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Upon completion of the chapter, the reader will be able to:

  1. Describe the phases of cardiac action potential, compare and contrast cardiac myocyte ion changes corresponding to each phase, and explain the relationship between the cardiac action potential and the electrocardiogram (ECG).

  2. Describe the modified Vaughan Williams classification of antiarrhythmic drugs, and compare and contrast the effects of available antiarrhythmic drugs on ventricular conduction velocity, refractory period, automaticity, and inhibition of ion flux through specific myocardial ion channels.

  3. Compare and contrast risk factors for and features, mechanisms, etiologies, symptoms, and goals of therapy of (a) sinus bradycardia, (b) atrioventricular (AV) nodal block, (c) atrial fibrillation (AF), (d) paroxysmal supraventricular tachycardia (PSVT), (e) ventricular premature depolarizations (VPDs), (f) ventricular tachycardia (VT, including torsades de pointes [TdP]), and (g) ventricular fibrillation (VF).

  4. Compare and contrast appropriate nonpharmacologic and pharmacologic treatment options for sinus bradycardia and AV nodal block.

  5. Compare and contrast mechanisms of action of drugs used for ventricular rate control, conversion to sinus rhythm and maintenance of sinus rhythm in patients with AF, and explain the importance of anticoagulation for patients with AF.

  6. Discuss nonpharmacologic methods for termination of PSVT, and compare and contrast mechanisms of action of drugs used for acute termination of PSVT.

  7. Compare and contrast the role of drug therapy versus nonpharmacologic therapy for long-term prevention of PSVT recurrence.

  8. Describe the role of drug therapy for management of asymptomatic and symptomatic VPDs.

  9. Compare and contrast mechanisms of action of drugs used for treatment of acute episodes of VT, and describe options and indications for nonpharmacologic treatment of VT and VF.

  10. Design individualized drug therapy treatment plans for patients with (a) sinus bradycardia, (b) AV nodal block, (c) AF, (d) PSVT, (e) VPDs, (f) VT (including TdP), and (g) VF.


The heart functions via both mechanical and electrical activity. Mechanical activity of the heart refers to atrial and ventricular contraction, the mechanism by which blood is delivered to tissues. When circulated blood returns to the heart via venous circulation, blood enters the right atrium. Right atrial contraction and changes in right ventricular pressure result in delivery of blood to the right ventricle through the tricuspid valve. Right ventricular contraction pumps blood through the pulmonic valve through the pulmonary arteries to the lungs, where blood becomes oxygenated. The blood then flows through the pulmonary veins into the left atrium. Left atrial contraction and changes in left ventricle (LV) pressure result in delivery of blood through the mitral valve into the LV. Contraction of the LV results in pumping of blood through the aortic valve and to the tissues of the body.

Mechanical activity of the heart (contraction of the atria and ventricles) occurs as a result of the electrical activity of the heart. The heart ...

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