I. Etiology and pathogenesis: Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis includes granulomatous polyangiitis (GPA)/Wegener’s granulomatosis (WG), microscopic polyangiitis (MPA) and eosinophilic granulomatous vasculitis (EGPA)/allergic granulomatous vasculitis (AGPA)/Churg-strauss syndrome (CSS). ANCA is a useful tool for diagnosis. All three vascular inflammatory diseases can involve the heart, most commonly in EGPA, where cardiac involvement reaches 50-62% and is a major cause of early death and poor prognosis. There are two main mechanisms of cardiac involvement: ischemia due to vasculitis and myocardial infiltration by eosinophils. The typical GPA has the triad of “upper respiratory tract, lung and kidney”, and EGPA often presents with allergic rhinitis, asthma and other allergic prodromal symptoms, accompanied by eosinophilic tissue infiltration, while MPA can be differentiated from other small vessel vasculitis by its lack of granuloma formation. Comorbid myocardial damage manifested by myocarditis, heart failure, valvular disease (especially mitral regurgitation) and pericardial effusion, and even sudden cardiac death, may be combined with pulmonary hypertension secondary to pulmonary disease. III. Diagnosis: The classification criteria of ANCA-associated vasculitis are met. Myocardial involvement is particularly common in EGPA, and more often in ANCA-negative cases. Electrocardiogram and 24-hour ambulatory ECG show multiple arrhythmias. Given the lack of cardiac symptoms and normal ECG in 38% of patients with EGPA with combined myocardial damage, all patients with EGPA require complete echocardiography (UCG) and/or cardiac MRI (CMRI). FDG-PET can identify fibrosis and inflammation that are difficult to distinguish with CMRI. IV. Risk stratification for sudden death prevention: See “Myocardial damage in aortitis”. V. Treatment Glucocorticoids combined with CTX is the classical treatment regimen. IVIG can be an effective treatment option for those for whom conventional treatment regimens are ineffective. 1990 ACR classification criteria for granulomatous polyangiitis: 1. Nasal or oral inflammation: painful or painless oral ulcers, purulent or bloody nasal secretions. 2, abnormal chest radiograph: chest radiograph is nodules, fixed infiltrative foci or cavities. 3, abnormal urine sediment: microscopic hematuria (RBC>5/high magnification view) or the presence of red blood cell tubular pattern. 4. Pathological granulomatous inflammatory changes: neutrophil infiltration in the arterial wall or periarterial, or extravascular (arterial or microarterial) areas. GPA can be diagnosed when 2 or more of them are met, and the sensitivity and specificity of diagnosis are 88.2% and 92.0%, respectively. Diagnostic points of microscopic polyarteritis: 1, middle-aged and elderly, more common in males. 2, Presence of symptoms of systemic inflammatory diseases of joints, eyes, ears, heart, gastrointestinal tract, etc. 3, renal damage manifestations: proteinuria, hematuria or (and) acute progressive renal insufficiency, etc. 4, pulmonary hemorrhage: chest X-ray shows small vesicular infiltrative shadow, need to exclude pulmonary edema or infection. 5, renal biopsy shows focal segmental necrotizing glomerulonephritis with thylakoid proliferation and crescent formation. 6, Skin or other visceral biopsy shows leukocytoclastic vasculitis. 7. Positive P-ANCA. There is no uniform diagnostic criteria for this disease, and the above conditions contribute to the diagnosis of MPA. 1990 ACR classification criteria for eosinophilic granulomatous polyangiitis: 1, asthma: history of wheezing or diffuse high-pitched sounds on expiration. 2, Eosinophilia: >10% eosinophils in the white blood cell count. 3, single or multiple neuropathy: mononeuritis, multiple mononeuritis, or polyneuritis (i.e., glove/glove-like distribution) due to systemic vasculitis. 4, Non-fixed pulmonary infiltrates. 5, Sinusitis: history of acute or chronic sinus pain or pressure, or imaging showing sinus opacification. 6, extravascular eosinophilic infiltration: pathology shows eosinophilic infiltration in the periphery of arteries, microarteries, and veins. EGPA can be diagnosed when 4 or more items are met.