Makindo Medical Notes

Related Subjects: |ECG-QT interval |Brugada Syndrome |Long QT syndrome (LQTS) Acquired |Long QT syndrome (LQTS) Congenital |Torsades de Pointes |Ventricular Fibrillation |Ventricular Tachycardia |Resuscitation - Adult Tachycardia Algorithm |Automatic Implantable Cardioverter Defibrillator (AICD)

Although the occurrence of sudden cardiac death (SCD) in a young person is a rare event, it is traumatic and often widely publicized. In older patients SCD is mainly due to coronary artery disease (CAD), while at younger age cardiomyopathies and ion-channelopathies predominate

About

• SCD in young patients is significantly more prevalent in young males
• College athletes x2-3 general population e.g. ARVC seen

Heritable

• Hypertrophic cardiomyopathy (HCM) 1:500 persons
• Arrhythmogenic right ventricular cardiomyopathy (ARVC)
• Dilated cardiomyopathy
• Left ventricular non-compaction cardiomyopathy
• Heritable channelopathies including long QT syndrome (LQTS) 1 in :2000 persons for LQTS
• Short QT syndrome
• Brugada syndrome (BrS)
• Catecholaminergic polymorphic ventricular tachycardia

Structural congenital heart disease (CHD)

• Ventricular dysfunction in combination with scarring, hypertrophy and fibrosis increases the likelihood of SCD in many patients with severe and, to a lesser degree, mild forms of CHD.
• Tetralogy of Fallot, a form of CHD which is well-studied due to its relative prevalence and the availability of long follow-up after surgical palliation, have SCD rates that average 0.1 - 0.2% / year

Structurally normal heart

• Brugada syndrome
• Congenital Long QT syndrome
• Acquired Long QT syndrome
• Pre excitation syndrome - WPW with AF and a fast ventricular response classically
• Commotio cordis - young adults with low-impact precordial trauma with a projectile object such as a baseball, hockey puck, or fist or rubber bullet that hits on the T wave like an R on T
• Catecholamine induced VT

Structurally abnormal heart

• IHD - Acute MI/ACS
• Arrhythmogenic RV dysplasia
• Hypertrophic cardiomyopathy
• Aortic stenosis

Causes

Investigations

• Various cardiovascular screening strategies have been proposed, including ECG, history and physical examination, and echocardiogram singly and in combination. ECG alone may suffice.
• ECG is a sensitive and efficient screening test for most diagnoses that cause SCD in young people and may be prophylactically treated, including LQTS, WPW, HCM, and BrS

ECG Findings that are associated with increased risk of SCD

• A corrected QT interval (QTc) in subjects >55 years of age a prolonged QTc (>450 ms in men and >470 ms in women) was associated with a three-fold increased risk of SCD
• T-wave inversions, wide QRS-T angle, and prolonged QRS duration due to either left bundle branch block (LBBB) or intraventricular conduction delay but not right bundle branch block
• Non sustained VT, Echo - poor LV function

Management

• For patients who have been identified as being at high risk for SCD, it may be appropriate to consider the placement of an ICD for primary prevention however the risk to benefit relationship that pertains to ICD use is less clearly developed
• Children and young adults may have a relatively high rate of complications associated with devices, including frequency of inappropriate shocks, lead malfunctions and difficulties in ICD placement related to intracardiac anatomy and small size

References

• Sudden cardiac death in the young