Atropine-induced ventricular fibrillation: case report and review of the literature

Ventricular tachycardia and acute heart failure induced by atropine in the treatment of bradycardia: A case report and literature review

RATIONALE

Despite various advantages of laparoscopic surgical procedures, artificial pneumoperitoneum might lead to hemodynamic fluctuations including severe bradycardia and cardiac arrest. Atropine is usually proposed to treat intraoperative severe bradycardia ( < 40 beats per minute). However, atropine could induce ventricular arrhythmias, which might be life-threatening in severe case.

PATIENT CONCERNS

Here, we reported a 41-year-old female who was diagnosed with gallbladder polyps and was scheduled for laparoscopic cholecystectomy under general anesthesia.

DIAGNOSES

Bradycardia occurred suddenly during the operation and atropine was injected intravenously. Eventually the patient developed ventricular tachycardia and acute heart failure.

INTERVENTIONS

We organized an urgent consultation and the patient was treated immediately.

OUTCOMES

Fortunately, the patient experienced no complications after timely diagnosis and treatment. After 6 months of follow-up, her New York Heart Association classification was I with no complications.

LESSONS

This case highlighted that the administration of atropine to treat bradycardia may lead to ventricular tachycardia and acute heart failure, and anesthesiologists should remain vigilant to avoid potentially life-threatening consequences.

Effects of Anisodine Hydrobromide on the Cardiovascular and Respiratory Functions in Conscious Dogs

Purpose

Anisodine hydrobromide (Ani) is isolated from the medicinal plant Anisodus tanguticus (Maxim.) Pascher for clinical use. Although considerable research regarding Ani has been reported, the safety profiles of Ani are currently unknown. This study investigated the cardiorespiratory effects of Ani in conscious dogs to provide clinicians a detailed safety profile of Ani on the cardiorespiratory system.

Materials and Methods

Using the Latin square design, the study was divided into six phases, where in each phase, six telemetered beagle dogs received one dose of normal saline or sotalol hydrochloride or Ani (0.1, 0.4, 1.6, or 6.4 mg/kg). Electrocardiogram, blood pressure (BP) and respiratory parameters were collected before and after administration for 24 hours. Statistical comparisons were performed at scheduled time-points.

Results

The heart rate was significantly increased, PR and QT_CV intervals were significantly shortened in Ani 0.4, 1.6, 6.4 mg/kg treatment group after drug administration. Compared with the saline group, a significant increase in heart rate and shortening of PR, QT_CV intervals were observed in the Ani 1.6, 6.4 mg/kg treatment groups from 5 min to 4 h time-points. Diastolic and mean BP were significantly increased in Ani 1.6, 6.4 mg/kg from 1 h to 2 h time-points compared to those of the saline control. Accelerated breathing was observed in the first 20 min after Ani 0.4, 1.6, and 6.4 mg/kg treatment, although not statistically significant. Furthermore, no significant differences were observed in any of the corresponding indexes of Ani 0.1 mg/kg treatment group at different time-points compared to those of the saline group.

Conclusion

Ani may have adverse effects on the cardio-respiratory systems of dogs at doses above 0.4 mg/kg, whereas Ani 0.1 mg/kg was devoid of potentially deleterious effects on cardiorespiratory function.

Is oxygen required before atropine administration in organophosphorus or carbamate pesticide poisoning? - A cohort study

Background

Early and adequate atropine administration in organophosphorus (OP) or carbamate insecticide poisoning improves outcome. However, some authors advise that oxygen must be given before atropine due to the risk of inducing ventricular dysrhythmias in hypoxic patients. Because oxygen is frequently unavailable in district hospitals of rural Asia, where the majority of patients with insecticide poisoning present, this guidance has significant implications for patient care. The published evidence for this advice is weak. We therefore performed a patient cohort analysis to look for early cardiac deaths in patients poisoned by anticholinesterase pesticides.

Methods

We analysed a prospective Sri Lankan cohort of OP or carbamate-poisoned patients treated with early atropine without the benefit of oxygen for evidence of early deaths. The incidence of fatal primary cardiac arrests within 3 h of admission was used as a sensitive (but non-specific) marker of possible ventricular dysrhythmias.

Results

The cohort consisted of 1957 patients. The incidence of a primary cardiac death within 3 h of atropine administration was 4 (0.2%) of 1957 patients. The majority of deaths occurred at a later time point from respiratory complications of poisoning.

Conclusion

We found no evidence of a high number of early deaths in an observational study of 1957 patients routinely given atropine before oxygen that might support guidance that oxygen must be given before atropine. The published literature indicates that early and rapid administration of atropine during resuscitation is life-saving. Therefore, whether oxygen is available or not, early atropinisation of OP- and carbamate-poisoned patients should be performed.

Sugammadex: a novel agent for the reversal of neuromuscular blockade

To achieve spontaneous ventilation after completion of surgery, the nondepolarizing effects on skeletal muscle relaxation are often reversed by administration of an acetylcholinesterase inhibitor. However, these agents increase acetylcholine at both the neuromuscular junction and the muscarinic receptors. Therefore, coadministration of an anticholinergic agent is required to prevent parasympathetic adverse effects. In addition, a relative pharmacologic ceiling effect is seen with inhibition of acetylcholinesterase, necessitating some recovery of neuromuscular function before an acetylcholinesterase inhibitor is administered. Sugammadex is a new modified gamma-cyclodextrin compound under clinical investigation in the United States. It does not interact with cholinergic mechanisms to elicit reversal. Instead, it is a selective relaxant binding agent and acts by forming a 1:1 complex with steroidal nondepolarizing neuromuscular blockers in the plasma, lowering the effective concentration available at the receptor. Due to its selectivity, sugammadex does not inhibit the effects of nondepolarizing agents of the benzylisoquinolinium class. In contrast to acetylcholinesterase inhibition, sugammadex is effective even when administered during profound blockade, and it does not require coadministration of an anticholinergic agent. It provides a novel mechanism of action for reversal of the neuromuscular block induced by nondepolarizing aminosteroidal agents.

Impact of atropine injection on heart rate response during treadmill exercise echocardiography: a double-blind randomized pilot study

We evaluated the effect of atropine on the heart rate (HR) response during treadmill exercise echocardiography. A potential limitation of treadmill exercise echocardiography is the requirement for postexercise imaging. Rapid recovery of HR and wall motion abnormalities may decrease test sensitivity. A double-blind randomized study was performed at a tertiary care center. Fifty-two patients (age, 63 +/- 9 years) with known or suspected coronary artery disease were injected with either 0.5 mg of atropine or saline before treadmill exercise echocardiography. HR response during and after exercise was recorded. Atropine resulted in a greater increase in HR before exercise (increase of 15 +/- 9 vs 5 +/- 7 beats per minute, P < 0.0001) and a higher HR rate during the first 5 minutes of exercise (P < 0.05). In recovery, there was an exponential decrease in HR in both atropine and control groups. However, at the end of image acquisition (66 +/- 15 seconds), the HR was higher in the atropine group (128 +/- 21 vs 115 +/- 19 beats per minute, P = 0.02) and remained higher throughout the 10-minute recovery period (P = 0.0015). Dry mouth was more common after atropine injection (P = 0.005); other side effects were similar. The extent and resolution of myocardial ischemia were comparable in both groups. Atropine injection before treadmill exercise echocardiography results in a higher HR during the acquisition of echocardiographic images; whether atropine could affect the diagnostic accuracy of tread mill exercise echocardiography requires further study.

Acute myocardial infarction complicated by hemodynamically unstable bradyarrhythmia: prehospital and ED treatment with atropine

The purpose of this study was to investigate the therapeutic response to atropine of patients experiencing hemodynamically compromising bradyarrhythmia related to acute myocardial infarction (AMI) in the prehospital (PH) setting and the therapeutic impact of the PH response to atropine on further Emergency Department (ED) care. In addition, the prevalence of AMI in patients presenting with atrioventricular block (AVB) is noted. Retrospective review of PH, emergency department (ED), and hospital records. PH patients, with hemodynamically compromising bradycardia or AVB with evidence of spontaneous circulation, who received atropine as delivered by emergency medical services (EMS) personnel, were used. Urban/suburban fire department-based emergency medical services (EMS) system with on-line medical control serving a population of approximately 1.6 million persons. Hemodynamic instability was defined as the presence of any of the following: ischemic chest pain, dyspnea, syncope, altered mental status, and systolic blood pressure less than 90 mm Hg. Bradycardia was defined as sinus bradycardia, junctional bradycardia, or idioventricular bradycardia (grouped as bradycardia), whereas AVB included first-, second- (types I and II), or third-degree (grouped as AVB). The response that occurred within 1 minute of atropine dosing was recorded as none, partial, complete, or adverse. Comparisons were made between patients with AMI and non-AMI hospital discharge diagnoses. The diagnosis of AMI was confirmed by abnormal elevations in creatinine phosphokinase MB fraction. One hundred seventy-two patients meeting entry criteria were identified. Of these, 131 (76.1%) had complete PH, ED, and hospital records and were used for data analysis. Forty-five patients (34.3%) had a primary hospital discharge diagnosis of AMI; the remaining patients had a non-AMI discharge diagnosis. AMI patients were significantly younger (67 +/- 12 v 73 +/- 13 years, P = .025), were less likely to have a history of heart disease (35.5% v54.7%, P = .038), and were more likely to present with chest pain (68.9% v24.4%, P < .001) or hypotension (60% v37.2%, P = .013) compared with non-AMI patients. Forty-five of 131 patients presented with AVB, of which 25 had a hospital discharge diagnosis of AMI (55.6%). The mean time from first dose of atropine to ED arrival and the total dose of atropine received in the PH setting did not differ between AMI and non-AMI groups (15.2 +/- 7.7 v 16.2 +/- 8.7 minutes, P= .5; and 0.9 +/- 0.49 v 1.0 +/- 0.58 mg, P = .25). The likelihood of achieving normal sinus rhythm in the PH setting did not differ between AMI and non-AMI groups (40% v 18.6%, P = .07). No differences were found between AMI and non-AMI groups in the amount of additional atropine given (1.2 +/- 0.58 v 1.3 +/- 1.1 mg, P = .58) or the use of other resuscitative therapies after ED arrival (isoproterenol, 13.3% v12.8%, P = .93; dopamine, 28.9% v26.7% P = .79; transcutaneous pacing, 26.7% v26.7%, P = .99; transvenous pacing, 8.9% v5.8%, P = .51), with the exception of thrombolytic therapy (24.4% v 0%, P< .001) and cardiac catheterization (22.2% v3.4%, P = .001). Despite a lack of significant difference in achieving a normal sinus rhythm in the prehospital or ED setting, AMI patients were more likely to achieve a normal sinus rhythm over the total course of PH and ED care than non-AMI patients (44.4% v24.4%, P = .019). Hemodynamically unstable (by ACLS criterion) AVB presenting in the PH setting is associated with a hospital diagnosis of AMI in most (55.6%) patients in this study. AMI patients with hemodynamically unstable AVB or bradycardia are no more likely to respond to atropine therapy in the PH setting than patients with non-AMI hospital diagnoses. Finally, although there is no difference in the treatment of compromising AVB or bradycardia received by AMI versus non-AMI patients in the PH or ED setting, AMI patients are more likely to achieve a normal sinus rhythm over the t

The efficacy of atropine in the treatment of hemodynamically unstable bradycardia and atrioventricular block: prehospital and emergency department considerations

OBJECTIVE

To determine the efficacy of atropine therapy in patients with hemodynamically compromising bradycardia or atrioventricular block (AVB) in the prehospital and emergency department settings.

METHODS

DESIGN

Retrospective review of prehospital, emergency department, and hospital records.

PARTICIPANTS

Prehospital patients with hemodynamically compromising bradycardia or AVB with evidence of spontaneous circulation who received atropine as delivered by emergency medical services personnel (advanced life support level).

SETTING

Urban/suburban fire department-based emergency medical service system with on-line medical control serving a population of approximately 1.6 million persons.

DEFINITIONS

Hemodynamic instability was defined as the presence of any of the following: ischemic chest pain, dyspnea, syncope, altered mental status, and systolic blood pressure less than 90 mmHg. Bradycardia was defined as sinus bradycardia, junctional bradycardia, or idioventricular bradycardia (grouped as bradycardia) while AVB included first-, second- (types I and II), or third-degree (grouped as AVB). The response that occurred within one minute following each dose of atropine was defined as none, partial, complete, or adverse.

MAIN RESULTS

Of 172 patients meeting entry criterion complete data was available for 131 (76.1%) and constitutes the study population. The mean age was 71 years. Fifty-one percent were female. Forty-five patients had AVB and 86 bradycardia. Patients with AVB were more likely to have a presenting systolic blood pressure less than 90 mmHg than those with bradycardia. In the 131 patients, responses to atropine were as follows: 26 (19.8%) = partial, 36 (27.5%) = complete, 65 (49.6%) = none, and 4 (2.3%) = adverse. Patients presenting with bradycardia (compared to AVB) more commonly: (1) received a single dose of atropine; (2) a lower total dose of atropine in the prehospital interval; (3) were more likely to arrive in the ED with a normal sinus rhythm; and (4) were less likely to receive additional atropine or isoproterenol in the ED. Those patients who achieved normal sinus rhythm over the total course of care were likely to have achieved that rhythm during the prehospital interval. There was no difference between groups in the likelihood of leaving the ED with a normal sinus rhythm achieved during the ED interval. Acute myocardial infarction was more common in patients presenting with AVB (55.5%) than with bradycardia (23.2%, P = 0.001).

CONCLUSIONS

Approximately one-half of patients who received atropine in the prehospital setting for compromising rhythms had either a partial or complete response to therapy. Adverse responses were uncommon. Those patients who presented with hemodynamically unstable bradycardia to EMS personnel responded more commonly to a single dose and a lower total dose of atropine compared to similar patients with AVB. Those patients who achieve normal sinus rhythm by ED discharge were likely to have achieved it during the prehospital interval.

Potentiating effect of acetylcholine on stimulation by isoproterenol of L-type Ca2+ current and arrhythmogenic triggered activity in guinea pig ventricular myocytes

INTRODUCTION

The objective of this study was to determine whether the effect of isoproterenol (Iso) to increase L-type Ca2+ current [I(Ca(L))] and action potential duration (APD) was potentiated in ventricular myocytes following termination of an exposure of these cells to acetylcholine (ACh), and whether this potentiating effect of ACh could be arrhythmogenic.

METHODS AND RESULTS

Transmembrane currents and potentials of guinea pig isolated ventricular myocytes were measured using the whole cell, patch clamp technique. Stimulation of I(Ca(L)) and prolongation of APD caused by Iso (10 nmol/L) were attenuated in the presence of ACh (10 micromol/L), but were transiently enhanced by 111% +/- 20% and 214% +/- 44%, respectively, following termination of a 2- to 4-minute exposure of myocytes to ACh. No changes were observed in the absence of Iso. Both the amplitude and incidence of Iso-induced transient inward current, afterdepolarizations, and sustained triggered activity were greater immediately after termination of exposure to ACh than before application of ACh.

CONCLUSION

Stimulation by Iso of I(Ca(L)) is transiently enhanced in guinea pig ventricular myocytes following termination of exposure of these cells to ACh. The rebound increase of Iso-stimulated I(Ca(L)) is associated with an increase of APD and induction of arrhythmogenic triggered activity.

Evaluation and management of bradyarrhythmias in the emergency department

Bradyarrhythmias may be due to varied causes, although acute myocardial infarction, hypoxia, sepsis, and hypothermia should be considered. Emergency department therapy consists of treatment of the underlying cause, pharmacologic interventions, and temporary pacing. This article provides a detailed discussion of the causes and treatment of bradyarrhythmias in the emergency department.

Pharmacologic controversies in CPR

Since the 1985 Emergency Cardiac Care Conference, numerous controversies about the pharmacology of CPR have arisen (eg, questions about the pharmacokinetics and pharmacodynamics of drugs during CPR, the optimal vehicle for delivery of medications, and the dose of atropine in brady-asystolic cardiac arrest). This article has three objectives: 1) to critically explore these controversies, 2) to provide recommendations for clinical practice, and 3) to identify areas for future study. The ideal route is one which combines rapid access with quick delivery of drug to the central circulation. Because of hemodynamic changes during CPR, administration of drugs into the central circulation is preferable when compared with peripheral venous injection. Whenever drugs are administered from a peripheral i.v. site, the extremity should be elevated, and a 20-mL bolus of i.v. fluid should be given to facilitate access of the agent to the central circulation. If there is a delay in obtaining venous access, epinephrine, lidocaine, and atropine may be administered through the endotracheal tube at 2.5 times the i.v. dose. When administering these drugs through the endotracheal tube, dilute the drug in 10 mL of saline or water and inject it through a long catheter beyond the tip of the endotracheal tube. Dextrose 5% water is the primary vehicle for drug delivery during CPR. However, the administration of glucose during CPR is controversial because of the potentially detrimental effects of hyperglycemia on neuronal function during periods of ischemia. Data are inconclusive regarding the effects of glucose levels on neurologic outcome following resuscitation. Hyperglycemia may be a marker for prolonged resuscitation with subsequent impairment in insulin release.(ABSTRACT TRUNCATED AT 250 WORDS)

Atropine administration in experimental electromechanical dissociation

Atropine can have a place during cardiopulmonary resuscitation (CPR) in the management of asystole, where parasympathetic influence might be excessive. However, the beneficial effects of atropine in electromechanical dissociation (EMD) have not been clearly demonstrated. The authors studied the effects of atropine in combination with epinephrine on an experimental model of EMD in the closed-chested dog. In 15 pentobarbital-anesthetized, mechanically ventilated dogs (mean weight 20 kg), EMD was induced by ventricular fibrillation followed by an external countershock, and was observed for 2 minutes before CPR was started. After 5 minutes of chest compression using a CPR thumper, either atropine 0.5 mg or D5W was administered, and the same injection was repeated every 5 minutes until recovery. Epinephrine 1 mg was administered in alternans. Each dog was submitted to two successive episodes of CPR, using either atropine or D5W, in a randomized order. Of a total of 28 CPRs, five were successful with chest compression alone. In the treatment groups, 10 of 11 were successful with atropine, but only eight of 12 with D5W (P < .01). The duration of CPR was also significantly shorter when atropine was used (9 minutes 56 seconds +/- 14 seconds versus 12 minutes 08 seconds +/- 43 seconds, P < .001). During the recovery period, atropine-treated animals had higher arterial pressure, heart rate, cardiac output and stroke volume. On this experimental model, the administration of high doses of atropine together with epinephrine enhances the recovery from EMD and results in a better cardiac function during recovery.

Bedside evaluation of sinus bradycardia: usefulness of atropine test in discriminating organic from autonomic involvement of sinus automaticity

In 55 patients with persistent sinus bradycardia who underwent an electrophysiologic study of sinus node, both in the basal state and after autonomic blockade (propranolol, 0.2 mg/kg, and atropine, 0.04 mg/kg), an atropine test (0.02 mg/kg) was performed the following day. The 49 patients in whom sinus rate could be evaluated after atropine were subdivided into two groups--group I, 24 patients (age: 54 +/- 13 years) with normal intrinsic sinus automaticity (normal intrinsic heart rate and intrinsic corrected sinus node recovery time) and group II, 25 patients (age: 62 +/- 9 years) with abnormal intrinsic sinus automaticity. In group I, atropine increased sinus rate from 53.7 +/- 4 to 87.9 +/- 17 bpm (delta %: 65.5 +/- 33) and in group II from 51.6 +/- 5 to 73.9 +/- 14 bpm (delta %: 43.1 +/- 26). The discriminant threshold of sinus rate after atropine and its percent increase, obtained by discriminant analysis, was 80 bpm and +52%, respectively, with a misleading classification of 32% and 36%, respectively. The overall predictive accuracy of sinus rate after atropine was higher than the percent change in sinus rate (73% and 65%, respectively). These data evidence that the atropine test is not very helpful in discriminating between an organic and an autonomic involvement of sinus automaticity in patients with sinus bradycardia.

Cardiopulmonary resuscitation. A current perspective

Cardiopulmonary resuscitation is effective if established early and coupled with specific therapeutic interventions. Most cardiopulmonary arrest is due to ventricular fibrillation and early defibrillation offers the highest probability of success. External cardiac compression alone is inadequate to provide adequate perfusion to vital organs and, therefore, cannot sustain life unless coupled with advanced therapeutic interventions. Many new techniques for increasing flow have been developed, but have not been established clinically. The American Heart Association guidelines for CPR are still valid and are the basis for our current CPR. A practical perspective is presented whereby the therapeutic interventions are pursued systematically in an expeditious and coordinated fashion so that the key interventions are made within the first 10 to 15 minutes of the arrest.

Prognostic significance of field response in out-of-hospital ventricular fibrillation

We reviewed 94 cases of prehospital ventricular fibrillation (VF) to determine aspects of field response that predicted outcome. Only one of 37 patients (3 percent) failing to achieve rhythms other than VF or asystole after the first two defibrillations survived to hospital discharge compared to nine of 57 (16 percent) achieving organized rhythms by this point (p less than 0.05). None of 56 patients failing to achieve pulses prior to transport survived to hospital discharge compared to ten of 38 achieving field pulses (p less than 0.01). However, survival to discharge was not significantly different between patients who developed pulses immediately with their rhythms (5 of 17, 29 percent) and those who were defibrillated into pulseless rhythms but later developed pulses in the field (five of 21, 24 percent). Thus, for prehospital VF, the best field response identifies potential survivors prior to hospital arrival. In addition, the frequent occurrence and potentially favorable outcome of an initially pulseless rhythm necessitates reevaluation of current therapy.

Atropine-induced cardioacceleration in patients on chronic propranolol therapy: comparison with the positive chronotropic effect of isometric exercise

The hemodynamic effects of intravenous atropine administration were examined in 24 patients on chronic propranolol therapy. In the first 13 patients the safety of atropine administration was tested by giving the drug in small increments to a total dose of either 1.2 mg (five patients) or 1.7 mg (eight patients). The heart rate after atropine administration in these patients varied between 57 and 82 bpm and no adverse effects were noted. The other 11 patients received 1.2 mg atropine intravenously with hemodynamic measurements obtained prior to and 3 minutes after administration of the drug. Heart rate increased from 57.5 +/- 8.7 to 72.8 +/- 13.9 bpm, mean pulmonary arterial and left ventricular end-diastolic pressure declined, and cardiac index increased. Total systemic resistance decreased in most of the patients. Isometric exercise performed prior to atropine administration in the same 11 patients accelerated heart rate from 57.4 +/- 8.6 to 68.4 +/- 10.8 bpm. A close correlation, r = 0.909, was demonstrated between the postatropine heart rate and the rate during isometric exercise. It is concluded that atropine in a dose of 1.2 to 1.7 mg may be administered safely in patients on chronic propranolol therapy. Isometric exercise may be useful in unmasking vagal tone in beta-blocked patients.

Ventricular fibrillation after intravenous atropine in a patient with atrioventricular block

A 69-year-old black woman with complete AV block developed ventricular fibrillation following an IV injection of 1 mg of atropine sulphate. After a successful DC countershock, the ECG showed a polymorphous ventricular tachycardia which subsided spontaneously. Cardiac catheterization revealed a small left ventricular diverticulum and normal coronary arteries. This seems to be the first reported case of atropine-induced ventricular fibrillation in a patient with complete AV block. The fact that this occurred without previous change of the ventricular rate suggests that the adverse action of atropine was mediated through a mere vagolytic effect at the ventricular level.

Effects of atropine on diastolic time

Atropine was given intravenously to 10 normal volunteers in increments of 0.01 mg/kg to a total dose of 0.04 mg/kg. This produced an increase in heart rate from 65 +/- 11 to 112 +/- 14 beats/min, a decrease in diastolic time from 534 +/- 131 to 180 +/- 65 msec, and a decrease in percent diastole from 55.6 +/- 5.3% to 32.4 +/- 7.2% (p < 0.001). Administration of isoproterenol in doses that increased heart rate from 69 +/- 9 to 99 +/- 12 beats/min produced a decrease in diastolic time from 485 +/- 98 to 312 +/- 47 msec and only a slight decrease in percent diastole, from 54.2 +/- 4.3% to 50.6 +/- 3.9%. Atropine, in doses commonly used clinically, may significantly reduce diastolic time and the percent diastole. Because diastolic time is an important determinant of coronary perfusion, administration of atropine to patients with coronary artery disease may increase myocardial ischemia.