What does NICM (National Institute of Complementary Medicine) stand for in medical context?

NICM in Cardiology: Non-Ischemic Cardiomyopathy

In cardiology, NICM stands for Non-Ischemic Cardiomyopathy, which refers to a broad spectrum of disorders of the myocardium associated with mechanical or electrical dysfunction leading to inappropriate ventricular hypertrophy or dilation, without evidence of ischemia. 1

Definition and Classification

• Non-Ischemic Cardiomyopathy (NICM) encompasses disorders of the myocardium that are not caused by coronary artery disease or ischemia 1
• NICM can be either primary (genetic, acquired, or mixed) or secondary to a systemic disease process 1
• The prevalence of NICM is approximately 0.02% with an annual death rate of 25,000 in the United States 1

Types of NICM

NICM can be classified into five main variants:

1. Hypertrophic cardiomyopathy (HCM) - Prevalence 1:250 to 500 1
2. Restrictive cardiomyopathy or infiltrative diseases 1
3. Dilated cardiomyopathy (DCM) - Prevalence 1:250 to 500 1
4. Arrhythmogenic cardiomyopathy (arrhythmia of ventricular origin) - ARVD prevalence 1:2,000 to 5,000 1
5. Inflammatory cardiomyopathy 1

Clinical Presentation

• Common presentations include heart failure, arrhythmia, sudden death, and acute chest pain 1
• Symptoms often include dyspnea, edema, ascites, chest discomfort, palpitations, and syncope 1
• In patients with clinical heart failure, a primary cardiomyopathy is diagnosed in 2% to 15% of patients 1
• Patients with NICM in NYHA class I are not necessarily at low risk of ventricular arrhythmias and sudden death, particularly if they have late gadolinium enhancement on cardiac MRI 2

Diagnostic Evaluation

• Echocardiography: First-line imaging modality that provides information on ventricular function, volumes, mass, thickness, and valvular function 1
• Cardiac MRI: Provides detailed information on cardiac morphology, function, and tissue characterization; different patterns of late gadolinium enhancement (LGE) are seen in NICM 1
• Nuclear Medicine: Techniques such as SPECT and PET are used to exclude ischemia and evaluate specific types of NICM like cardiac sarcoidosis and amyloidosis 1
• Cardiac CT: Primarily used to exclude coronary artery disease as the etiology of heart failure 1

Treatment and Prognosis

• ICD therapy is recommended for patients with NICM who survive sudden cardiac arrest due to VT/VF or experience hemodynamically unstable VT or stable sustained VT 1
• In patients with NICM and septal substrate, catheter ablation can provide acceptable VT control 3
• Catheter ablation of VT in NICM is associated with lower in-hospital mortality compared to medical therapy alone 4
• Left ventricular ejection fraction (LVEF) is a significant independent risk factor for major arrhythmic events, with each 10% decrease in EF associated with a 2.3-fold increase in risk 1
• Late gadolinium enhancement on cardiac MRI is an independent predictor of ventricular arrhythmias and sudden death in both NYHA class I and class II-III patients with NICM 2

Important Clinical Trials

• DEFINITE trial and SCD-HeFT: Showed a decrease in arrhythmia-related death associated with ICD use in NICM 1
• CAT (Cardiomyopathy Trial): 104 patients with newly identified NICM and Class II/III heart failure; stopped prematurely due to lower than expected mortality rate 1
• AMIOVIRT (Amiodarone Versus Implantable Cardioverter-Defibrillator Randomized Trial): 103 patients with NICM and NSVT; no difference in survival between amiodarone and ICD therapy 1
• IMAC-2 (Intervention in Myocarditis and Cardiomyopathy): 373 patients with new-onset cardiomyopathy; showed 70% of patients had an absolute increase in EF by >10% and 25% had a normal EF at 6 months 1

Unlike ischemic cardiomyopathy, the pathophysiology of NICM is usually unclear and multifactorial, the functional consequences are global, the prognosis is generally better, and the therapeutic response is different 1.