p.32 抽出テキスト

Circulation. 2018;138:e272–e391. DOI: 10.1161/CIR.0000000000000549 September 25, 2018 e303 CLINICAL STATEMENTS AND GUIDELINES

Recommendation-Specific Supportive Text

1.	 Coronary artery spasm results from vasomotor dysfunction and can occur in the presence or absence of atherosclerotic ischemic heart disease. Vasospasm episodes can lead to VA, syncope, and SCD. Treatment includes risk factor elimination including smoking cessation, and treatment with vasodilators including dihydropyridine calcium channel blockers with or without nitrates. A more detailed summary of treatments for coronary artery spasm can be found in other guideline documents.S7.1.1.1-7,S7.1.1.1-8 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 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- ter CABG include prior MI, ventricular scar, LV dysfunction, and placement of a bypass graft across a noncollateralized occluded coronary vessel to a chronic infarct zone.S7.1.1.2-3 Unlike polymorphic VT and VF, sustained monomorphic VT is typically not due to acute ischemia. Many of these patients have inducible sustained VT at electrophysiological study. Management of symptomatic VA in the early period after CABG follows the recommendations for acute and ongoing management of VT detailed elsewhere in this document. In patients without sustained VT or VF but with LV dysfunction prior to undergoing CABG, implantation of an ICD did not improve survival.S7.1.1.2-4 For patients with LV dysfunction who are undergoing revascularization, there is a possibility that the LV function may improve, so many advocate for reassessment of the LV function 3 months after revascularization before a decision about ICD implantation is made.S7.1.1.2-5 For patients with a high burden of NSVT and reduced LVEF, an electrophysiological study may be helpful for risk stratification; those with inducible sustained VT may benefit from an ICD.S7.1.1.2-6 The wearable cardioverter-defibrillator may play a role in patients at risk of SCD in the early phase after revascularization to allow time for recovery of ventricular function.S7.1.1.2-7

7.1.2 Primary Prevention of SCD in Patients With Ischemic Heart Disease

Recommendations for Primary Prevention of SCD in Patients With Ischemic Heart Disease References that support the recommendations are summarized in Online Data Supplement 21.

COR LOE Recommendations

I A 1. In patients with LVEF of 35% or less that is due to ischemic heart disease who are at least 40 days’ post-MI and at least 90 days postrevascularization, and with NYHA class II or III HF despite GDMT, an ICD is recommended if meaningful survival of greater than 1 year is expected.S7.1.2-1,S7.1.2-2

I A 2. In patients with LVEF of 30% or less that is due to ischemic heart disease who are at least 40 days’ post-MI and at least 90 days postrevascularization, and with NYHA class I HF despite GDMT, an ICD is recommended if meaningful survival of greater than 1 year is expected.S7.1.2-2,S7.1.2-3

Value Statement: High

Value (LOE: B-R) 3. A transvenous ICD provides high value in the primary prevention of SCD particularly when the patient’s risk of death due to a VA is deemed high and the risk of nonarrhythmic death (either cardiac or noncardiac) is deemed low based on the patient’s burden of comorbidities and functional status.S7.1.2-4

I B-R 4. In patients with NSVT due to prior MI, LVEF of 40% or less and inducible sustained VT or VF at electrophysiological study, an ICD is recommended if meaningful survival of greater than 1 year is expected.S7.1.2-5

Downloaded from http://ahajournals.org by on October 7, 2026