7/6/23, 2:50 PM Arrhythmia management for the primary care clinician - UpToDate Official reprint from UpToDate www.uptodate.com 2023 UpToDate, Inc. and/or its affiliates. All Rights Reserved. Arrhythmia management for the primary care clinician : Samuel L vy, MD, Brian Olshansky, MD : Hugh Calkins, MD : Susan B Yeon, MD, JD, FACC All topics are updated as new evidence becomes available and our peer review process is complete. Literature review current through: Jun 2023. This topic last updated: Dec 03, 2021. INTRODUCTION Clinicians in many disciplines commonly face the problem of evaluating and treating patients with cardiac arrhythmias ( table 1). Carefully performed randomized trials, technological advances, and better understanding of arrhythmia mechanisms using intracardiac recordings and programmed electrical stimulation and mapping techniques have resulted in improved approaches to rhythm disturbances. Basic evaluation and management principles are key to the initial approach to the patient with an arrhythmia. There are several reasons to evaluate and treat arrhythmias: Eliminate symptoms and improve abnormal hemodynamics which can result from arrhythmias. Prevent imminent death and hemodynamic compromise due to a life-threatening arrhythmia. To assess the patient's risk of potentially developing a life-threatening arrhythmia, thereby allowing for possible preventive measures. (See "Primary prevention of sudden cardiac death in patients with cardiomyopathy and heart failure with reduced LVEF".) Reduce possible risks other than the direct effects of the arrhythmia (eg, reduce stroke in patients with atrial fibrillation). This topic will provide an overview of early diagnosis and management of rhythm disturbances in patients who present to primary care clinicians (PCCs). The reader will be referred to detailed https://www.uptodate.com/contents/arrhythmia-management-for-the-primary-care-clinician/print 1/34 7/6/23, 2:50 PM Arrhythmia management for the primary care clinician - UpToDate discussions of the individual arrhythmias. The role of the PCC in the evaluation of palpitations is discussed separately. (See "Evaluation of palpitations in adults".) DEFINITION An arrhythmia is any rhythm that is not normal sinus rhythm with normal atrioventricular (AV) conduction. Normal sinus rhythm originates from the sinus node in the upper portion of the right atrium. During sinus rhythm, the heart rate is in the normal range, the P waves are normal on the electrocardiogram (ECG), and the rate is stable. The normal sinus rate at rest has been considered to be between 60 and 100 beats per minute (bpm). However, the range (defined by two standard deviations from the mean) is between 43 and 93 bpm for men and 52 and 94 bpm for women. Sinus bradycardia or tachycardia may be physiologic (ie, normal) or nonphysiologic (ie, abnormal); each is discussed separately. (See "Sinus bradycardia" and "Sinus tachycardia: Evaluation and management".) Not uncommonly, the activation rate of the sinus node varies, leading to a variable P-P interval on the ECG. If the variation of the P-P interval is 0.12 sec (120 ms) or more in the presence of normal P waves, this is known as sinus arrhythmia. Sinus arrhythmia is usually physiologic and is related to respiratory cycles. It does not require treatment. (See "Normal sinus rhythm and sinus arrhythmia" and "Etiology of atrioventricular block".) ECG documentation, age of the patient, and the clinical context in which the arrhythmia occurs are critical to the proper management. COMMON ARRHYTHMIAS Common arrhythmias encountered in an office-based setting include: Premature atrial complex (PAC; also referred to a premature atrial beat, premature supraventricular complex, or premature supraventricular beat). Ventricular premature beats (VPBs) ( waveform 1). Bradycardias ( waveform 2), including sinus bradycardia ( waveform 2 and table 2). Ventricular tachycardia ( waveform 3A-B). Atrial fibrillation (AF) and atrial flutter ( waveform 4A-B). https://www.uptodate.com/contents/arrhythmia-management-for-the-primary-care-clinician/print 2/34 7/6/23, 2:50 PM Arrhythmia management for the primary care clinician - UpToDate Supraventricular tachycardia (SVTs) ( waveform 5 and figure 1). AV block ( waveform 6). Nonsustained ventricular tachycardia (NSVT) ( waveform 7). Follow-up of already treated VT or ventricular fibrillation (VF). The diagnosis of these arrhythmias may be difficult, even for an experienced specialist in rhythm disturbances. As an example, the etiology of wide or narrow QRS tachycardias may be difficult to determine based upon the 12-lead ECG. (See "Wide QRS complex tachycardias: Approach to the diagnosis" and "Narrow QRS complex tachycardias: Clinical manifestations, diagnosis, and evaluation".) Some rhythm disturbances, such as symptomatic bradycardia (with syncope or near syncope), rapid rates in atrial fibrillation, or sustained ventricular tachycardia, require urgent attention. Others, such as ectopic atrial and ventricular beats, may cause concern but do not need immediate management. In some cases, these concerning arrhythmias may be a sign of underlying cardiovascular pathology that requires attention more than the rhythm disturbance itself (eg, conditions like arrhythmogenic right ventricular cardiomyopathy, hypertrophic cardiomyopathy, etc). ROLE OF THE PCC IN LONG-TERM CARE The role of the primary care clinician (PCC) in the long-term care of patients with arrhythmias depends upon the particular arrhythmia diagnosis and treatment. All patients should be queried at each routine visit about changes in symptoms relevant to the arrhythmia and its treatment. Frequently, it becomes difficult to determine if a rhythm disturbance is benign or potentially serious and life-threatening. Furthermore, the association of symptoms with a rhythm disturbance can be confusing. As such, consultation with a cardiologist or an electrophysiologist may be required to help make the diagnosis and help with risk stratification. Commonly, the PCC can work in collaboration with long-term follow-up of the patient who has rhythm disturbances after the diagnosis is secured and an initial management has been undertaken. Patients with pacemakers, implantable cardioverter defibrillators, or cardiac resynchronization therapy are best followed periodically and evaluated by clinicians knowledgeable in device programming, device characteristics, and complications. Patients prescribed antiarrhythmic drug therapy, or those who have undergone an interventional procedure or catheter ablation therapy, are generally followed by a cardiologist https://www.uptodate.com/contents/arrhythmia-management-for-the-primary-care-clinician/print 3/34 7/6/23, 2:50 PM Arrhythmia management for the primary care clinician - UpToDate and/or cardiac electrophysiologist in collaboration with the PCC. APPROACH TO THE PATIENT Patients typically seek medical care for symptoms associated with an arrhythmia. In addition, some asymptomatic arrhythmias and findings require careful evaluation and management. An abnormal ECG that shows a rhythm disturbance different from sinus rhythm even in an asymptomatic patient requires careful assessment to determine long-term risks of symptoms and potential life-threatening outcomes. Occasionally, an asymptomatic patient who has an irregular pulse on examination, or who has an ECG, ambulatory monitor, or exercise test for another reason is found to have an arrhythmia or evidence that may indicate an arrhythmia may be present. Patients may also be referred for evaluation if they have a finding or condition associated with risk of arrhythmia, such as a short PR interval, a delta wave, a long QT interval on an ECG, or hypertrophic cardiomyopathy identified by an echocardiogram. Additionally, patients who have evidence of heart failure (HF) may be at risk for potentially serious and life-threatening rhythm disturbances that require more in-depth evaluation and assessment. In addition, individuals with family history of sudden death or heritable genetic syndromes (long QT syndrome, Brugada syndrome, arrhythmogenic right ventricular cardiomyopathy) are referred for arrhythmia evaluation, as discussed separately. (See "Congenital long QT syndrome: Diagnosis" and "Brugada syndrome or pattern: Management and approach to screening of relatives", section on 'Screening relatives' and "Arrhythmogenic right ventricular cardiomyopathy: Diagnostic evaluation and diagnosis", section on 'Screening of family members'.) The initial evaluation of the patient with an arrhythmia consists of a complete history (aimed toward symptoms and timing of the arrhythmia and potential underlying diseases), physical examination, and 12-lead ECG, if possible, during the arrhythmia and without it. The ECG alone during the arrhythmia may determine the type of arrhythmia and whether a particular symptom is related to the arrhythmia. Symptoms The presence and type of symptoms may determine whether any action needs to be taken. Symptoms may be related to the arrhythmia (eg, palpitations) or due to the hemodynamic consequences of the arrhythmias (eg, dyspnea, dizziness, or syncope). Symptoms caused by cardiac arrhythmias can mimic those due to other medical disorders and include palpitations, dizziness, lightheadedness, syncope, chest discomfort, neck discomfort, https://www.uptodate.com/contents/arrhythmia-management-for-the-primary-care-clinician/print 4/34 7/6/23, 2:50 PM Arrhythmia management for the primary care clinician - UpToDate dyspnea, weakness, and anxiety. Secondary consequences of arrhythmias, often due to underlying heart disease, are an additional source of symptoms (eg, HF, ischemia, and thromboemboli). Cardiac arrhythmias can have unusual symptomatic presentations such as tinnitus, visual changes, increased urinary frequency, abdominal discomfort, and peripheral edema. Arrhythmias may cause a change in sympathetic and vagal tone, hormonal changes, elevation of venous pressure, and reduced cardiac output, all of which can lead to an even longer list of other symptoms. Symptom type and severity are related to the etiology and rate of the arrhythmia, and to the nature and severity of underlying cardiovascular disease and concurrent conditions. The symptom severity often dictates the urgency for therapy or even the need to evaluate and treat. The presence of structural heart disease is a key issue that determines the urgency of intervention, evaluation, therapy, and the prognostic importance of the arrhythmia. Arrhythmias commonly cause palpitations. The approach to the patient who presents with palpitations is found elsewhere. (See "Evaluation of palpitations in adults".) Diagnosis While the patient's age, medical history, and physical exam may strongly suggest the diagnosis, such as in a patient with lightheadedness and a rapid and irregularly irregular pulse (atrial fibrillation), the diagnosis requires documentation with an ECG or a monitor. (See "ECG tutorial: Atrial and atrioventricular nodal (supraventricular) arrhythmias" and "ECG tutorial: Atrioventricular block" and "ECG tutorial: Basic principles of ECG analysis" and "ECG tutorial: Intraventricular block" and "ECG tutorial: Rhythms and arrhythmias of the sinus node" and "ECG tutorial: Ventricular arrhythmias".) Many patients with a suspected arrhythmia have a paroxysmal pattern, so that the ECG recorded in the absence of symptoms is either normal or does not suggest a specific arrhythmia. Four types of outpatient monitoring systems are available (see "Ambulatory ECG monitoring"): Traditional Holter Continuous recording of ECG, usually for 24 or 48 hours. Event recorder Patient activated recorder, although some newer models have automatic arrhythmia detection software to store asymptomatic episodes. Data is transmitted over the phone to a monitoring station. Mobile continuous outpatient cardiac telemetry Continuous recording and analysis, with symptomatic or algorithm defined episodes transmitted automatically via cellular technology to monitoring station. https://www.uptodate.com/contents/arrhythmia-management-for-the-primary-care-clinician/print 5/34 7/6/23, 2:50 PM Arrhythmia management for the primary care clinician - UpToDate Insertable cardiac monitor Patient and algorithm defined episodes stored in device, until interrogated either in office or remotely via home equipment and internet. Ambulatory monitoring to assess for arrhythmia is frequently indicated in the evaluation of patients with syncope [1]. An event recorder or transtelephonic monitor can help make the diagnosis in a patient with less frequent palpitations [2]. Transtelephonic ECG devices exist in several forms of recorders and transmitters capable of direct transmission of an ECG as an audio signal by telephone. These ECG signals are most commonly received at a base station equipped with a demodulator and an ECG strip chart recorder. Although such devices usually provide limited, noncontinuous sample ECG data, the device may be used in either a noncontinuous or continuous format. Transtelephonic devices with memory that record and are applied non-continuously are small (beeper size), lightweight instruments that are generally inexpensive. These devices are carried by the patient; they can be applied with temporary contact to the precordial area, or are attached by electrodes and worn continuously. The memory feature allows recording of data without the need for immediate access to telephone transmission. Transtelephonic monitoring includes wrist recorders whose circuitry is completed by contact of the index finger and thumb, or hand contact to the opposite wrist. This action results in the loop storage of a four- to five-minute ECG sample of lead I, and permits direct printout or transtelephonic transmission. The stored data may be transmitted by telephone directly to a facsimile machine. An implantable monitor (Reveal, Medtronic, Minneapolis, United States) is available in Europe and will be available soon in the United States. (See "Ambulatory ECG monitoring".) New patch monitors have become available that can record over a period of several weeks of data. Smartphone apps have been used to revolutionize external recording techniques and to detect atrial fibrillation. Other over-the-counter monitoring approaches (using certain types of watches) and other types of electrodes coupled to cell phones are now being used to detect atrial fibrillation and other rhythm disturbances. If episodes are associated with exercise or physical or mental stress or when an arrhythmia cannot be documented with ambulatory or transtelephonic monitoring, a treadmill or bicycle ergometer may be helpful to establish the presence and mechanism of the arrhythmia, particularly if the arrhythmia is triggered by exercise. In some instances, the rhythm disturbance is simply a lack of change in the heart rate with exercise or with excessive heart rates during exercise. https://www.uptodate.com/contents/arrhythmia-management-for-the-primary-care-clinician/print 6/34 7/6/23, 2:50 PM Arrhythmia management for the primary care clinician - UpToDate In some instances, such as in selected patients with unexplained syncope, an insertable cardiac monitor (sometimes referred to as an implantable cardiac monitor or an implantable loop recorder) may be indicated to detect the arrhythmia that may be responsible for patient symptoms based on the correlation between the symptoms and the recorded arrhythmias. (See "Ambulatory ECG monitoring", section on 'Insertable cardiac monitor'.) Patients identified with an arrhythmia For any patient with a diagnosed arrhythmia, several questions should be considered and hopefully answered in short order: Which arrhythmia(s) is present? Does the arrhythmia pose an immediate or long-term risk to the patient? Is the arrhythmia well-tolerated (based on symptoms and blood pressure)? Does the arrhythmia require immediate intervention, such as medical therapy or cardioversion? Does the patient require urgent hospitalization for the arrhythmia and/or associated underlying conditions (eg, underlying heart disease)? Is specialist consultation required, and if so, when? Should anticoagulation and/or other medical therapy be started and when? Asymptomatic patients Patients with asymptomatic arrhythmias rarely require urgent treatment, but evaluation of the arrhythmia is important to determine its clinical significance and appropriate management. In patients who have low risk for serious outcomes, a clinician may choose to refer the patient on an elective basis to a cardiologist or cardiac electrophysiologist. Additionally, the arrhythmias needs to be understood in light of any underlying medical diagnosis. For example, occasional asymptomatic PVCs may have little importance in young, otherwise healthy individuals but may portend a poor prognosis in patients with HF and cardiomyopathy. Symptomatic patients For patients who are symptomatic in the office, the testing strategy is based on an understanding of the suspected cause for the symptoms and symptom severity. The management strategy will depend both on the characteristics of the symptoms and the type of arrhythmia present if diagnosed. In the following clinical scenarios, we recommend urgent transfer to a facility with emergency care capabilities: Syncope or near syncope in patients with high degree AV block (ie, Mobitz type II second degree or third degree [complete] AV block) or bradycardia. https://www.uptodate.com/contents/arrhythmia-management-for-the-primary-care-clinician/print 7/34 7/6/23, 2:50 PM Arrhythmia management for the primary care clinician - UpToDate Wide complex sustained rhythms (other than sinus with bundle branch block) including ventricular tachycardia especially if not well tolerated or associated with hypotension. Patients in whom the diagnosis is uncertain after examination and ECG, but for whom there is a concern about a life-threatening arrhythmia. Patients with a history of heart disease (including coronary artery disease, cardiomyopathy, or HF) who present with syncope, near syncope, and/or documented ventricular arrhythmia. Sustained supraventricular tachycardia (SVT). Atrial fibrillation or flutter with rapid or slow rates. Arrhythmias associated with chest pain, dyspnea or HF. Emergent cardioversion is not indicated for any conscious patient, including those with ventricular tachycardia, except if it is associated with hemodynamic compromise (systolic blood pressure [SBP] <80 mmHg). However, urgent cardioversion may be required if the rhythm is not tolerated well. Cardioversion has risks and should not be undertaken if there is a risk of a thromboembolic event that could be precipitated by electrical shock. Such may be the case for a patient who is not adequately anticoagulated and in atrial fibrillation for more than 24 hours. (See "Cardioversion for specific arrhythmias" and "Atrial fibrillation: Cardioversion".) Referral to a specialist Arrhythmias such as isolated PACs or ventricular premature beats (VPBs), or atrial fibrillation, are common in the general population and many primary care clinicians (PCC) are comfortable and capable of managing patients with these. We suggest elective referral to a cardiologist for the following patients: Any patient with an arrhythmia when the PCC is uncomfortable with either diagnosis or management. Candidates for permanent pacing. Those with an uncertain diagnosis, prognosis, or management strategy. Patients with wide QRS complex tachycardia of uncertain cause should generally be referred to a clinical electrophysiologist to define appropriate evaluation (such as an electrophysiologic study) and management. Patients with structural heart disease and ventricular arrhythmia should generally be referred to an electrophysiologist. Those who might benefit from implantation of a pacemaker, an implantable cardioverter defibrillator, or biventricular device (cardiac resynchronization therapy [CRT]). https://www.uptodate.com/contents/arrhythmia-management-for-the-primary-care-clinician/print 8/34 7/6/23, 2:50 PM Arrhythmia management for the primary care clinician - UpToDate Those who might benefit from a catheter ablation procedure. Those who might benefit from antiarrhythmic drug therapy (eg, particularly patients with structural heart disease). Those who have a confusing picture, difficult to interpret ECG, or unusual findings on a monitor. THERAPEUTIC CONSIDERATIONS The goal of therapy for any arrhythmia is to improve symptoms and to prevent a potentially serious outcome, primarily a life-threatening arrhythmia and sudden death. Stroke prevention in patients with atrial fibrillation and atrial flutter is also an important treatment objective. The decision to initiate a long-term treatment strategy, whether it be with device or drug therapy, depends upon the severity and frequency of arrhythmia-related symptoms compared to the risks associated with the therapy itself. The need for long-term therapy must be carefully individualized to each patient since the severity and importance of symptoms are highly variable. The symptoms associated with any arrhythmia can have an impact on lifestyle, occupation, driving, and other important daily activities. In most cases, initiation of antiarrhythmic drug therapy will be guided by a cardiologist or cardiac electrophysiologist. Pacemakers, implantable cardioverter-defibrillators (ICDs), and biventricular devices are generally implanted by electrophysiologists or other clinicians with special training and certification in their placement. The ability to interrogate the devices long term is also necessary. The long-term follow-up of patients with implanted devices also requires special training and expertise. Antiarrhythmic drugs We suggest the involvement of a specialist (cardiologist or electrophysiologist) when initiation of any antiarrhythmic drug is considered. Antiarrhythmic drugs have the potential to increase premature ventricular contractions or induce or aggravate monomorphic ventricular tachycardia (VT), torsades de pointes, ventricular fibrillation (VF), conduction disturbances, or bradycardia. This phenomenon is known as proarrhythmia ( table 3). The potential for major adverse outcomes, including death, requires the expertise of a specialist who understands the use and risks of these drugs. (See "Cardiac excitability, mechanisms of arrhythmia, and action of antiarrhythmic drugs".) https://www.uptodate.com/contents/arrhythmia-management-for-the-primary-care-clinician/print 9/34 7/6/23, 2:50 PM Arrhythmia management for the primary care clinician - UpToDate The risk of proarrhythmia is higher for class I drugs ( table 4) in patients with structural heart disease, especially coronary heart disease and/or left ventricular dysfunction, than in patients with structurally normal heart disease. Class II drugs (beta blockers, except sotalol, which also has class III properties at higher dosing), have no proarrhythmic effects but can cause bradycardia. Class III drugs prolong repolarization and pose the specific risk of torsades de pointes or ventricular tachycardia. Although the exact incidence of proarrhythmia is not certain, it appears to be relatively low when antiarrhythmic drugs are used carefully and properly. The risk varies according to the type of arrhythmia treated, the presence of structural heart disease, the QT interval, pre-existing conduction disturbances, sinus node dysfunction, patient age, the presence of HF, and left and right ventricular function. The proarrhythmic risk is highest in patients with depressed left ventricular function (eg, ejection fraction [EF] <0.30), the group at highest risk for an arrhythmic event and sudden death and in case of ionic disturbance (hypokalemia); the risk is lowest in those with no organic heart disease. Proarrhythmia can be predictable and is most often idiosyncratic. However, it may be dose- related for specific drugs, including sotalol, dofetilide, class IC drugs, and the metabolite of procainamide, N-acetyl procainamide. Torsades de pointes is the most recognized form of drug proarrhythmia. It is characterized by a VT with a twisting of the peaks of the QRS complexes across an imaginary isoelectric line ( waveform 8A-C). The QT interval is prolonged, bradycardia is often present, and the arrhythmia is induced after a short-long cycle. Torsades de pointes was originally recognized as a complication of quinidine use, being the mechanism for "quinidine syncope." Many non- antiarrhythmic drugs, including some antibiotics, antipsychotics, and other classes of drugs, can increase the risk of torsades de pointes via prolongation of the QT interval ( table 5). (See "Acquired long QT syndrome: Definitions, pathophysiology, and causes".) Initiation of therapy Therapy with some (but not all) antiarrhythmic drugs is best initiated in the hospital, primarily to monitor for early proarrhythmia. The decision to hospitalize depends upon several factors: The presence and severity of structural heart disease. The indication for treatment (eg, etiology of the arrhythmia and type and severity of associated symptoms). Treatment for ventricular tachycardia is usually started in the hospital. https://www.uptodate.com/contents/arrhythmia-management-for-the-primary-care-clinician/print 10/34 7/6/23, 2:50 PM Arrhythmia management for the primary care clinician - UpToDate The drug used. For example, the labeling information for dofetilide and sotalol specify inpatient initiation, while flecainide, propafenone, dronedarone, and amiodarone can generally be initiated outside the hospital in appropriate patients. Following the initiation of an antiarrhythmic drug, patients should have periodic monitoring with an ECG and laboratory tests. The frequency of such tests is higher at the time of initiation and dose adjustment. Careful monitoring of electrolytes may help reduce the risk of proarrhythmia. Assessment of renal and/or hepatic function is also important depending on the agent(s) being used. These drugs may interact with other drugs, which also require monitoring (for example, amiodarone tends to increase the International Normalized Ratio [INR] and digoxin level) Patients taking amiodarone should have assessment of hepatic, thyroid, and pulmonary function on a regular basis, or with any symptoms that suggest possible organ toxicity. Patients taking amiodarone should also be cautioned regarding skin photosensitivity. Class IC antiarrhythmic drugs should be avoided in patients with ventricular dysfunction (given their negative inotropic effects) or evidence of ischemic heart disease (given the risk of proarrhythmia). (See "Major side effects of class I antiarrhythmic drugs".) SPECIFIC ARRHYTHMIAS Atrial fibrillation and flutter The preceding discussion has emphasized the symptoms (eg, palpitations, dyspnea, chest pain and syncope) and life-threatening potential of an arrhythmia itself. Atrial fibrillation (AF) and flutter are associated with additional therapeutic issues, each of which must be addressed. Reversion to sinus rhythm Maintenance of sinus rhythm Slowing the ventricular rate in persistent or permanent atrial fibrillation Prevention of systemic embolization and stroke, both at the time of reversion and in patients chronically These issues are discussed in detail separately. (See "Atrial fibrillation: Overview and management of new-onset atrial fibrillation".) Premature atrial complex A PAC is the early activation of the atria arising from a site other than the sinus node. PACs are observed on the surface ECG as a P wave that occurs relatively early in the cardiac cycle (ie, prematurely before the next sinus P wave should occur) and has a different morphology from the sinus P wave. Often the PR interval is different from that during https://www.uptodate.com/contents/arrhythmia-management-for-the-primary-care-clinician/print 11/34 7/6/23, 2:50 PM Arrhythmia management for the primary care clinician - UpToDate sinus rhythm; it may be longer or shorter, depending upon the site of origin of the PAC. (See "ECG tutorial: Atrial and atrioventricular nodal (supraventricular) arrhythmias".) PACs may be asymptomatic or cause symptoms such as a sensation of "skipping" or palpitations. PACs are often single and isolated, but may be frequent and may occur in a bigeminal (every other beat) or other repeated pattern. A trigger/stimulant is often identified and its removal may eliminate or significantly reduce symptoms. Antiarrhythmic drug therapy, aside from beta blockers, is rarely recommended. (See "Supraventricular premature beats".) PACs may be blocked in the AV conducting system. This is not necessarily pathologic, and it needs to be differentiated from AV block. Ventricular premature beats Ventricular premature beats (VPBs) are common in the general population and often cause patients to seek medical attention. This includes patients without structural heart disease and those with any form of cardiac disease, independent of severity. The evaluation and management of VPBs is discussed elsewhere. (See "Premature ventricular complexes: Clinical presentation and diagnostic evaluation".) ARRHYTHMIA IN ATHLETES Arrhythmias are not infrequently documented in athletes and can be a source of morbidity and mortality, particularly ventricular tachyarrhythmia and sudden cardiac arrest. They can be a reason to consider restriction from athletics. (See "Overview of sudden cardiac arrest and sudden cardiac death".) The evaluation and management of arrhythmia in athletes is discussed separately. (See "Athletes with arrhythmias: Clinical manifestations and diagnostic evaluation" and "Athletes with arrhythmias: Treatment and returning to athletic participation".) INFORMATION FOR PATIENTS UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." th th The Basics patient education pieces are written in plain language, at the 5 to 6 grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more th th sophisticated, and more detailed. These articles are written at the 10 to 12 grade reading https://www.uptodate.com/contents/arrhythmia-management-for-the-primary-care-clinician/print 12/34 7/6/23, 2:50 PM Arrhythmia management for the primary care clinician - UpToDate level and are best for patients who want in-depth information and are comfortable with some medical jargon. Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.) Basics topic (see "Patient education: Ventricular premature beats (The Basics)") SUMMARY AND RECOMMENDATIONS An arrhythmia is any rhythm that is not normal sinus rhythm with normal atrioventricular (AV) conduction. During sinus rhythm, the heart rate is in the normal range, the P waves are normal on the electrocardiogram (ECG), the AV conduction is normal, and the rate is stable. (See 'Definition' above.) When the primary care clinician (PCC) first encounters a patient with an arrhythmia, the following questions should be addressed (see 'Approach to the patient' above): Is the arrhythmia causing symptoms or could it? Does the arrhythmia pose a risk to the patient? Does the arrhythmia require emergent cardioversion? Which arrhythmia is present? Does the patient require urgent hospitalization? Is specialist consultation required, and if so, how urgently? Should anticoagulation and/or other medical therapy be started? For patients who are symptomatic in the office, the management strategy will depend both on the characteristics of the symptoms and the type of arrhythmia present. In the following clinical scenarios, we recommend urgent transfer to a facility with emergency care capabilities (see 'Patients identified with an arrhythmia' above): Syncope or near syncope in patients with high degree AV block (ie, Mobitz type II second degree or third degree [complete] AV block) or bradycardia. Wide complex rhythms (other than sinus with bundle branch block) including ventricular tachycardia. https://www.uptodate.com/contents/arrhythmia-management-for-the-primary-care-clinician/print 13/34 7/6/23, 2:50 PM Arrhythmia management for the primary care clinician - UpToDate Patients in whom the diagnosis is uncertain after examination and ECG, but for whom there is a concern about a life-threatening arrhythmia. Patients with a history of heart disease (including coronary artery disease, cardiomyopathy, or heart failure) who present with syncope, near syncope, and/or documented ventricular arrhythmia. Sustained supraventricular tachycardia (SVT). Atrial fibrillation or flutter with rapid or slow rates. All antiarrhythmic drugs have the potential to increase ectopy or induce or aggravate monomorphic VT, torsades de pointes, ventricular fibrillation (VF), conduction disturbances, or bradycardia; this known as proarrhythmia ( table 3). We suggest the involvement of a specialist (cardiologist or electrophysiologist) when initiation of an antiarrhythmic drug is considered. (See 'Initiation of therapy' above.) The role of the PCC in the long-term care of patients with arrhythmias depends upon the particular arrhythmia diagnosis and treatment. All patients should be queried at each routine visit about changes in symptoms relevant to the arrhythmia and its treatment. ACKNOWLEDGMENT The UpToDate editorial staff acknowledges Leonard Ganz, MD, FHRS, FACC, who contributed to an earlier version of this topic review. Use of UpToDate is subject to the Terms of Use. REFERENCES 1. Shen WK, Sheldon RS, Benditt DG, et al. 2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines, and the Heart Rhythm Society. J Am Coll Cardiol 2017. 2. Zimetbaum PJ, Josephson ME. The evolving role of ambulatory arrhythmia monitoring in general clinical practice. Ann Intern Med 1999; 130:848. Topic 961 Version 26.0 https://www.uptodate.com/contents/arrhythmia-management-for-the-primary-care-clinician/print 14/34 7/6/23, 2:50 PM Arrhythmia management for the primary care clinician - UpToDate GRAPHICS Classification of cardiac arrhythmias Supraventricular Atrial origin Atrial fibrillation Atrial flutter Atrial tachycardia Ectopic focus (enhanced automaticity) Intraatrial or sinoatrial reentry Atrial extrasystoles (atrial premature beats) AV junction Atrioventricular nodal reentrant tachycardia Atrioventricular reentrant tachycardia AV junctional rhythms (enhanced automaticity) AV junctional extrasystoles Ventricular Ventricular tachycardia Sustained Nonsustained Ventricular fibrillation Ventricular extrasystoles (ventricular premature beats) Graphic 72601 Version 1.0 https://www.uptodate.com/contents/arrhythmia-management-for-the-primary-care-clinician/print 15/34 7/6/23, 2:50 PM Arrhythmia management for the primary care clinician - UpToDate ECG of polymorphic ventricular premature beats The ambulatory monitoring tracing demonstrates ventricular premature beats with 3 different morphologies, known as polymorphic ventricular premature beats; 1 ventricular couplet (2 successive premature beats) is also seen (arrow). The blocked P waves after the first and second premature beats (*) are due to concealed retrograde AV nodal conduction from the premature beat. ECG: electrocardiogram; VPBs: ventricular premature beats; AV: atrioventricular. Reproduced with permission by Samuel Levy, MD. Graphic 74977 Version 4.0 https://www.uptodate.com/contents/arrhythmia-management-for-the-primary-care-clinician/print 16/34 7/6/23, 2:50 PM Arrhythmia management for the primary care clinician - UpToDate ECG of sinus node dysfunction The continuous lead V2 rhythm strip shows evidence of sinus node dysfunction. Following the third sinus beat (*) there is a pause followed by the occurrence of an escape junctional rhythm at a slower rate. P waves reappear (arrows), which are initially dissociated from the QRS complex, but ultimately they become associated with the QRS, resulting in 1:1 conduction. Reproduced with permission by Samuel Levy, MD. Graphic 78649 Version 3.0 https://www.uptodate.com/contents/arrhythmia-management-for-the-primary-care-clinician/print 17/34 7/6/23, 2:50 PM Arrhythmia management for the primary care clinician - UpToDate Causes of bradycardia Intrinsic Extrinsic Idiopathic degenerative disorder Drugs Ischemic heart disease Antiarrhythmic agents Chronic ischemia Class IA - quinidine, procainamide Acute myocardial infarction Class IC - propafenone, flecainide Hypertensive heart disease Class II - -blockers Cardiomyopathy Class III - sotalol, amiodarone, dronedarone Trauma Class IV - diltiazem, verapamil Surgery for congenital heart disease Cardiac glycosides Heart transplant Antihypertensive agents Inflammation Clonidine, reserpine, methyldopa Collagen vascular disease Antipsychotic agents Rheumatic fever Lithium, phenothiazines, amitriptyline Pericarditis Autonomically mediated Infection Vasovagal syncope (cardioinhibitory) Viral myocarditis Carotid sinus hypersensitivity Lyme disease (Borrelia burgdorfer I) Hypothyroidism Neuromuscular disorder Intracranial hypertension Friedreich ataxia Hypothermia X-linked muscular dystrophy Hyperkalemia Familial disorder Hypoxia Anorexia nervosa Reproduced with permission from: Fuster V, Walsh R, Harrington R. Hurst's the Heart, 13th ed, McGraw-Hill Professional, New York 2010. Copyright 2010 The McGraw-Hill Companies, Inc. Graphic 65521 Version 11.0 https://www.uptodate.com/contents/arrhythmia-management-for-the-primary-care-clinician/print 18/34 7/6/23, 2:50 PM Arrhythmia management for the primary care clinician - UpToDate ECG of sustained monomorphic ventricular tachycardia Shown are the six precordial electrocardiogram (ECG) leads (V1-V6). The QRS complex is wide and bizarre and the rhythm is ventricular tachycardia (VT). The sixth (+) and seventh (*) QRS complexes show a change in morphology, resembling a normal QRS complex; these represent fusion beats, with partial (+) or complete (*) normalization of the QRS complex. The seventh QRS complex (*) is preceded by a distinct P wave, which is probably conducted, capturing the ventricle for one beat, but not terminating the VT; this is also known as a Dressler beat. Reproduced with permission by Samuel Levy, MD. Graphic 69201 Version 3.0 https://www.uptodate.com/contents/arrhythmia-management-for-the-primary-care-clinician/print 19/34 7/6/23, 2:50 PM Arrhythmia management for the primary care clinician - UpToDate Sustained ventricular tachycardia on ambulatory monitoring The ambulatory monitor in a patient being evaluated for syncope, which persisted after pacemaker insertion, shows sustained monomorphic ventricular tachycardia