| SVT Type | ECG Characteristics | Pathology/Associations | Management |
|---|---|---|---|
| Atrial Fibrillation (AF) | π· Irregular R-R intervals | ||
| π· No clear P waves | |||
| π· Chaotic/erratic baseline atrial activity | π· Multiple foci in atria firing chaotically | ||
| π· Associated with HTN, CAD, rheumatic heart disease, catecholamine excess, hyperthyroidism, or atrial enlargement | π· Rate control and anticoagulation | ||
| π· Rhythm control with anti-arrhythmic and/or atrial fibrillation ablation | |||
| Atrial Flutter | π· Regular βsawtoothβ baseline | ||
| π· Flutter waves | π· Re-entrant circuit in the right atrium at ~300 bpm | ||
| π· Results in regular atrial contractions with ventricular rates of 150, 100, or 75 | π· Similar approach as AF | ||
| π· Atrial flutter ablation is first-line management | |||
| Multifocal Atrial Tachycardia (MAT) | π· Irregular | ||
| π· Three or more morphologically distinct P waves | |||
| π· Variable RR and PR intervals | π· Multiple ectopic foci in atrium firing and competing | ||
| π· Associated with severe pulmonary disease (e.g., COPD) or catecholamine excess | π· Treat underlying disease (improve oxygenation and ventilation) | ||
| Sinus Tachycardia | π· Regular | ||
| π· Clear P waves before QRS and QRS after every P wave | π· Associated with pain, infection, exercise, hypovolemia, fear, stress, catecholamine excess, hypoxia, anemia, pulmonary embolus | π· Treat underlying cause | |
| Atrioventricular Nodal Reentrant Tachycardia (AVNRT) | π· Regular | ||
| π· Narrow QRS | |||
| π· No discernible P waves (buried in QRS) or retrograde P waves | π· Reentrant rhythm involving fast and slow pathways in the AV node | ||
| π· Terminates quickly with AV blocking maneuvers | π· Vagal maneuvers (Valsalva, carotid massage) or adenosine | ||
| Atrioventricular Reciprocating Tachycardia (AVRT) | π· Regular | ||
| π· Narrow QRS complex | |||
| π· P waves may or may not be discernible depending on rate | π· Reentrant rhythm involving the AV node and an accessory pathway | ||
| π· Wolf-Parkinson-White syndrome is a type of AVRT | π· Vagal maneuvers (Valsalva, carotid massage) or adenosine | ||
| Wolf Parkinson-White Syndrome (WPW) | π· Delta waves | ||
| π· Short PR interval | |||
| π· Widened QRS complex | π· Type of AVRT | ||
| π· Can conduct antegrade from the atrium to the ventricle resulting in a pre-excitation pattern on ECG (delta wave) | |||
| π· Can be familial or associated with atrial fibrillation | π· Procainamide | ||
| π· Avoid AV node blockers | |||
| First-degree AV block | π· PR interval prolonged >200 ms | ||
| π· 200 ms = 1 Large square | π· Most commonly due to fibrosis and sclerosis of the conduction system | ||
| π· Second most common cause β ischemic heart disease | |||
| π· May present in young athletes due to increased vagal tone | |||
| π· Associated with Ξ²-blockers, calcium channel blockers, adenosine, digoxin, amiodarone | π· No treatment required unless symptomatic | ||
| Second-degree AV block (Mobitz I, Wenckebach) | π· PR progressively lengthens until a QRS complex is dropped | π· Increased vagal tone | |
| π· Can be seen with drug intoxication (e.g., Ξ²-blockers, digitalis) | π· No treatment unless symptomatic | ||
| π· Atropine or temporary pacemaker if needed | |||
| Second-degree AV block (Mobitz II) | π· Dropped QRS complexes not preceded by PR lengthening | π· Increased vagal tone | |
| π· Can be seen with drug intoxication (e.g., Ξ²-blockers, digitalis) | |||
| π· Risk of progression to complete heart block | π· Beta-1 agonists (e.g., isoproterenol, dobutamine) and temporary pacing | ||
| π· Permanent pacemaker unless the cause is reversible | |||
| Third-degree AV block (Complete heart block) | π· Complete dissociation between P waves and QRS complexes | ||
| π· More P waves than QRS complexes because atrial rate is faster than ventricular rate | π· Can be a complication of late Lyme disease | π· Atropine, temporary pacing | |
| π· Permanent pacemaker unless the cause is reversible (e.g., medications) |
Atrial fibrillation
Atrial flutter
Multifocal atrial tachycardia
Sinus tachycardia
AVNRT *
AVRT ** (WPW)
Wolf-Parkinson-White syndrome
First-degree AV block
Second-degree AV block (Mobitz I)
Second-degree AV block (Mobitz II)
Third-degree AV block (Complete heart block)