Sudden cardiac death electrocardiogram

Electrocardiogram

An ECG may be helpful in the diagnosis of Sudden cardiac death. Findings on ECG associated with sudden cardiac arrest include:

• Sinus tachycardia (39%)
• Abnormal T-wave inversions (30%)
• Prolonged QT interval (26%)
• Left/right atrial abnormality (22%)
• LVH (17%)
• Abnormal frontal QRS axis (17%)
• Delayed QRS-transition zone in precordial leads (13%)
• Pathological Q waves (13%)
• intraventricular conduction delays (9%)
• Multiple premature ventricular contractions (9%)
• Normal ECG (9%)

2017AHA/ACC/HRS Guideline for management of sudden cardiac arrest and ventricular arrhythmia

Class I (Level of Evidence: B)

Ambulatory ECG monitoring is recommended in patients with symptoms of syncope, presyncope, palpitation suspected ventricular arrhythmia

Class of recommendation	Level of evidence	Recommendation for ECG and exercise tredmile test
1	B	In patients with wide complex tachycardia and hemodynamically stable, 12 leads ECG should be obtained
1	B	Exercise stress test should be obtained in patients suspected arrhythmia-related exercise such as ischemic heart disease or cathecolaminergic polymorphic ventricular tachycardia
1	B	In patients with documented ventricular arrhythmia, 12 leads ECG should be obtained during sinus rhythm for evaluation of underlying heart disease

X-ray

A chest x-ray may be helpful in the diagnosis of the underlying cause of cardiac arrest such as cardiomegally, pulmonary congestion, massive pericardial effusion, widening aorta silhouette.

Echocardiography or Ultrasound

Echocardiography may be helpful in the diagnosis the cause of lethal arrhythmia and sudden cardiac arrest by assessment of the following:

• Regional wall motion abnormality
• Systolic function of left ventricle
• Evidence of myocardial infarction
• Valvular heart disease such as aortic stenosis
• Right ventricular cardiomyopathy
• Pericardial effusion, Tamponade
• Aorta dissection