Updated: 1/27/2019

Supraventricular Tachycardia

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Snapshot
  • A 28-year-old woman presents to the emergency department for palpitations and lightheadedness. She reports that her symptoms began approximately 20 minutes ago and it has not subsided. Medical history is significant for hyperthyroidism. Vital signs are significant for a blood pressure of 135/95 mmHg and a pulse of 155/min. An electrocardiogram is performed that shows a narrow QRS-complex tachyarrhythmia. Carotid sinus massage is performed and her symptoms do not improve. Intravenous adenosine is instituted and her pulse decreases to 79/min.  
Introduction
  • Definition
    • a tachyarrhythmia that originates above the ventricles (e.g., atrial or atrioventricular node tissues)
      • also known paroxysmal supraventricular tachycardia (SVT)
  • Epidemiology
    • precipitating factors
      • excessive caffeine or alcohol
      • hyperthyroidism
      • illicit drug use
  • Types
    • atrial fibrillation 
    • atrial flutter 
    • focal atrial tachycardia
    • multifocal atrial tachycardia 
    • atrioventricular reentrant tachycardia
    • atrioventricular nodal reentrant tachycardia
    • Wolff-Parkinson-White syndrome 
  • Etiology
    • reentrant circuit involved atrial and/or atrioventricular nodal tissue
  • Associated conditions
    • acute myocardial infarctions
    • preexcitation syndromes
    • atrial septal defects
    • chronic lung disease
Presentation
  • Symptoms
    • palpitations
    • anxiety
    • presyncope/lightheadedness
    • chest pain
  • Physical exam
    • tachycardia
Studies
  • Electrocardiogram 
    • tachycardia
    • narrow or wide QRS complex
      • if a wide QRS complex is noted, it must be differentiated from a ventricular tachycardia
      • a wide QRS complex can be seen in SVT if there is
        • bundle branch block
        • accessory pathway
  • Holter monitor
    • consider a 24-hour Holter monitor in patients if the tachycardia is not present
Differential
  • Atrial fibrillation 
    • differentiating factor
      • narrow QRS complex with an irregularly irregular rhythm
Treatment
  • Conservative
    • vagal maneuvers 
      • indication
        • first-step in management in a stable patient
      • examples
        • carotid sinus massage
        • Valsalva
        • facial immersion in ice or a cold wet towel
  • Medical
    • intravenous adenosine   
      • indication
        • administered in stable patients who are unresponsive to vagal maneuvers
  • Procedural
    • synchronized cardioversion
      • indication
        • performed in hemodynamically unstable patients
    • radiofrequency catheter ablation
      • indication
        • best long-term therapy for SVT
Complications
  • Tachycardia-mediated cardiomyopathy
 

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Questions (4)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Volume  
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Urine  
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2
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(M2.CV.203) A 30-year-old woman with no significant past medical history presents to the emergency department stating that her heart has been racing for the past 4 hours. She denies experiencing any chest pain, shortness of breath, weakness, or confusion. Her vital signs are as follows: T 99F, HR 180, RR 14, BP 130/85, SaO2 100%. Her physical exam is normal aside from obvious tachycardia on cardiovascular exam. Her EKG is shown in Figure A, and it remains unchanged after Valsalva maneuver. Which of the following drugs should be administered at this time? Review Topic

QID: 104209
FIGURES:
1

Nifedipine

0%

(0/2)

2

Adenosine

100%

(2/2)

3

Low-dose aspirin

0%

(0/2)

4

Fentanyl followed by synchronized cardioversion

0%

(0/2)

5

Esmolol

0%

(0/2)

M2

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