Tachydysrhythmias
Basics
Description
Description
- Any disturbance of the heart's rhythm resulting in a rate >100 bpm
- Sinus tachycardia:
- Narrow complex regular rhythm at a rate of 100–150 bpm
- Max rate typically 220 minus age
- Functional response to physiologic stress caused by increased catecholamine tone or decreased vagal stimulation
- Supraventricular tachycardia (SVT):
- A narrow complex tachycardia that originates above the His bundle
- Regular SVT:
- Atrial tachycardia
- Junctional tachycardia:
- Regular tachycardia without preceding depolarization waves
- Irregular SVT:
- Atrial fibrillation (AF)
- Atrial flutter (with variable block)
- Multifocal atrial tachycardia
- Ventricular tachycardia (VT):
- ≥3 consecutive ventricular ectopic beats at a rate of 100 bpm
- Most common initiating rhythm in sudden death in patients with previous MI
- Torsades de pointes:
- Paroxysmal form of VT with undulating axis and prolonged baseline QT interval
- Secondary to either congenital or acquired abnormalities of ventricular repolarization
- Often the result of drug therapy or electrolyte disturbances
- VF:
- Oscillations without evidence of discrete QRST morphology
- Accounts for 80–85% of sudden cardiac deaths
- Frequently results from degeneration of sustained VT
Etiology
Etiology
- Sinus tachycardia:
- Acute MI
- Anemia
- Anxiety
- CHF
- Drug intoxication
- Hyperthyroidism
- Hypovolemia
- Hypoxia
- Infection
- Pain
- Pericardial tamponade
- Pulmonary embolism
- Atrial tachycardia:
- Electrolyte disturbances
- Drug toxicity (e.g., theophylline)
- Hypoxia
- Junctional tachycardia:
- AV nodal re-entry
- Myocardial ischemia
- Structural heart disease
- Pre-excitation syndromes
- Wolff–Parkinson–White (WPW) syndrome:
- Intrinsic accessory pathway
- Drug and alcohol toxicity
- AF:
- HTN
- Coronary artery disease
- Hyper-/hypothyroidism
- Alcohol intake
- Mitral valve disease
- Chronic obstructive pulmonary disease
- Pulmonary embolism
- Hypoxia
- Digoxin toxicity
- Chronic pericarditis
- Idiopathic AF
- Atrial flutter:
- Ischemic heart disease
- Valvular heart disease
- CHF
- Myocarditis
- Cardiomyopathies
- Pulmonary embolism
- Electrolyte abnormalities
- Multifocal atrial tachycardia:
- Hypoxic effects of chronic lung disease
- Theophylline toxicity
- Ventricular tachycardia:
- Dilated cardiomyopathy
- Cardiac ischemia
- Hypoxia
- Cardiac scarring/fibrosis
- Cardiac surgery or congenital anomaly repair
- Digoxin toxicity
- Long QT syndrome
- Electrolyte abnormalities
- Torsades de pointes:
- Drug toxicity (antiarrhythmic class IA and III agents, antipsychotics, antibiotics, etc.)
- Hypokalemia
- Hypomagnesemia
- Congenital QT prolongation
- Ventricular fibrillation:
- Acute MI (most common)
- Chronic ischemic heart disease
- Hypoxia
- Acidosis
- Anaphylaxis
- Electrocution
- Shock
- Hypokalemia
- Initiation of quinidine therapy
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Citation
Schaider, Jeffrey J., et al., editors. "Tachydysrhythmias." 5-Minute Emergency Consult, 6th ed., Lippincott Williams & Wilkins, 2020. Emergency Central, emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307402/all/Tachydysrhythmias.
Tachydysrhythmias. In: Schaider JJJ, Barkin RMR, Hayden SRS, et al, eds. 5-Minute Emergency Consult. Lippincott Williams & Wilkins; 2020. https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307402/all/Tachydysrhythmias. Accessed November 14, 2024.
Tachydysrhythmias. (2020). In Schaider, J. J., Barkin, R. M., Hayden, S. R., Wolfe, R. E., Barkin, A. Z., Shayne, P., & Rosen, P. (Eds.), 5-Minute Emergency Consult (6th ed.). Lippincott Williams & Wilkins. https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307402/all/Tachydysrhythmias
Tachydysrhythmias [Internet]. In: Schaider JJJ, Barkin RMR, Hayden SRS, Wolfe RER, Barkin AZA, Shayne PP, Rosen PP, editors. 5-Minute Emergency Consult. Lippincott Williams & Wilkins; 2020. [cited 2024 November 14]. Available from: https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307402/all/Tachydysrhythmias.
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