DDxPro

In general, asymptomatic sinus bradycardia, sinus pauses, and first-degree AV block require no treatment. An exception is made to allow medical therapy for coexistent [tachyarrhythmias]. Second-degree Mobitz type I (Wenckebach) AV block often involves the AV node and carries a benign prognosis. Mobitz type II AV block is most often infranodal (within the bundle of His or the fascicles), is associated with fixed distal conduction system disease, and is likely to progress to complete heart block. Temporary followed by permanent pacing is recommended.
A 2:1 AV block can be in the AV node or in the distal conduction system. Prolongation of the PR interval with a narrow QRS complex suggests AV nodal block, whereas a wide complex QRS suggests distal conduction system disease. Third-degree AV block can be either congenital or acquired. A narrow escape can suggest that the location of the block is at the AV node (~50%) or the bundle of His (~50%). In cases with a wide escape, the block is usually infranodal (~80%), less stable, and in the rate of 30–45 bpm. Treatment with permanent pacemaker placement is recommended for patients with all forms of infranodal block, regardless of symptom status.

Management of bradycardia involves not only identification of symptoms and etiology but also the acuity of presentation.
Acutely, in cases of suspected AV node involvement, treat with atropine. Be aware that atropine may appear to worsen conduction in infranodal block.
Temporary transvenous pacing can be performed using a balloon-tipped catheter at the bedside or using a fixed catheter under fluoroscopic guidance. The indications for temporary pacing include both temporary treatment of reversible causes of symptomatic bradycardia and backup availability in those cases with high risk for development of complete heart block. Similarly, transcutaneous pacing may be used as an emergency method of pacing for symptomatic bradycardia. Early conversion to a transvenous system should be considered given discomfort of transcutaneous pacing and risk of intermittent noncapture. Note that temporary pacing has been shown to be ineffective in asystolic cardiac arrest and is not indicated.
In some patients, a beta blocker with intrinsic sympathomimetic activity (e.g., acebutolol, pindolol) may be of value in treating tachyarrhythmia with less bradyarrhythmia side effects. Because pharmacologic therapy for chronic conduction defects does not exist, the treatment of choice is either a temporary pacemaker for reversible causes or permanent pacemaker placement.
In many cases, permanent pacemaker implantation is considered for irreversible conditions, independent of the etiology. The serious risks of contemporary pacemaker implantation, a minor surgical procedure, are <1%. Because the endocardial leads are placed in the central venous circulation, it is critical that the patient be free of infection (e.g., urinary tract infections) prior to implantation because extraction of infected devices can have significant morbidity. At the time of consideration of pacing, thought must be given to the role of biventricular pacing (to improve symptoms with heart failure). A defibrillator (to reduce mortality) may be advisable if the patient has a depressed ejection fraction. Consultation with an electrophysiologist, implanting cardiologist, or surgeon familiar with current methodology is encouraged.

In general, asymptomatic sinus bradycardia, sinus pauses, and first-degree AV block require no treatment. An exception is made to allow medical therapy for coexistent [tachyarrhythmias]. Second-degree Mobitz type I (Wenckebach) AV block often involves the AV node and carries a benign prognosis. Mobitz type II AV block is most often infranodal (within the bundle of His or the fascicles), is associated with fixed distal conduction system disease, and is likely to progress to complete heart block. Temporary followed by permanent pacing is recommended.
A 2:1 AV block can be in the AV node or in the distal conduction system. Prolongation of the PR interval with a narrow QRS complex suggests AV nodal block, whereas a wide complex QRS suggests distal conduction system disease. Third-degree AV block can be either congenital or acquired. A narrow escape can suggest that the location of the block is at the AV node (~50%) or the bundle of His (~50%). In cases with a wide escape, the block is usually infranodal (~80%), less stable, and in the rate of 30–45 bpm. Treatment with permanent pacemaker placement is recommended for patients with all forms of infranodal block, regardless of symptom status.

Management of bradycardia involves not only identification of symptoms and etiology but also the acuity of presentation.
Acutely, in cases of suspected AV node involvement, treat with atropine. Be aware that atropine may appear to worsen conduction in infranodal block.
Temporary transvenous pacing can be performed using a balloon-tipped catheter at the bedside or using a fixed catheter under fluoroscopic guidance. The indications for temporary pacing include both temporary treatment of reversible causes of symptomatic bradycardia and backup availability in those cases with high risk for development of complete heart block. Similarly, transcutaneous pacing may be used as an emergency method of pacing for symptomatic bradycardia. Early conversion to a transvenous system should be considered given discomfort of transcutaneous pacing and risk of intermittent noncapture. Note that temporary pacing has been shown to be ineffective in asystolic cardiac arrest and is not indicated.
In some patients, a beta blocker with intrinsic sympathomimetic activity (e.g., acebutolol, pindolol) may be of value in treating tachyarrhythmia with less bradyarrhythmia side effects. Because pharmacologic therapy for chronic conduction defects does not exist, the treatment of choice is either a temporary pacemaker for reversible causes or permanent pacemaker placement.
In many cases, permanent pacemaker implantation is considered for irreversible conditions, independent of the etiology. The serious risks of contemporary pacemaker implantation, a minor surgical procedure, are <1%. Because the endocardial leads are placed in the central venous circulation, it is critical that the patient be free of infection (e.g., urinary tract infections) prior to implantation because extraction of infected devices can have significant morbidity. At the time of consideration of pacing, thought must be given to the role of biventricular pacing (to improve symptoms with heart failure). A defibrillator (to reduce mortality) may be advisable if the patient has a depressed ejection fraction. Consultation with an electrophysiologist, implanting cardiologist, or surgeon familiar with current methodology is encouraged.

In general, asymptomatic sinus bradycardia, sinus pauses, and first-degree AV block require no treatment. An exception is made to allow medical therapy for coexistent [tachyarrhythmias]. Second-degree Mobitz type I (Wenckebach) AV block often involves the AV node and carries a benign prognosis. Mobitz type II AV block is most often infranodal (within the bundle of His or the fascicles), is associated with fixed distal conduction system disease, and is likely to progress to complete heart block. Temporary followed by permanent pacing is recommended.
A 2:1 AV block can be in the AV node or in the distal conduction system. Prolongation of the PR interval with a narrow QRS complex suggests AV nodal block, whereas a wide complex QRS suggests distal conduction system disease. Third-degree AV block can be either congenital or acquired. A narrow escape can suggest that the location of the block is at the AV node (~50%) or the bundle of His (~50%). In cases with a wide escape, the block is usually infranodal (~80%), less stable, and in the rate of 30–45 bpm. Treatment with permanent pacemaker placement is recommended for patients with all forms of infranodal block, regardless of symptom status.

Management of bradycardia involves not only identification of symptoms and etiology but also the acuity of presentation.
Acutely, in cases of suspected AV node involvement, treat with atropine. Be aware that atropine may appear to worsen conduction in infranodal block.
Temporary transvenous pacing can be performed using a balloon-tipped catheter at the bedside or using a fixed catheter under fluoroscopic guidance. The indications for temporary pacing include both temporary treatment of reversible causes of symptomatic bradycardia and backup availability in those cases with high risk for development of complete heart block. Similarly, transcutaneous pacing may be used as an emergency method of pacing for symptomatic bradycardia. Early conversion to a transvenous system should be considered given discomfort of transcutaneous pacing and risk of intermittent noncapture. Note that temporary pacing has been shown to be ineffective in asystolic cardiac arrest and is not indicated.
In some patients, a beta blocker with intrinsic sympathomimetic activity (e.g., acebutolol, pindolol) may be of value in treating tachyarrhythmia with less bradyarrhythmia side effects. Because pharmacologic therapy for chronic conduction defects does not exist, the treatment of choice is either a temporary pacemaker for reversible causes or permanent pacemaker placement.
In many cases, permanent pacemaker implantation is considered for irreversible conditions, independent of the etiology. The serious risks of contemporary pacemaker implantation, a minor surgical procedure, are <1%. Because the endocardial leads are placed in the central venous circulation, it is critical that the patient be free of infection (e.g., urinary tract infections) prior to implantation because extraction of infected devices can have significant morbidity. At the time of consideration of pacing, thought must be given to the role of biventricular pacing (to improve symptoms with heart failure). A defibrillator (to reduce mortality) may be advisable if the patient has a depressed ejection fraction. Consultation with an electrophysiologist, implanting cardiologist, or surgeon familiar with current methodology is encouraged.

In general, asymptomatic sinus bradycardia, sinus pauses, and first-degree AV block require no treatment. An exception is made to allow medical therapy for coexistent [tachyarrhythmias]. Second-degree Mobitz type I (Wenckebach) AV block often involves the AV node and carries a benign prognosis. Mobitz type II AV block is most often infranodal (within the bundle of His or the fascicles), is associated with fixed distal conduction system disease, and is likely to progress to complete heart block. Temporary followed by permanent pacing is recommended.
A 2:1 AV block can be in the AV node or in the distal conduction system. Prolongation of the PR interval with a narrow QRS complex suggests AV nodal block, whereas a wide complex QRS suggests distal conduction system disease. Third-degree AV block can be either congenital or acquired. A narrow escape can suggest that the location of the block is at the AV node (~50%) or the bundle of His (~50%). In cases with a wide escape, the block is usually infranodal (~80%), less stable, and in the rate of 30–45 bpm. Treatment with permanent pacemaker placement is recommended for patients with all forms of infranodal block, regardless of symptom status.

Management of bradycardia involves not only identification of symptoms and etiology but also the acuity of presentation.
Acutely, in cases of suspected AV node involvement, treat with atropine. Be aware that atropine may appear to worsen conduction in infranodal block.
Temporary transvenous pacing can be performed using a balloon-tipped catheter at the bedside or using a fixed catheter under fluoroscopic guidance. The indications for temporary pacing include both temporary treatment of reversible causes of symptomatic bradycardia and backup availability in those cases with high risk for development of complete heart block. Similarly, transcutaneous pacing may be used as an emergency method of pacing for symptomatic bradycardia. Early conversion to a transvenous system should be considered given discomfort of transcutaneous pacing and risk of intermittent noncapture. Note that temporary pacing has been shown to be ineffective in asystolic cardiac arrest and is not indicated.
In some patients, a beta blocker with intrinsic sympathomimetic activity (e.g., acebutolol, pindolol) may be of value in treating tachyarrhythmia with less bradyarrhythmia side effects. Because pharmacologic therapy for chronic conduction defects does not exist, the treatment of choice is either a temporary pacemaker for reversible causes or permanent pacemaker placement.
In many cases, permanent pacemaker implantation is considered for irreversible conditions, independent of the etiology. The serious risks of contemporary pacemaker implantation, a minor surgical procedure, are <1%. Because the endocardial leads are placed in the central venous circulation, it is critical that the patient be free of infection (e.g., urinary tract infections) prior to implantation because extraction of infected devices can have significant morbidity. At the time of consideration of pacing, thought must be given to the role of biventricular pacing (to improve symptoms with heart failure). A defibrillator (to reduce mortality) may be advisable if the patient has a depressed ejection fraction. Consultation with an electrophysiologist, implanting cardiologist, or surgeon familiar with current methodology is encouraged.

In general, asymptomatic sinus bradycardia, sinus pauses, and first-degree AV block require no treatment. An exception is made to allow medical therapy for coexistent [tachyarrhythmias]. Second-degree Mobitz type I (Wenckebach) AV block often involves the AV node and carries a benign prognosis. Mobitz type II AV block is most often infranodal (within the bundle of His or the fascicles), is associated with fixed distal conduction system disease, and is likely to progress to complete heart block. Temporary followed by permanent pacing is recommended.
A 2:1 AV block can be in the AV node or in the distal conduction system. Prolongation of the PR interval with a narrow QRS complex suggests AV nodal block, whereas a wide complex QRS suggests distal conduction system disease. Third-degree AV block can be either congenital or acquired. A narrow escape can suggest that the location of the block is at the AV node (~50%) or the bundle of His (~50%). In cases with a wide escape, the block is usually infranodal (~80%), less stable, and in the rate of 30–45 bpm. Treatment with permanent pacemaker placement is recommended for patients with all forms of infranodal block, regardless of symptom status.

Management of bradycardia involves not only identification of symptoms and etiology but also the acuity of presentation.
Acutely, in cases of suspected AV node involvement, treat with atropine. Be aware that atropine may appear to worsen conduction in infranodal block.
Temporary transvenous pacing can be performed using a balloon-tipped catheter at the bedside or using a fixed catheter under fluoroscopic guidance. The indications for temporary pacing include both temporary treatment of reversible causes of symptomatic bradycardia and backup availability in those cases with high risk for development of complete heart block. Similarly, transcutaneous pacing may be used as an emergency method of pacing for symptomatic bradycardia. Early conversion to a transvenous system should be considered given discomfort of transcutaneous pacing and risk of intermittent noncapture. Note that temporary pacing has been shown to be ineffective in asystolic cardiac arrest and is not indicated.
In some patients, a beta blocker with intrinsic sympathomimetic activity (e.g., acebutolol, pindolol) may be of value in treating tachyarrhythmia with less bradyarrhythmia side effects. Because pharmacologic therapy for chronic conduction defects does not exist, the treatment of choice is either a temporary pacemaker for reversible causes or permanent pacemaker placement.
In many cases, permanent pacemaker implantation is considered for irreversible conditions, independent of the etiology. The serious risks of contemporary pacemaker implantation, a minor surgical procedure, are <1%. Because the endocardial leads are placed in the central venous circulation, it is critical that the patient be free of infection (e.g., urinary tract infections) prior to implantation because extraction of infected devices can have significant morbidity. At the time of consideration of pacing, thought must be given to the role of biventricular pacing (to improve symptoms with heart failure). A defibrillator (to reduce mortality) may be advisable if the patient has a depressed ejection fraction. Consultation with an electrophysiologist, implanting cardiologist, or surgeon familiar with current methodology is encouraged.

In general, asymptomatic sinus bradycardia, sinus pauses, and first-degree AV block require no treatment. An exception is made to allow medical therapy for coexistent [tachyarrhythmias]. Second-degree Mobitz type I (Wenckebach) AV block often involves the AV node and carries a benign prognosis. Mobitz type II AV block is most often infranodal (within the bundle of His or the fascicles), is associated with fixed distal conduction system disease, and is likely to progress to complete heart block. Temporary followed by permanent pacing is recommended.
A 2:1 AV block can be in the AV node or in the distal conduction system. Prolongation of the PR interval with a narrow QRS complex suggests AV nodal block, whereas a wide complex QRS suggests distal conduction system disease. Third-degree AV block can be either congenital or acquired. A narrow escape can suggest that the location of the block is at the AV node (~50%) or the bundle of His (~50%). In cases with a wide escape, the block is usually infranodal (~80%), less stable, and in the rate of 30–45 bpm. Treatment with permanent pacemaker placement is recommended for patients with all forms of infranodal block, regardless of symptom status.

Management of bradycardia involves not only identification of symptoms and etiology but also the acuity of presentation.
Acutely, in cases of suspected AV node involvement, treat with atropine. Be aware that atropine may appear to worsen conduction in infranodal block.
Temporary transvenous pacing can be performed using a balloon-tipped catheter at the bedside or using a fixed catheter under fluoroscopic guidance. The indications for temporary pacing include both temporary treatment of reversible causes of symptomatic bradycardia and backup availability in those cases with high risk for development of complete heart block. Similarly, transcutaneous pacing may be used as an emergency method of pacing for symptomatic bradycardia. Early conversion to a transvenous system should be considered given discomfort of transcutaneous pacing and risk of intermittent noncapture. Note that temporary pacing has been shown to be ineffective in asystolic cardiac arrest and is not indicated.
In some patients, a beta blocker with intrinsic sympathomimetic activity (e.g., acebutolol, pindolol) may be of value in treating tachyarrhythmia with less bradyarrhythmia side effects. Because pharmacologic therapy for chronic conduction defects does not exist, the treatment of choice is either a temporary pacemaker for reversible causes or permanent pacemaker placement.
In many cases, permanent pacemaker implantation is considered for irreversible conditions, independent of the etiology. The serious risks of contemporary pacemaker implantation, a minor surgical procedure, are <1%. Because the endocardial leads are placed in the central venous circulation, it is critical that the patient be free of infection (e.g., urinary tract infections) prior to implantation because extraction of infected devices can have significant morbidity. At the time of consideration of pacing, thought must be given to the role of biventricular pacing (to improve symptoms with heart failure). A defibrillator (to reduce mortality) may be advisable if the patient has a depressed ejection fraction. Consultation with an electrophysiologist, implanting cardiologist, or surgeon familiar with current methodology is encouraged.

The presence of preexcitation warrants referral to an electrophysiologist for evaluation of the appropriateness of diagnostic electrophysiologic study (EPS) and possible catheter ablation in the setting of preexcitation and potential atrioventricular reciprocating tachycardia (AVRT). If preexcitation is not clearly manifest, significant symptoms, particularly syncope, also warrant evaluation by an electrophysiologist.

The presence of preexcitation warrants referral to an electrophysiologist for evaluation of the appropriateness of diagnostic electrophysiologic study (EPS) and possible catheter ablation in the setting of preexcitation and potential atrioventricular reciprocating tachycardia (AVRT). If preexcitation is not clearly manifest, significant symptoms, particularly syncope, also warrant evaluation by an electrophysiologist.

If P waves are not clearly visible during tachycardia [No visible P waves], {AVNRT} is likely because typical AVNRT using ante-grade slow pathway conduction and retrograde fast pathway conduction usually results in P waves “buried” in the QRS complex. If [more P waves than R waves] are present (i.e., the atrial rate exceeds the ventricular rate), {atrial tachycardia} or {atrial flutter} are likely because this finding demonstrates that the AV node is not necessary to maintain the tachycardia circuit. If there is a 1:1 relationship between P and R waves, analysis should then proceed to the RP interval.

[No visible P waves]