Updated: 2/2/2020

Multifocal Atrial Tachycardia

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Snapshot
  • A 72-year-old man is admitted to the medicine floor for a chronic obstructive pulmonary disease exacerbation. On the second day, he reports feeling lightheaded and having some chest pain. His telemetry at that time reveals an irregular rhythm with a pulse of 120/min. Electrocardiogram reveals an irregularly irregular rhythm, tachycardia, discrete P waves before every QRS complex, and at least 3 different P wave morphologies.
Introduction
  • Clinical definition
    • an atrial arrhythmia characterized by irregular and rapid rhythm
      • associated with pulmonary pathologies
  • Epidemiology
    • risk factors
      • chronic lung disease
  • Etiology 
    • decompensated chronic lung disease
      • chronic obstructive pulmonary disease (COPD) is the most common underlying illness
    • heart failure
    • structural heart damage
    • methylxanthine toxicity
  • Pathogenesis
    • multiple sites of competing atrial activity causes irregular atrial tachycardia with multiple P wave morphologies
  • Associated conditions
    • COPD
  • Prognosis
    • mortality is high but often due to multiple medical comorbidities in these patients rather than from MAT itself
Presentation
  • Symptoms
    • may be asymptomatic
    • symptoms may be precipitated by exacerbation of underlying disease, such as COPD 
      • palpitations
      • shortness of breath
      • lightheadedness
      • syncope
      • chest pain
  • Physical exam
    • often hypoxic at baseline
    • rapid and irregular pulse
Studies
  • Electrocardiogram 
    • irregularly irregular rhythm with > 100 beats per minute
    • polymorphic P waves
      • at least 3 different P wave forms
    • discrete P waves before each QRS complex
    • PR interval varies from beat to beat
  • Making the diagnosis
    • based on clinical presentation and electrocardiogram 
Differential
  • Atrial fibrillation 
    • distinguishing factor
      • electrocardiogram with atrial fibrillation (irregularly irregular heartbeat with no discrete P waves before each QRS complex) rather than MAT
  • Atrial flutter 
    • distinguishing factor
      • electrocardiogram shows rapid regular rhythm and “sawtooth” appearance of the waves
  • Premature atrial contractions
    • palpitations and ectopic P-waves with a beat earlier than expected 
Treatment
  • Management approach
    • avoid β-blockers
      • patients typically have underlying lung disease
      • β-blockers can cause bronchospasms
    • oxygen is usually given first followed by medication
  • Medical
    • non-dihydropyridine calcium channel blockers
      • indication
        • for all patients
      • mechanism of action
        • this class of calcium channel blockers directly act on the heart
        • decreases atrial activity
        • slows atrioventricular node conduction
      • drugs 
        • diltiazem
        • verapamil
Complications
  • Emboli
  • Myocardial infarction
 

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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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(M3.CV.15.13) An 86-year-old man with a history of COPD, hypertension, and diabetes presents to the emergency department with dyspnea and palpitations. He states his symptoms started 1 hour ago and have persisted. His temperature is 100.0°F (37.8°C), blood pressure is 157/98 mm Hg, pulse is 130/min, respirations are 23/min, and oxygen saturation is 90% on room air. Physical exam is notable for digital clubbing, bilateral wheezing, and an obese abdomen. An ECG is performed as seen in Figure A. The patient is given continuous albuterol-ipratropium nebulizers with minimal improvement. Which of the following is the best next step in management? Review Topic | Tested Concept

QID: 102954
FIGURES:
1

Amiodarone

33%

(1/3)

2

Aspirin

0%

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3

Digoxin

0%

(0/3)

4

Diltiazem

67%

(2/3)

5

Metoprolol

0%

(0/3)

L 3 E

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Evidences (3)
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