Sudden Cardiac Death SCD

Automatic subtitles available in: Español. Sudden Cardiac Death (SCD) can be defined as natural death from cardiac causes heralded by abrupt loss of consciousness within 1 hour of the onset of an acute change in cardiovascular status.
Causes of sudden cardiac death: Coronary artery disease: 80%. CAD is by and large, the most important cause of SCD
Cardiomyopathy: 15%
Left ventricular hypertrophy is a strong independent risk factor for SCD
ARVD is being recognized as an important cause of exercise induced SCD
Aortic stenosis
Channelopathies – Long QT syndrome, Brugada syndrome, Short QT syndrome
Coronary anomalies – Anomalous origin of left coronary artery from pulmonary artery (ALCAPA)
Aortic valve endocarditis
Myocarditis
Sarcoidosis
Operated Tetralogy of Fallot
Predictors of SCD: LV ejection fraction: LV ejection fraction less than 30% is the single most powerful independent predictor of SCD. The incidence of SCD increases as the ejection fraction decreases, but the proportion of SCD to all deaths decreases due to increase in deaths due to pump failure.
NYHA class is similar to LV ejection fraction, but patients may shift from one class to another frequently.
Non sustained ventricular tachycardia (NSVT) is a predictor in a small group of patients.
Signal averaged ECG – Late potentials predict SCD. It has a high negative predictive value. It is not useful in patients with bundle branch block.
QRS duration – higher QRS duration is an indicator. QRS duration – higher QRS duration is an indicator. T wave alternans – very good marker of SCD in ischemic and non-ischemic cardiomyopathy. QT dispersion is the variability in QT interval between the leads – does not give any meaningful prognostic information.
QT interval variability is the variability in QT interval during the period of ECG recording – predictive of SCD, but more studies are needed.
Baroreceptor sensitivity – sensitivity of change in heart rate with change in blood pressure. Heart rate variability in short term and long term – short term heart rate variability is a predictor of SCD while long term heart rate variability is a predictor of total mortality.
Heart rate turbulence – transient slowing of heart rate after a ventricular ectopic beat followed by an acceleration. Heart rate turbulence is an important predictor of SCD.
Heart rate recovery following a treadmill exercise test is a predictor of SCD. Inducible ventricular tachycardia on EP study.