mmHg and bradycardic with a heart rate of 32/min. On physical exam, the patient is awake and alert but complains of generalized weakness. ECG was performed which showed AV dissociation. Which treatment modality should be implemented in the emergency department urgently and continued during their inpatient stay for definitive management of the underlying cardiac condition?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
An elderly client is admitted after suffering a myocardial infarction. On the second day after admission, the monitor shows the rhythm below. What is true about this condition? Select all that apply.

(Move Mouse on Image to Enlarge)
  • Image 6471 Not availableImage 6471 Not available
    Contributed by Steve Bhmji, MS, MD, PhD
Attributed To: Contributed by Steve Bhmji, MS, MD, PhD



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A patient arrives at the emergency department with bradycardia. A rhythm strip demonstrates an atrial rate of 75 bpm with a ventricular rate of 35. The QRS is wide; the PR interval is variable, the ST segment and T-waves are not concerning for ST-elevation myocardial infarction. The patient has a history of hypertension for which she takes metoprolol and lisinopril. A transvenous pacer is placed in the emergency department with good mechanical capture. What is the next best step?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A patient arrives at the emergency department with shortness of breath and chest pain. A rhythm strip is obtained demonstrating the rhythm in the image. Three doses of 0.5 mg of atropine do improve the patient's condition. What is the next best step in the management of this patient?

(Move Mouse on Image to Enlarge)
  • Image 9843 Not availableImage 9843 Not available
    By MoodyGroove at English Wikipedia - Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=18055698
Attributed To: By MoodyGroove at English Wikipedia - Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=18055698



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A 63-year-old man presents with generalized fatigue. A rhythm strip and EKG are completed demonstrating the rhythm shown in the image. The patient has a blood pressure is 110/65 mmHg. Troponin, CBC, and basic metabolic profile are unremarkable. What is the next step?

(Move Mouse on Image to Enlarge)
  • Image 9843 Not availableImage 9843 Not available
    By MoodyGroove at English Wikipedia - Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=18055698
Attributed To: By MoodyGroove at English Wikipedia - Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=18055698



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A patient with a past medical history of hypertension taking amlodipine, metoprolol, losartan, and hydrochlorothiazide comes to the hospital with dizziness and altered mental status. The patient has the rhythm strip seen in the image. CBC results are WBC 10,000/microliter, hemoglobin 12 g/dL, hematocrit 36%, and platelets 200,000/microliter. Basic metabolic profile results are Na 137 mEq/L, Cl 100 mEq/L, BUN 10 mg/dL, K 4.0 mEq/L, CO2 24 mEq/L, creatinine 1.0 mg/dL, and glucose of 43 mg/dL. What is the most likely underlying cause of her symptoms

(Move Mouse on Image to Enlarge)
  • Image 9843 Not availableImage 9843 Not available
    By MoodyGroove at English Wikipedia - Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=18055698
Attributed To: By MoodyGroove at English Wikipedia - Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=18055698



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A 68-year-old male with a past medical history of hypertension and diabetes mellitus type 2 presents to the emergency department with dizziness and weakness. He takes nicardipine, metoprolol, losartan, and metformin at home. On examination, he is pale and diaphoretic. Vital signs reveal hypotension and bradycardia. An electrocardiogram is obtained, which is shown below. Laboratory workup was notable for elevated creatinine and hyperglycemia. Which of the following is the most likely cause of this patient's symptoms?

(Move Mouse on Image to Enlarge)
  • Image 9843 Not availableImage 9843 Not available
    By MoodyGroove at English Wikipedia - Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=18055698
Attributed To: By MoodyGroove at English Wikipedia - Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=18055698



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up

Third-Degree Atrioventricular Block - References

References

Kashou AH,Kashou HE, Rhythm, Atrioventricular Block 2019 Jan;     [PubMed]
OSTRANDER LD Jr,BRANDT RL,KJELSBERG MO,EPSTEIN FH, ELECTROCARDIOGRAPHIC FINDINGS AMONG THE ADULT POPULATION OF A TOTAL NATURAL COMMUNITY, TECUMSEH, MICHIGAN. Circulation. 1965 Jun;     [PubMed]
JOHNSON RL,AVERILL KH,LAMB LE, Electrocardiographic findings in 67,375 asymptomatic subjects. VII. Atrioventricular block. The American journal of cardiology. 1960 Jul;     [PubMed]
Movahed MR,Hashemzadeh M,Jamal MM, Increased prevalence of third-degree atrioventricular block in patients with type II diabetes mellitus. Chest. 2005 Oct;     [PubMed]
Benjamin EJ,Blaha MJ,Chiuve SE,Cushman M,Das SR,Deo R,de Ferranti SD,Floyd J,Fornage M,Gillespie C,Isasi CR,Jiménez MC,Jordan LC,Judd SE,Lackland D,Lichtman JH,Lisabeth L,Liu S,Longenecker CT,Mackey RH,Matsushita K,Mozaffarian D,Mussolino ME,Nasir K,Neumar RW,Palaniappan L,Pandey DK,Thiagarajan RR,Reeves MJ,Ritchey M,Rodriguez CJ,Roth GA,Rosamond WD,Sasson C,Towfighi A,Tsao CW,Turner MB,Virani SS,Voeks JH,Willey JZ,Wilkins JT,Wu JH,Alger HM,Wong SS,Muntner P, Heart Disease and Stroke Statistics-2017 Update: A Report From the American Heart Association. Circulation. 2017 Mar 7;     [PubMed]
Kosmidou I,Redfors B,Dordi R,Dizon JM,McAndrew T,Mehran R,Ben-Yehuda O,Mintz GS,Stone GW, Incidence, Predictors, and Outcomes of High-Grade Atrioventricular Block in Patients With ST-Segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention (from the HORIZONS-AMI Trial). The American journal of cardiology. 2017 May 1;     [PubMed]
Epstein AE,DiMarco JP,Ellenbogen KA,Estes NA 3rd,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, 2012 ACCF/AHA/HRS focused update incorporated into the ACCF/AHA/HRS 2008 guidelines for device-based therapy of cardiac rhythm abnormalities: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society. Circulation. 2013 Jan 22;     [PubMed]
Proclemer A,Zecchin M,D'Onofrio A,Ricci RP,Boriani G,Rebellato L,Ghidina M,Bianco G,Bernardelli E,Miconi A,Zorzin AF,Gregori D, [The Pacemaker and Implantable Cardioverter-Defibrillator Registry of the Italian Association of Arrhythmology and Cardiac Pacing - Annual report 2017]. Giornale italiano di cardiologia (2006). 2019 Mar;     [PubMed]
Merchant FM,Hoskins MH,Musat DL,Prillinger JB,Roberts GJ,Nabutovsky Y,Mittal S, Incidence and Time Course for Developing Heart Failure With High-Burden Right Ventricular Pacing. Circulation. Cardiovascular quality and outcomes. 2017 Jun;     [PubMed]
Harikrishnan P,Gupta T,Palaniswamy C,Kolte D,Khera S,Mujib M,Aronow WS,Ahn C,Sule S,Jain D,Ahmed A,Cooper HA,Jacobson J,Iwai S,Frishman WH,Bhatt DL,Fonarow GC,Panza JA, Complete Heart Block Complicating ST-Segment Elevation Myocardial Infarction: Temporal Trends and Association With In-Hospital Outcomes. JACC. Clinical electrophysiology. 2015 Dec     [PubMed]

Disclaimer

The intent of StatPearls is to provide practice questions and explanations to assist you in identifying and resolving knowledge deficits. These questions and explanations are not intended to be a source of the knowledge base of all of medicine, nor is it intended to be a board or certification review of Surgery-Podiatry Cert Medicine. The authors or editors do not warrant the information is complete or accurate. The reader is encouraged to verify each answer and explanation in several references. All drug indications and dosages should be verified before administration.

StatPearls offers the most comprehensive database of free multiple-choice questions with explanations and short review chapters ever developed. This system helps physicians, medical students, dentists, nurses, pharmacists, and allied health professionals identify education deficits and learn new concepts. StatPearls is not a board or certification review system for Surgery-Podiatry Cert Medicine, it is a learning system that you can use to help improve your knowledge base of medicine for life-long learning. StatPearls will help you identify your weaknesses so that when you are ready to study for a board or certification exam in Surgery-Podiatry Cert Medicine, you will already be prepared.

Our content is updated continuously through a multi-step peer review process that will help you be prepared and review for a thorough knowledge of Surgery-Podiatry Cert Medicine. When it is time for the Surgery-Podiatry Cert Medicine board and certification exam, you will already be ready. Besides online study quizzes, we also publish our peer-reviewed content in eBooks and mobile Apps. We also offer inexpensive CME/CE, so our content can be used to attain education credits while you study Surgery-Podiatry Cert Medicine.