Esmolol Vs Diltiazem in the Treatment of Postoperative AF/AFL
Esmolol Vs Diltiazem in the Treatment of Postoperative AF/AFL
Background: Supraventricular tachyarrhythmias are common after open heart surgery. Possible causative factors for these arrhythmias include operative trauma, atrial ischemia, electrolyte imbalances, pericardial irritation, and excess catecholamines. Two agents commonly used to control ventricular rate in atrial fibrillation or atrial flutter (AF/AFL) are ß-blockers and calcium channel blockers.
Methods and Results: This randomized study was designed to compare the safety and efficacy of intravenous diltiazem versus intravenous esmolol in patients with postoperative AF/AFL after coronary bypass surgery and/or valve replacement surgery. A comparative cost analysis was also performed. Thirty patients received either esmolol (n = 15) or diltiazem (n = 15) for AF/AFL. During the first 6 hours of treatment, 66.6% of esmolol-treated patients converted to sinus rhythm compared with 13.3% of the diltiazem-treated patients (P < .05). At 24 hours, 66.6% of the diltiazem group converted to SR compared with 80% of the esmolol group (not significant). Drug-induced side effects, time to rate control (<90 beats/min), number of patients requiring cardioversion, and length of hospitalization were similar for the two groups. The drug cost/successfully treated patient for esmolol versus diltiazem was $254 versus $437 at 6 hours and $529 versus $262 at 24 hours.
Conclusions: Although this is a small study, it suggests that esmolol is more effective in converting patients to normal sinus rhythm than diltiazem during the initial dosing period. No differences in conversion rates were observed between the two groups after 24 hours. Additional studies are needed to confirm whether esmolol is the initial drug of choice in patients with postoperative AF/AFL after coronary bypass surgery.
Supraventricular tachyarrhythmias are common after coronary bypass surgery. The frequency of clinically important arrhythmias such as atrial fibrillation (AF) typically varies from 10% to 40%. The majority of these arrhythmias occur 24 hours to 1 week after surgery, with the highest incidence occurring on postoperative days 2 and 3. Several causative factors have been implicated in the genesis of these arrhythmias. These factors include pericarditis, use of inotropic agents, ischemic injury, preoperative use of ß-blockers, atrial trauma, and possibly the residual effects associated with the use of cardioplegic solutions. In addition, neurohumoral factors may play a significant role. Serum catecholamines are elevated after surgery, and ß-blockade has been shown to reduce the incidence of AF after cardiovascular surgery. Although postoperative AF is seldom life-threatening, it can cause significant morbidity including hypotension, congestive heart failure, and stroke. Postoperative AF has been shown to increase the length of hospitalization and increase overall coronary bypass surgery costs by 16%.
The optimal treatment strategy for postoperative arrhythmias, especially AF after coronary bypass surgery, is not well established. Commonly used therapeutic approaches include the use of rate-controlling drugs such as digoxin, ß-blockers, calcium antagonists, and pharmacologic or electrical cardioversion. Several prophylactic treatment regimens have been shown to reduce the incidence of AF but at a significant cost, an increased risk of side effects, and little effect on length of stay. The majority of studies with digoxin have not been impressive. Digoxin is ineffective when used prophylactically to prevent AF. When used for rate control, digoxin has been shown to be less effective than diltiazem during the first 6 hours, after which no differences exist. Two classes of drugs, ß-blockers and nondihydropyridine calcium channel blockers, have shown benefit when used to treat patients who have AF after bypass surgery. The advantages of these two classes of drugs, particularly esmolol and diltiazem, are that both drugs are relatively inexpensive and can be given intravenously.
The purpose of this study was to compare the efficacy of intravenous esmolol versus intravenous diltiazem in patients who had atrial fibrillation/atrial flutter (AF/AFL) after coronary bypass surgery. Because postoperative arrhythmias are influenced by an increased adrenergic state, the authors hypothesized that patients who have supraventricular tachyarrhythmias, for example, AF/AFL after major heart surgery, would have a higher rate of cardioversion if treated with ß-blockers than patients receiving an intravenous calcium channel antagonist. In addition, time to rate control and a projected drug cost per successfully converted patient was done for each group.
Background: Supraventricular tachyarrhythmias are common after open heart surgery. Possible causative factors for these arrhythmias include operative trauma, atrial ischemia, electrolyte imbalances, pericardial irritation, and excess catecholamines. Two agents commonly used to control ventricular rate in atrial fibrillation or atrial flutter (AF/AFL) are ß-blockers and calcium channel blockers.
Methods and Results: This randomized study was designed to compare the safety and efficacy of intravenous diltiazem versus intravenous esmolol in patients with postoperative AF/AFL after coronary bypass surgery and/or valve replacement surgery. A comparative cost analysis was also performed. Thirty patients received either esmolol (n = 15) or diltiazem (n = 15) for AF/AFL. During the first 6 hours of treatment, 66.6% of esmolol-treated patients converted to sinus rhythm compared with 13.3% of the diltiazem-treated patients (P < .05). At 24 hours, 66.6% of the diltiazem group converted to SR compared with 80% of the esmolol group (not significant). Drug-induced side effects, time to rate control (<90 beats/min), number of patients requiring cardioversion, and length of hospitalization were similar for the two groups. The drug cost/successfully treated patient for esmolol versus diltiazem was $254 versus $437 at 6 hours and $529 versus $262 at 24 hours.
Conclusions: Although this is a small study, it suggests that esmolol is more effective in converting patients to normal sinus rhythm than diltiazem during the initial dosing period. No differences in conversion rates were observed between the two groups after 24 hours. Additional studies are needed to confirm whether esmolol is the initial drug of choice in patients with postoperative AF/AFL after coronary bypass surgery.
Supraventricular tachyarrhythmias are common after coronary bypass surgery. The frequency of clinically important arrhythmias such as atrial fibrillation (AF) typically varies from 10% to 40%. The majority of these arrhythmias occur 24 hours to 1 week after surgery, with the highest incidence occurring on postoperative days 2 and 3. Several causative factors have been implicated in the genesis of these arrhythmias. These factors include pericarditis, use of inotropic agents, ischemic injury, preoperative use of ß-blockers, atrial trauma, and possibly the residual effects associated with the use of cardioplegic solutions. In addition, neurohumoral factors may play a significant role. Serum catecholamines are elevated after surgery, and ß-blockade has been shown to reduce the incidence of AF after cardiovascular surgery. Although postoperative AF is seldom life-threatening, it can cause significant morbidity including hypotension, congestive heart failure, and stroke. Postoperative AF has been shown to increase the length of hospitalization and increase overall coronary bypass surgery costs by 16%.
The optimal treatment strategy for postoperative arrhythmias, especially AF after coronary bypass surgery, is not well established. Commonly used therapeutic approaches include the use of rate-controlling drugs such as digoxin, ß-blockers, calcium antagonists, and pharmacologic or electrical cardioversion. Several prophylactic treatment regimens have been shown to reduce the incidence of AF but at a significant cost, an increased risk of side effects, and little effect on length of stay. The majority of studies with digoxin have not been impressive. Digoxin is ineffective when used prophylactically to prevent AF. When used for rate control, digoxin has been shown to be less effective than diltiazem during the first 6 hours, after which no differences exist. Two classes of drugs, ß-blockers and nondihydropyridine calcium channel blockers, have shown benefit when used to treat patients who have AF after bypass surgery. The advantages of these two classes of drugs, particularly esmolol and diltiazem, are that both drugs are relatively inexpensive and can be given intravenously.
The purpose of this study was to compare the efficacy of intravenous esmolol versus intravenous diltiazem in patients who had atrial fibrillation/atrial flutter (AF/AFL) after coronary bypass surgery. Because postoperative arrhythmias are influenced by an increased adrenergic state, the authors hypothesized that patients who have supraventricular tachyarrhythmias, for example, AF/AFL after major heart surgery, would have a higher rate of cardioversion if treated with ß-blockers than patients receiving an intravenous calcium channel antagonist. In addition, time to rate control and a projected drug cost per successfully converted patient was done for each group.
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