Pharmacologic therapy in patients with ventricular tachyarrhythmias.
Table 5 can be used as framework for a summary of the previous discussion on pharmacologic therapy for ventricular tachyarrhythmias. The system for grading the severity of symptoms of ventricular tachyarrhythmias, previously presented in Table 3, is arranged vertically along the left side of Table 5. Horizontally across the top, patients are grouped according to the presence or absence of structural heart disease, and those with structural heart disease are further dichotomized according to left ventricular ejection fraction. As can be seen, patients with class I symptoms should not be treated whenever possible, although in patients with reduced left ventricular function (especially coronary heart disease), an argument can be made for empirical treatment with beta-adrenoceptor blocking agents whenever possible. Patients with class II symptoms can be treated empirically with beta-adrenoceptor blocking agents. Other antiarrhythmic agents may be safer when there is no underlying structural heart disease, but this has not been proved. The use of antiarrhythmic agents other than beta-adrenoceptor blocking agents in patients with class II symptoms should probably be guided and monitored by ambulatory electrocardiographic recording and exercise tolerance testing. In the patient with hemodynamically stable ventricular tachycardia, electrophysiologic-guided therapy is probably preferable whenever possible. Encainide, flecainide, and similar drugs should be avoided when there is a possibility of residual ventricular premature depolarizations of three or more per hour. Some uncertainty remains concerning the treatment of patients with class III and class IV symptoms and no structural heart disease. Some patients may fall into a specific group that is very responsive to drug therapy. These patients should probably be treated like other patients with class III and class IV symptoms. Electrophysiologic testing may be helpful. When such patients have a reproducibly induced sustained ventricular tachyarrhythmia, it is likely that antiarrhythmic drug therapy will render the arrhythmia noninducible, and that they will do well while receiving long-term pharmacologic therapy. When such patients do not have a reproducibly induced sustained ventricular tachyarrhythmia, the main controversy is whether therapy is needed. If it is decided that such a patient needs therapy, the choice is usually between empiric amiodarone and an ICD, although catheter ablation may be helpful in selected instances. Patients with class III and class IV symptoms who have structural heart disease require therapy. Although this continues to be an evolving area of investigation, for many of these patients, the initial attempt at therapy should be pharmacologic.(ABSTRACT TRUNCATED AT 400 WORDS)
Wyse
D G
DG
Division of Cardiology, University of Calgary, Foothills Hospital, Alberta, Canada.
D000889:Anti-Arrhythmia Agents / Q000145:classification / Q000627:therapeutic use; D006801:Humans; D012720:Severity of Illness Index; D017180:Tachycardia, Ventricular / Q000188:drug therapy*
D000889:Anti-Arrhythmia Agents