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Source: Sanoski CA, Bauman JL.
The Arrhythmias. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells
BG, Posey LM, eds. Pharmacotherapy: A Pathophysiologic
Approach. 8th ed. http://accesspharmacy.com/content.aspx?aid=7972803.
Accessed June 30, 2012.
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- Paroxysmal supraventricular tachycardia (PSVT) is rapid
heart rhythm originating above ventricles that occurs episodically.
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- May occur in healthy individuals.
- Premature atrial or ventricular ectopic beats
- Hyperthyroidism
- Stimulant use (including caffeine)
- Previous myocardial infarction, mitral valve prolapse, rheumatic
heart disease, pericarditis, pneumonia, chronic lung disease, alcohol
intoxication
- Digoxin toxicity
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- PSVT arising by reentrant mechanisms includes arrhythmias
caused by atrioventricular (AV) nodal reentry, AV reentry incorporating
an anomalous AV pathway, sinoatrial (SA) nodal reentry, and intra-atrial
reentry.
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- Prevalence: ~2 cases per 1000 persons in United States.
- Incidence: 35 cases per 100,000 person-years.
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- Many patients asymptomatic or have only occasional minor
palpitations or irregular pulse.
- Patients may experience:
- Choking or pressure
sensation
- Dizziness
- Lightheadedness
- Shortness of breath
- Syncope
- Symptoms of heart failure
- Anginal chest pain
- Symptoms may be severe and even life threatening in some patients.
- Heart rate ranges from 140–240 beats/min
and is regular.
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Means of Confirmation
and Diagnosis
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- Electrocardiogram (ECG) shows regular rhythm with rate
between 140–240 beats/min.
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- May be performed if underlying causes suspected (e.g.,
hyperthyroidism, digoxin toxicity).
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Differential
Diagnosis
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- Atrial tachycardia, flutter, or fibrillation
- Atrioventricular nodal reentrant tachycardia (AVNRT)
- Sinus node dysfunction
- Ventricular tachycardia or fibrillation
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- Identify and correct underlying causes.
- Terminate acute episodes and resolve symptoms.
- Prevent recurrences.
- Avoid complications from therapy.
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- For mild to moderate symptoms, measures that increase
vagal tone to AV node (unilateral carotid sinus massage, Valsalva
maneuver) used initially.
- For severe symptoms, synchronized direct current cardioversion
(DCC) treatment of choice.
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- Used for mild to moderate symptoms if nondrug measures
fail.
- Drug selection based on QRS complex (Figure 1).
- Directly
or indirectly increase vagal tone to AV node, with digoxin.
- Depress conduction through slow, calcium-dependent tissue:
- Adenosine
- β-blockers
- Nondihydropyridine calcium channel blockers
- Depress conduction through fast, sodium-dependent tissue
- Quinidine
- Procainamide
- Disopyramide
- Flecainide
- Adenosine a drug of first choice because its short duration
of action will not cause prolonged hemodynamic compromise in patients
with wide QRS complexes who actually have ventricular tachycardia
rather than PSVT.
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