Sudden cardiac death diagnostic study of choice

Diagnostic Criteria

• The diagnosis of sudden cardiac arrest is made when the following diagnostic criteria are met:

• Absence of a palpable pulse of the heart
• Absent carotid pulse
• Gasping respiration or NO respiration
• Loss of consciousness due to cerebral hypoperfusion

Components	Assessment and findings
Symptoms	Symptoms related to arrhythmia Palpitations, lightheadedness, syncope, dyspnea, chest pain, cardiac arrest Symptoms related to underlying heart disease: Dyspnea at rest or on exertion, orthopnea, paroxysmal nocturnal dyspnea, chest pain, edema Precipitating factors: Exercise, emotional stress
Past medical history	Heart disease: Coronary, valvular (mitral valve prolapse), congenital heart disease Thyroid disease Acute kidney injury Chronic kidney disease Electrolyte abnormalities  Stroke,embolic events  Lung disease  Epilepsy (arrhythmic syncope can be misdiagnosed as epilepsy)  Alcohol, illicit drug use  Use of over-the-counter medications caused QT prolongation and torsades de pointes  Unexplained motor vehicle accident
Medications	Antiarrhythmic medications  Medication with QT prolongation and torsades de pointes effect Cocaine,amphetamines Anabolic steroids  Medication-medication interaction that could cause QT prolongation and torsades de pointes
Family history	SCD, SCA, unexplained drowning in a first-degree relative SIDS, repetitive spontaneous pregnancy losses concerning cardiac channelopathies  IHD  Cardiomyopathy: Hypertrophic,dilated, ARVC Congenital heart disease  Cardiac channelopathies: Long QT, Brugada, Short QT, CPVT  Arrhythmias: conduction disorders, pacemakers/ICDs Neuromuscular disease associated with cardiomyopathies  Muscular dystrophy Epilepsy

Symptoms

• Symptoms related to arrhythmia or underlying heart disease within one hour before cardiac arrest may include the following:

• Palpitations
• lightheadedness
• syncope
• dyspnea
• chest pain
• cardiac arrest
• Dyspnea at rest or on exertion
• orthopnea
• paroxysmal nocturnal dyspnea
• chest pain, edema

Physical Examination

• Patients with cardiac arrest usually appear cyanotic.
• Physical examination may be remarkable for:

• Heart rate and regularity, blood pressure
• Jugular venous pressure
• Murmurs
• Pulses, bruits
• Edema
• Sternotomy scars

Laboratory Findings

• An elevated concentration of brain natriuretic peptide (BNP) predicts has been shown as the predictor of ventricular arrhythmia and sudden cardiac death.

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%)