SHA24/022002

Saudi heart 2013 SHA 24

Tachycardia • Approach • Clinical • Mechanism • ECG analysis

Clinical • Stable vs unstable

Mechanism • Reentrant • Automatic (ectopic focus fire by its own) • Triggered automatic (needs stimlus )

ECG analysis • • • •

Narrow vs wide Fast vs slow Regular vs irregular Atrial and ventricular relationship (linked or not) • P wave axis and morphology

Two concepts • Sequential depolarization • ECG records Vector of electrical current • Positive • Negative • biphasic

Automatic • • • •

Ectopic atrial focus; abnormal automaticity Abnormal P-wave morphology/axis Structurally normal hearts Tachycardia-induced cardiomyopathy

Reentrant • Accessory Connection between atrium and ventricle

Types of AP • Manifested vs concealed • Bidirectional vs unidirectional • Fast conducting vs slow

Manifested pathway • Conduct Antegrade – From atrium to ventricle – recognized by presence of delta wave on ECG

Ventricular Pre-excitation depends on competition between AV node and AP

How serious is the AP ?

• Depends on:

–Conduction velocity –Refractory period

Concealed pathway • Conduct retrograde – From the ventricle to atrium – No delta wave

Orthodromic

AVRT

Slow concealed pathway

Antidromic

AV Node Reentrant Tachycardia distinct pathways – “slow” and “fast” • Typical – Down slow, up fast • Atypical – Down fast, up slow

Atrial Tachycardia (Reentrant) • Atrial Flutter – rapid, regular flutter waves (“saw tooth”) – variable AV conduction • Atrial fibrillation – absence of discrete Pwaves – “irregularly irregular” ventricular response

Examples

Atrial tachycardia

AVRT

Thank you