Nishimura and Holmes identified risk factors associated with sudden death in patients with hypertrophic obstructive cardiomyopathy. This can help identify patients who may require more aggressive management and closer monitoring. The authors are from the Mayo Clinic.


Major risk factors:

(1) cardiac arrest associated with ventricular fibrillation

(2) spontaneous sustained ventricular tachycardia

(3) family history of all of the following:

(3a) sudden death secondary to hypertrophic obstructive cardiomyopathy

(3b) in >= 2 first degree relatives

(3c) who are < 40 years of age.


Minor risk factors:

(1) >= 2 episodes of unexplained syncope within 1 year

(2) left ventricular wall thickness > 30 mm

(3) abnormal blood pressure during exercise with either (a) failure of blood pressure to rise > 25 mm Hg above baseline or (b) decrease by > 10 mm from the maximal blood pressure during exercise in an upright position

(4) nonsustained ventricular tachycardia demonstrated on Holter monitor or during exercise, with (a) >= 3 consecutive ventricular extrasystoles (b) with the heart rate > 120 beats per minute and (c) with duration < 30 seconds

(5) left ventricular outflow obstruction

(6) microvascular obstruction (perfusion defects on nuclear imaging or magnetic resonance imaging)

(7) high-risk genetic defect (mutations in the genes encoding the sarcoplasmic proteins)


High risk for sudden death is defined as one of the following:

(1) 1 or more major risk factors

(2) 3 or more minor risk factors


A patient at high risk for sudden death is a candidate for prophylactic implantation of an automatic defibrillator.


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