ACC-AHA 2017 2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death
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| 頁 | クラス | レベル | 推奨文 | 表 |
|---|---|---|---|---|
| p.13 | I | B-NR | Downloaded from http://ahajournals.org by on October 7, 2026 Delayed afterdepolarizations occur after complete membrane repolarization and develop under conditions of intracellular calcium overload. Factors contributing to elevated intracellular calcium load include tachycardia, catecholamines, hypokalemia, digoxin toxicity, cardiac hypertrophy, and HF.S3.4-6,S3.4-7 Elevated sarcoplasmic calcium content or increased sensitivity of the ryanodine receptor can initiate spontaneous calcium release, which activates a transient inward current driven predominantly by the sodium–calcium exchange current. If the membrane depolarization is sufficiently large, the inward sodium current is activated resulting in a triggered action potential. Delayed afterdepolarizations are the underlying mechanism for VT in the setting of digoxin toxicity, catecholaminergic polymorphic VT, and idiopathic outflow tract VA. Delayed afterdepolarizations are also considered to be an important trigger of VA in the setting of HF. Purkinje cells are more susceptible to spontaneous sarcoplasmic reticulum calcium release than ventricular myocytes suggesting that delayed afterdepolarizations may be an important mechanism for some Purkinje fiber-related VA.S3.4-3,S3.4-8,S3.4-9 3.4 Reentry | |
| p.16 | I | B-NR | 1,S4.2.2-4 Serial evaluations with exercise testing and/ or 24-hour ambulatory monitoring are also used to assess rhythm burden and response of VA to therapy. Notably, implantable monitors are covered in Section 4.2.3. Importantly, when the suspicion of VA in a patient is high, outpatient ambulatory monitoring is inappropriate as prompt diagnosis and prevention of VA are warranted. It is important to accurately correlate the symptoms with the arrhythmias detected by ambulatory ECG monitoring. | |
| p.16 | IIa | C-EO | 4.2.3 Implanted Cardiac Monitors Recommendation for Implanted Cardiac Monitors Referenced studies that support the recommendation are summarized in Online Data Supplement 5. COR LOE Recommendation 1. In patients with sporadic symptoms (including syncope) suspected to be related to VA, implanted cardiac monitors can be useful.S4.2.3-1–S4.2.3-4 | |
| p.17 | I | C-EO | disease is required in patients with or at high risk for VA or SCD, including patients with cardiomyopathy, HF, prior MI, family history of cardiomyopathy or SCD, or an inherited structural heart disease associated with SCD. Echocardiography is the most readily available and commonly used imaging technique.S4.2.4-1,S4.2.4-2 LVEF is a strong, independent predictor of SCD and cardiovascular mortality and a determinant of eligibility for ICD implantation for primary prevention of SCD.S4.2.4-1 In SCD-HeFT (the Sudden Cardiac Death in Heart Failure Trial),S4.2.4-2 the benefit of the ICD was not dependent on the modality (ie, echocardiography, radionuclide angiography, or contrast angiograms) by which the LVEF was assessed. In clinical practice, if cardiac CTS4.2.4-3 or cardiac MRI has been performed and provides sufficient evaluation, echocardiography may be unnecessary. This recommendation for imaging differs from that of the 2017 ACC/AHA/HRS syncope guidelineS4.2.4-4 that applies to patients who may not have VA. 2. VA or SCA can be an initial manifestation of ischemic heart disease, cardiomyopathic processes, or myocarditis. Cardiac CT and cardiac MRI allow for evaluation of structural heart disease and assessment of LV and RV function including quantification of LVEF, LV mass and volume, valvular structure and coronary anatomy including anomalous coronary origins. Cardiac MRI can be useful in the evaluation for myocardial scar and infiltrative processes evident as late gadolinium enhancement.S4.2.4-5–S4.2.4-9 Cardiac MRI also provides high-quality assessment of LV and RV function, size, and degree of fibrosis and is particularly useful in arrhythmogenic right ventricular cardiomyopathy and HCM. Downloaded from http://ahajournals.org by on October 7, 2026 4.2.5 Biomarkers Recommendation for Biomarkers | |
| p.18 | IIa | B-R | Downloaded from http://ahajournals.org by on October 7, 2026 Recommendation-Specific Supportive Text 1. The decision to proceed with genetic testing requires discussion regarding the clinical use of genetic information to be obtained for both the proband and family members, as well as consideration of the important psychological, financial, employment, disability, and life insurance implications of positive genotyping.S4.2.6-17,S4.2.6-18,S4.2.6-20,S4.2.6-24 Balancing privacy of health care information for the proband with the “right to know” for family members, and the ability to provide appropriate communication of information to all potentially affected family members can be challenging on many levels, including family dynamics, geographic proximity, and access to health care.S4.2.6-25 For these reasons, genetic counseling generally occurs before proceeding with genetic testing, and, from a patient’s perspective, is optimally provided by genetic counselors, if available, in collaboration with physicians.S4.2.6-26,S4.2.6-27 A combined approach of genetic counseling with medical guidance may appropriately balance the decision as to whether genetic testing would be beneficial on an individual basis. | |
| p.24 | I | A | Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.25 | I | B-NR | 5.4.2. VA in Patients With No Apparent Structural Heart Disease See Section 8. CLINICAL STATEMENTS AND GUIDELINES | |
| p.25 | I | C-EO | VA that are not associated with underlying structural heart disease or a genetic arrhythmia syndrome are commonly referred to as idiopathic. Most idiopathic VA are monomorphic and based on a focal mechanism of triggered activity or abnormal automaticity; a few are due to reentry. For patients who are symptomatic, and in whom antiarrhythmic medications are ineffective, not tolerated, or not desired by the patient, catheter ablation is a treatment option. The ablation strategy is to identify the site of origin manifested by the earliest site of electrical activation, or when this is not practical, by pace mapping. Catheter ablation of idiopathic VA is usually accomplished with endocardial catheterization, though an epicardial approach through the coronary venous circulation or a subxiphoid pericardial puncture may occasionally be required. Ablation failure for idiopathic VA is often due to inability to provoke the arrhythmia to allow mapping in the electrophysiological laboratory or origin from an inaccessible region. 5.4.3 Scar-Related VT See Section 8. | |
| p.26 | I | A | 5.6 Autonomic Modulation Recommendations for Autonomic Modulation References that support the recommendations are summarized in Online Data Supplements 13 and 14. COR LOE Recommendations 1. In patients with symptomatic, non–lifethreatening VA, treatment with a beta blocker is reasonable.S5.6-1 2. In patients with VT/VF storm in whom a beta blocker, other antiarrhythmic medications, and catheter ablation are ineffective, not tolerated, or not possible, cardiac sympathetic denervation may be reasonable.S5.6-2–S5.6-4 | |
| p.26 | I | A | Synopsis Sympathetic activation is proarrhythmic and parasympathetic activation is generally antiarrhythmic in VT/VF. | |
| p.27 | I | A | CLINICAL STATEMENTS AND GUIDELINES | |
| p.27 | IIb | B-R | Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.31 | I | B-NR | 1. In the AVID trial,S7.1.1-1 the ICD improved overall survival compared with antiarrhythmic medication therapy (primarily amiodarone) in patients who survived SCD or with hemodynamically unstable VT, with a 2-year relative risk reduction in mortality of 27% and an absolute risk reduction of 7%. CIDS (Canadian Implantable Defibrillator Study),S7.1.1-2 which was stopped early after the results of the AVID trial were released, showed a similar, but not statistically significant, benefit of the ICD over antiarrhythmic medication therapy. A subsequent meta-analysis using data from 3 RCTs showed a statistically significant reduction in both arrhythmic and all-cause mortality with secondary prevention ICDs.S7.1.1-3 | |
| p.31 | IIa | B-NR | In survivors of life-threatening VA that may be due to transient or reversible factors, such as AMI, proarrhythmic medication effects, or electrolyte disturbances, an ICD is not implanted if the cause may be correctable. This is a population of patients that still requires thorough evaluation, treatment, and close follow-up and, as in the AVID registry, mortality was still high in the population that may have had a reversible cause for their arrest.S7.1.1-8 Small increases in troponin present a challenge in selecting patients for an ICD, as it often cannot be determined whether troponin elevation is due to ischemia from VT/VF and resuscitation, in which | |
| p.32 | I | A | 2. Patients with coronary artery spasm who survive an SCA are a high-risk population.S7.1.1.1-5 Recurrent VA, even life-threatening, may be prevented if coronary artery spasm can be effectively addressed with risk factor modification, smoking cessation, and ongoing treatment with nitrates and dihydropyridine calcium channel blockers.S7.1.1.1-9 However, SCA or VA can recur despite medical therapy or if compliance is poor. Whether a wearable cardioverter-defibrillator may provide protection while medical therapy is being evaluated has not been assessed but is of interest.S7.1.1.1-10 An ICD can terminate VT/VF initiated by spasm, potentially preventing SCD. 3. Patients with coronary vasospasm who survive an SCA are a high-risk population, and some support the use of an ICD in those patients based on the reported event rates from observational studiesS7.1.1.1-5 even before determining the patient’s response to or compliance with medical therapy. Recurrent SCA can occur despite medical therapy. Regardless of the approach, risk factor modification (eg, illicit drug use), smoking cessation, and ongoing treatment with dihydropyridine calcium channel blockers with or without nitrates represent essential treatments.S7.1.1.1-9 Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.32 | I | A | 7.1.1.2. Post CABG VT/VF The incidence of sustained VT or VF early after CABG is low, but these VAs are associated with high in-hospital mortality.S7.1.1.2-1 VF occurring very early (intraoperatively or within 24 hours postoperatively) may be due to the transient effects of reperfusion, electrolyte and acid base disturbances, and the use of inotropes. Patients who present with VF or polymorphic VT in the postoperative period more often have associated ischemia, while patients presenting with monomorphic VT usually have an old infarct and ventricular scar.S7.1.1.2-2 Polymorphic VT/VF occurring after CABG warrants a therapeutic approach targeting treatment of myocardial ischemia, including a possible need for assessment of graft patency, as well as identification and treatment of mechanical complications and acute electrolyte or acid base disturbances. Risk factors for occurrence of monomorphic VT early af- | |
| p.33 | IIa | B-NR | CLINICAL STATEMENTS AND GUIDELINES | |
| p.34 | I | B-R | Downloaded from http://ahajournals.org by on October 7, 2026 5. In a retrospective analysis of the UNOS (United Network for Organ Sharing) registry that extended from 1999 to 2014, data on 32 599 patients showed that during a median follow-up of 154 days, 3638 patients (11%) died while on the waitlist for cardiac transplantation (9% in the ICD group versus 15% in the non-ICD group; P<0.0001). The presence of an ICD at listing was associated with an adjusted 13% relative risk reduction in mortality. In the subgroup of patients with an LVAD (n=9478), an ICD was associated with an adjusted 19% relative risk reduction in mortality.S7.1.2-9 In another study of 380 patients listed for heart transplantation between 2005 and 2009 at 1 tertiary heart transplant center, 122 patients received an ICD before or within 3 months after being listed for heart transplantation. Non-ICD patients were more likely to die while on the transplant list. In a multivariable model, the ICD was not associated with improved survival; however, that analysis was limited by the small sample size.S7.1.2-8 Another small study (n=79) conducted at 1 institution suggested | |
| p.37 | I | B-NR | CLINICAL STATEMENTS AND GUIDELINES | |
| p.37 | IIa | C-EO | Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.37 | IIa | B-NR | 7.2 Nonischemic Cardiomyopathy Recommendations for Patients With NICM References that support the recommendations are summarized in Online Data Supplement 24. COR LOE Recommendations 1. In patients with suspected NICM from myocardial infiltrative processes, cardiac MRI with late gadolinium enhancement is useful for diagnosis.S7.2-1–S7.2-3 2. In patients with suspected NICM, cardiac MRI with late gadolinium enhancement can be useful for assessing risk of SCA/SCD.S7.2-1–S7.2-3 | |
| p.37 | IIb | B-R | 3. In patients with NICM who develop conduction disease or LV dysfunction at less than 40 years of age, or who have a family history of NICM or SCD in a first-degree relative (<50 years of age), genetic counseling and genetic testing are reasonable to detect a heritable disease that may clarify prognosis and facilitate cascade screening of relatives.S7.2-4,S7.2-5 Recommendation-Specific Supportive Text 1. Cardiac MRI allows for evaluation of structural heart disease and assessment of LV and RV function including quantification of LVEF, LV mass and volume, and valvular structure. Cardiac MRI can help in the evaluation for myocardial infiltrative processes and evidence of scar, indicated by delayed hyperenhancement, associated with VA.S7.2-1–S7.2-4,S7.2-6 | |
| p.38 | IIb | B-R | 2. Small observational studies demonstrated high mortality and frequent appropriate ICD shocks in patients with syncope and NICM.S7.2.1-7–S7.2.1-9 The assumption that malignant VAs are the likely cause of syncope and that the ICD would be protective has recently been challenged. In a subgroup analysis of SCD-HeFT that included 472 patients, the ICD did not reduce either recurrent syncope or the increased risk of mortality associated with syncope.S7.2.1-10 A subgroup analysis of the MADIT-RIT (Multicenter Automatic Defibrillator Implantation Trial-Reduce Inappropriate Therapy) trial found syncope to be arrhythmic only in 39% of patients.S7.2.1-11 These studies suggest that syncope in some HF patients may be an indicator of an end-stage cardiomyopathy associated with a poor prognosis.S7.2.1-11 In a substudy of DEFINITE, inducible sustained VT/VF was found in a minority of patients, but it was associated with appropriate ICD therapy.S7.2.1-14 Another study of electrophysiological testing in NICM found inducible VT/VF in 27.8% of patients, which was associated with future ICD events.S7.2.1-15 In a study of patients with NICM, cardiac mortality correlated with LVEF but not with inducibility on electrophysiological study.S7.2.1-16 Based on these data, many experts are uncomfortable withholding an ICD from patients with NICM who experience syncope potentially due to a VA even if the electrophysiological study shows no inducible sustained VT. 3. Access to ICDs may be limited by financial, medical, or personal considerations. In addition, not all patients at high risk of SCD meet ICD indications, such as those with class IV HF without CRT possibility or with a life expectancy <1 year. A meta-analysis of RCTs, which examined the use of amiodarone for the prevention of SCD, included 15 studies with 8522 patients assigned to amiodarone or placebo/control.S7.2.1-12 Amiodarone reduced the risk of SCD by 29%; however, it did not reduce all-cause mortality and was associated with an increased risk of pulmonary and thyroid toxicity. In a subgroup analysis, the benefit of amiodarone appeared similar in patients with ischemic cardiomyopathy and those with NICM.S7.2.1-12 In a separate meta-analysis,S7.2.1-13 the evidence was insufficent to support amiodarone’s efficacy for reduction of SCD and all-cause mortality in survivors of cardiac arrest or those with syncope due to VA. A subgroup analysis of the VALIANT (Valsartan in Acute Myocardial Infarction) trial found that amiodarone was associated with increased mortality in patients with NYHA class III HF.S7.2.1-17 These data call for a careful and nuanced approach to using amiodarone Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.39 | IIa | B-R | therapy arms. Therefore, the results of DANISH should not be generalized to patients with NICM who are ineligible for CRT. During a median follow-up of 5.6 years, ICD reduced SCD from 8.4% to 4.3%, but there was no difference in all-cause mortality.S7.2.2-11 Several meta-analyses have been published.S7.2.2-12,S7.2.2-13 One provided data on ICDs with and without CRT and showed survival benefit from the ICD.S7.2.2-13 The second used patient level data from 2 trials and adopted a more robust approach to reducing heterogeneity by excluding patients with CRT and those randomized to antiarrhythmic medications; a 25% relative risk reduction in mortality with an ICD was shown.S7.2.2-12 CLINICAL STATEMENTS AND GUIDELINES | |
| p.39 | IIa | B-NR | Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.40 | I | B-NR | Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.40 | I | B-NR | subendocardial, subepicardial, or intramyocardial, and all locations may be affected and require endocardial and epicardial ablation. In the HELP-VT (Heart Center of Leipzig VT) study,S7.2.3-2 successful ablation of all VT morphologies was achieved in 66.7% of patients with NICM, compared with the 77.4% success rate in ischemic cardiomyopathy. An epicardial approach to ablation was required in 30.2% of NICM patients, compared with only 1.2% with ischemic cardiomyopathy. Epicardial ablation was an independent predictor of successful ablation. Acute and long-term success of ablation is lower for NICM, compared with post-MI patients. The long-term survival-free of VT recurrence after catheter ablation appears to be better for patients with ischemic than NICM (57% versus 40.5% at 1 year).S7.2.3-2 Risks are similar to those observed for post-MI VT ablation, with additional risks of epicardial access and ablation when required. Although any NICM can produce scar-related VT, cardiac sarcoidosis (see Section 7.6) and Lamin mutations are particularly associated with sustained monomorphic VT.S7.2.3-6 | |
| p.41 | I | B-NR | CLINICAL STATEMENTS AND GUIDELINES | |
| p.41 | IIa | B-NR | Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.44 | IIa | B-NR | Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.47 | IIb | C-LD | Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.47 | I | B-NR | 2. In patients with giant cell myocarditis with VF or hemodynamically unstable VT treated according to GDMT, an ICD and/or an antiarrhythmic medication may be considered if meaningful survival of greater than 1 year is expected.S7.5-2–S7.5-4 Recommendation-Specific Supportive Text | |
| p.47 | IIa | C-LD | 1. Myocarditis is an inflammatory process often related to infection.S7.5-1,S7.5-5–S7.5-9 When patients are treated in centers with the availability of mechanical hemodynamic support procedures, cardiac catheterization, endomyocardial biopsy, advanced cardiac imaging procedures, and arrhythmia management including ICD implantation, outcomes appear improved.S7.5-1 The acute course of myocarditis varies ranging from an asymptomatic finding of transient ST-T changes noted on ECG to cardiogenic shock and recurrent VA.S7.5-10–S7.5-12 Acute management is largely supportive and can rapidly advance to requiring mechanical support.S7.5-13,S7.5-14 Cardiac arrhythmias range from conduction abnormalities to life-threatening VT and VF.S7.5-15–S7.5-17 Arrhythmias may require antiarrhythmic medications and/or device therapy.S7.5-18 Giant cell myocarditis is fairly uncommon, but it is of particular importance because it typically affects young individuals and is usually fatal if untreated.S7.5-2–S7.5-4,S7.5-19 VT may require antiarrhythmic medications such as amiodarone and/ or an ICD that in some instances can be used as a bridge to more advanced HF therapies | |
| p.50 | IIa | B-NR | Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.51 | I | B-NR | 1. Patients with an LVAD have a high risk of VA, particularly those with a history of arrhythmias.S7.7.3-2–S7.7.3-4 The increased risk of VA may be due to myocardial irritation from insertion of the LVAD inflow cannula, LV compression due to a suctioning effect from the LVAD, inotropic support frequently needed by some patients, and repolarization changes that can occur after LVAD placement. Although VT/VF is tolerated by some patients with an LVAD, others experience a decrease in flow as the RV is unsupported; syncope and hypoperfusion can result. Having an ICD can allow for prompt termination of VA before significant hemodynamic consequences occur. Data on ICDs in patients with an LVAD are from observational series. A systematic review of 6 observational studies observed that within 7 months, 26% of patients with an LVAD had died.S7.7.3-1 The death rate was lower among patients who previously had an ICD (16% versus 32%), suggesting a 39% relative-risk reduction in all-cause mortality in an adjusted analysis.S7.7.3-1 Patients with a history of pre-LVAD VA have nearly a ≥10-fold risk of post-LVAD VA.S7.7.3-2–S7.7.3-4 In many of the initial studies demonstrating ICD benefit, older pulsatile LVAD devices were in use.S7.7.3-2,S7.7.3-5 Studies of ICD use with the newer, continuous flow LVADs have inconsistently shown benefit.S7.7.3-1,S7.7.3- Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.51 | IIb | B-NR | 4,S7.7.3-6,S7.7.3-7 Of note, approximately 2 of 10 patients with an LVAD develop an LVAD related infection in the first year.S7.7.3-8,S7.7.3-9 7.7.4 ICD Use After Heart Transplantation Recommendation for ICD Use After Heart Transplantation References that support the recommendation are summarized in Online Data Supplement 37. COR LOE Recommendation 1. In patients with a heart transplant and severe allograft vasculopathy with LV dysfunction, an ICD may be reasonable if meaningful survival of greater than 1 year is expected.S7.7.4-1–S7.7.4-3 Recommendation-Specific Supportive Text | |
| p.53 | I | B-NR | Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.54 | I | B-NR | Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.58 | IIa | B-NR | Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.59 | I | B-NR | Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.59 | IIb | C-EO | 7.9.1.3 Brugada Syndrome Recommendations for Brugada Syndrome References that support the recommendations are summarized in Online Data Supplement 42 and Systematic Review Report. COR LOE Recommendations 1. In asymptomatic patients with only inducible type 1 Brugada electrocardiographic pattern, observation without therapy is recommended.S7.9.1.3-1–S7.9.1.3-5 2. In patients with Brugada syndrome with spontaneous type 1 Brugada electrocardiographic pattern and cardiac arrest, sustained VA or a recent history of syncope presumed due to VA, an ICD is recommended if meaningful survival of greater than 1 year is expected.S7.9.1.3-4,S7.9.1.3-6 3. In patients with Brugada syndrome experiencing recurrent ICD shocks for polymorphic VT, intensification of therapy with quinidine or catheter ablation is recommended.S7.9.1.3-7–S7.9.1.3-11 4. In patients with spontaneous type 1 Brugada electrocardiographic pattern and symptomatic VA who either are not candidates for or decline an ICD, quinidine or catheter ablation is recommended.S7.9.1.3-7,S7.9.1.3-9–S7.9.1.3-11 | |
| p.62 | I | B-NR | 7.9.1.4. Early Repolarization “J-wave” Syndrome Recommendations for Early Repolarization Syndrome References that support the recommendations are summarized in Online Data Supplement 43. COR LOE Recommendations | |
| p.62 | IIa | C-LD | 1. In asymptomatic patients with an early repolarization pattern on ECG, observation without treatment is recommended.S7.9.1.4-1,S7.9.1.4-2 | |
| p.62 | IIa | C-LD | 2. In patients with early repolarization pattern on ECG and cardiac arrest or sustained VA, an ICD is recommended if meaningful survival greater than 1 year is expected.S7.9.1.4-3,S7.9.1.4-4 | |
| p.62 | IIb | C-EO | 3. In patients with early repolarization pattern on ECG, genetic testing is not recommended.S7.9.1.4-5 III: No Benefit B-NR Recommendation-Specific Supportive Text | |
| p.63 | I | B-R | CLINICAL STATEMENTS AND GUIDELINES | |
| p.63 | IIa | B-R | Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.63 | I | B-NR | Most idiopathic VA are due to a focal mechanism of triggered activity or abnormal automaticity, some, notably interfascicular reentrant LV tachycardias, are due to reentry. The clinical manifestations of idiopathic VA are highly variable and range from benign, asymptomatic PVCs to sustained VT or even VF. On initial discovery, an evaluation for structural heart disease is warranted with physical examination, an ECG, and imaging, usually with echocardiography. In the absence of any abnormality or a family history of SCD, further assessment and treatment are guided by symptoms. If the patient is asymptomatic and does not have evidence of a cardiac channelopathy, reassurance as to the benign nature is sufficient. If the arrhythmia is suspected of being sufficiently frequent to cause ventricular dysfunction over time, periodic follow-up with reassessment of ventricular function is warranted (see Section 10.8). For mild symptoms, avoidance of aggravating factors such as excessive consumption of caffeine or sympathomimetic agents, may be sufficient. Therapy with a beta blocker or nondihydropyradine calcium channel blocker reduces symptoms for some patients. Class I antiarrhythmic medications can be effective, but those are generally avoided due to concerns for adverse effects. For patients who require arrhythmia suppression for whom antiarrhythmic medications are ineffective, not tolerated, or undesired, catheter ablation can be a highly effective treatment (see Section 9). The ablation strategy is to identify the site of | |
| p.64 | I | B-NR | Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.64 | IIa | C-LD | 8.2 Papillary Muscle VA Recommendation for Papillary Muscle VA (PVCs and VT) References that support the recommendation are summarized in Online Data Supplement 47. COR LOE Recommendation 1. In patients with symptomatic VA arising from the papillary muscles for whom antiarrhythmic medications are ineffective, not tolerated, or not the patient’s preference, catheter ablation is useful.S8.2-1–S8.2-5 | |
| p.65 | I | B-NR | CLINICAL STATEMENTS AND GUIDELINES | |
| p.65 | I | B-NR | sensitive.S8.3-1–S8.3-3 These VTs are typically sustained with a QRS that has a right bundle-branch block configuration with a superior axis. Less frequently an inferior axis VT or a relatively narrow QRS VT occurs as a result of alternate reentry paths, also involving a part of the Purkinje system. Beta blockers or verapamil typically terminate these arrhythmias, but they fail to prevent recurrences in some patients.S8.3-1–S8.3-3 The target of catheter ablation for the most common form is usually the distal insertion of the anterograde limb of the Purkinje system along the inferior portion of the LV septum near its junction with the left posterior fascicle. Catheter ablation is acutely successful in >90% of patients with a risk of recurrence of approximately 10%. This VT may resemble fascicular VA that are due to a focal mechanism in the left anterior or left posterior fascicles of the LV His-Purkinje system. These fascicular arrhythmias usually have a focal mechanism with the target of catheter ablation being the site of earliest electrical activation recorded with a presystolic fascicular potential. Catheter ablation is highly effective for intrafascicular and fascicular VA. Serious complications are infrequent and include bleeding at the site of arterial or venous access and a small risk of bundle branch block or atrioventricular block. 2. Idiopathic LVT is based on reentrant mechanism involving tissue with slow conduction properties along the LV septum as the anterograde limb and the normal left posterior fascicle of the His- Purkinje system as the retrograde limb. The slow conduction zone is verapamil-sensitive.S8.3-3–S8.3-6 These arrhythmias typically have a right bundlebranch block morphology with superior axis, though reversal of the circuit may produce a relatively narrow QRS during VT. Verapamil typically terminates these arrhythmias in the anterograde slow conduction zone.S8.3-3–S8.3-6 | |
| p.66 | I | B-NR | a very high risk of recurrent VF, an ICD is indicated to prevent SCD. Catheter ablation of the triggering focus has proved to be highly effective in eliminating the repetitive PVCs which induce VF in these patients.S8.4-11 During a median postprocedural follow-up of 63 months, 7 (18%) of 38 patients undergoing catheter ablation of idiopathic VF induced by short coupled PVCs experienced VF recurrence at a median follow-up of 4 months. Five of these 7 patients underwent repeat ablation without VF recurrence. Thus, although catheter ablation is very effective in idiopathic VF, the recurrence risk remains substantial after an apparently successful procedure and the patient should be protected with an ICD. The subcutaneous ICD may not be a good therapy for these patients due to the higher risk of T-wave oversensing seenin this population; however, data are limited.S8.4-10 | |
| p.66 | IIa | B-NR | Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.67 | I | B-NR | In athletes, VAs range from isolated PVCs, couplets, and NSVT, to sustained VT and SCA leading to SCD.S10.1-1 Infrequent PVCs and short runs of repetitive NSVT, especially in the absence of structural heart disease, are more common in nonathletes, but they are generally benign, requiring only a limited workup and rarely lead to disqualification for sports.S10.1-2,S10.1-3 In contrast, longer runs of NSVT, especially when exercise-induced, and sustained VT and SCA/SCD are infrequent, but they have a higher incidence in athletes than that reported for the general population in the corresponding age groups. Reported estimates of SCD range from 1 per 53 703 athlete-years in the National Collegiate Athletic Association databaseS10.1-4 to <1 per 200 000 in Minnesota high school students.S10.1-5 Among those studies judged to have better epidemiological protocols, estimates were in the range of 1 per 40 000 to 1 per 80 000.S10.1-6 These figures compare with a general population risk of 1.0 to 1.9/100 000 in adolescents and young adults.S10.1-7,S10.1-8 Moreover, there appears to be both sport and sex differences in the magnitude of risk, with males being at higher risk than females in most sports,S10.1-7,S10.1-9 blacks at higher risk than whites, and male basketball players being the single highest risk group in the United States, 1 per 5200 athlete-years.S10.1-4 Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.67 | I | C-EO | A study that included both competitive and recreational athletes showed that both groups are at a higher risk for SCD than the general population, with recreational athletes having greater cumulative numbers,S10.1-7 SCD occurring at an older age, and a different distribution of diseases. Postmortem data on SCD in athletes reveal that 25% to 40% are autopsynegative, suggesting a role for genetic molecular disorders in these victims S10.1-4,S10.1-10,S10.1-11 and for family members.S10.1-12 | |
| p.67 | IIa | B-NR | Another limitation of SCD data analysis in athletes centers on noncardiac causes, some of which mimic cardiac events. Noncardiac causes include acute neurological disorders, drug abuse, heat stroke, rhabdomyolysis, sickle cell disorders, suicides, and | |
| p.70 | I | B-NR | Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.70 | I | C-LD | did not demonstrate any difference between men and women, although total outcomes improved.S10.6-17 | |
| p.70 | IIa | C-LD | The proportion of ischemic heart disease-associated SCAs among women surviving out-of-hospital cardiac arrest was significantly lower than in men, but ischemic heart disease remained the most powerful predictor etiologically,S10.6-18 and women were also significantly less likely to have severe LV dysfunction (LVEF ≤35%) or previously recognized ischemic heart disease.S10.6-19 Women appear to be less likely to benefit from therapeutic hypothermia postcardiac arrest; however, in the younger age group, neurologic recovery in women was better than in older women.S10.6-20 Women are less likely to have SCA during competitive athletic events. A large study including both recreational and competitive athletes across a large age range noted that SCA in women during athletic events was 1 in 20 of that in men.S10.6-21 A large literature review from 1980 to 1992 demonstrated that women accounted for 70% of recorded cases of cardiovascular medication–related arrhythmias.S10.6-22 This is consistent with QT interval differences among men and women. A retrospective analysis of quinidine discontinuation reported a significant difference in discontinuation between men and women (66% versus 84%) largely due to prolonged QT.S10.6-23 A study of catheter ablation for VT reported that overall outcome was similar between men and women.S10.6-24 The only sex difference was the greater probability of women having RVOT VT and a greater probability of men having LV outflow tract VT. | |
| p.71 | I | B-NR | Allelic variants in clinical long QT disease genes have been identified in patients with medicationinduced torsades de pointes.S10.7-7,S10.7-15–S10.7-18 Further, whole exome sequencing implicates an increased burden of rare potassium channel variants in the risk of medication-induced torsades de pointes.S10.7-17,S10.7-19 These findings do not yet support general genetic screening for prediction of medication-induced torsades de pointes. In long QT syndrome, genetic testing may be performed in the index case who experienced medicationinduced torsades de pointes and, if he/she did not survive that event, electrocardiographic screening of first-degree relatives may be performed. 4. Maintaining serum potassium between 4.5 mEq/L and 5 mEq/L shortens QT and may reduce the chance of recurrent torsades de pointes.S10.7-6,S10.7-7 5. In large clinical trials, sodium channel blockers increased mortality among patients convalescing from MI,S10.7-20 but similar trends were also seen with earlier trials of mexiletineS10.7-21 and disopyramide.S10.7-22 Based on CAST, flecainide is contraindicated in patients with ischemia, prior MI, and is avoided in patients with other structural heart diseases.S10.7-20 | |
| p.71 | I | B-NR | Sodium channel blockers increase defibrillation energy requirement and pacing thresholdsS10.7-8,S10.7-9; as a consequence, patients may require reprogramming or revision of pacing or ICD systems or changes in their medication regimens (although modern pacing systems that provide automatic pacing threshold testing and adjustment of pacing output have mitigated the risk of loss of capture). Sodium channel blockers can “convert” AF to slow atrial flutter, which can show 1:1 atrioventricular conduction with wide QRS complexes that can be confused with VT.S10.7-23 | |
| p.72 | IIa | B-NR | Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.76 | I | B-NR | Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.77 | IIa | B-NR | CLINICAL STATEMENTS AND GUIDELINES | |
| p.77 | IIb | B-NR | implantable cardioverter-defibrillator may be preferred in patients who are at high risk of infection, such as those with a prior device infection, ESRD, diabetes mellitus, or who are chronically immunosuppressed. 2. Nonrandomized studies show that the subcutaneous implantable cardioverter-defibrillator reliably detects and converts VF during defibrillation threshold testing and successfully terminates spontaneous sustained VT that occurs during follow-up.S11.1-1,S11.1-13 In 1 study of 314 patients, the 180-day complication-free rate was 99%, and the success of VF termination with first shock was >90%.S11.1-2 All spontaneous episodes of VT/VF recorded in 21 patients (6.7%) were successfully converted, and there were no lead failures, endocarditis or bacteremia, tamponade, cardiac perforation, pneumothorax, or hemothorax associated with the subcutaneous implantable cardioverter-defibrillator.S11.1-2 In 472 patients enrolled in the EFFORTLESS (Evaluation of Factors Impacting Clinical Outcome and Cost Effectiveness of the S-ICD) registry,S11.1-3 the complication-free rate was 94%, at 360 days. First shock conversion efficacy was 88% with 100% overall successful clinical conversion after a maximum of 5 shocks. In 882 patients enrolled in investigational device exemption trials and the EFFORTLESS registry,S11.1-4 111 spontaneous VT/ VF events were treated in 59 patients; 90.1% were terminated with 1 shock, and 98.2% were terminated within the 5 available shocks. The estimated 3-year inappropriate shock rate was 13.1% most due to oversensing of cardiac signals, and mortality was 4.7%. Device-related complications occurred in 11.1% of patients. An ongoing trial will compare the effect of the subcutaneous implantable cardioverter-defibrillator with that of the transvenous ICD on the outcomes of inappropriate shocks, complications, shock efficacy, and mortality.S11.1-13 | |
| p.78 | I | C-LD | the wearable cardioverter-defibrillator may allow the patient to be discharged from the hospital with protection from VT/SCA until the clinical situation allows reimplantation of an ICD. 2. The patients listed in this recommendation are represented in clinical series and registries that demonstrate the safety and effectiveness of the wearable cardioverter-defibrillator. Patients with recent MI, newly diagnosed NICM, recent revascularization, myocarditis, and secondary cardiomyopathy are at increased risk of VT/SCA. However, the wearable cardioverter-defibrillator is of unproven benefit in these settings, in part because the clinical situation may improve with therapy and time. In patients awaiting transplant, even with anticipated survival <1 year without transplant, and depending on clinical factors such as use of intravenous inotropes and ambient VA, a wearable cardioverter-defibrillator may be an alternative to an ICD. | |
| p.78 | IIa | B-NR | Downloaded from http://ahajournals.org by on October 7, 2026 11.3 Automated External Defibrillator | |
| p.79 | I | B-NR | Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.80 | I | C-EO | Downloaded from http://ahajournals.org by on October 7, 2026 | |
| p.80 | I | B-NR | Synopsis A particularly challenging area of medicine is recognizing when life-prolonging therapies may become burdensome or even harmful. This is particularly true near the end of life for patients with ICDs in whom once lifeprolonging shocks may only cause unnecessary morbidity and distress to both patients and loved ones. Recommendation-Specific Supportive Text | |
| p.80 | I | B-NR | 1. Current evidence suggests that many patients are unaware of the possibility that their ICD can be deactivated without surgery.S14-1–S14-3 During decision-making, clinicians do not routinely inform patients about ICD deactivation.S14-4 Clinicians even disagree on whether discussions of deactivation should occur when patients are making a decision about an ICD-related procedure.S14-5 As a result, patients often do not include wishes |