Cardiac dysrhythmias associated with central nervous system dysfunction

Intracranial pathology is frequently associated with cardiac dysrhythmias, which are sometimes lethal. Stroke, subarachnoid hemorrhage, seizures and head trauma with or without increased intracranial pressure are observed to be accompanied by myocardial damage and by ECG abnormalities, including T-wave changes, shortened P-R interval, prolonged Q-T interval, premature ventricular contractions, ventricular ectopy, sinus bradycardia, ventricular and supraventricular tachycardias. Derangements of autonomic function have been shown to be responsible for these disturbances of rate, rhythm and conduction. The autonomic nervous system receives neural input from various parts of the cerebral cortex, the hypothalamus and the brainstem which are extensively interconnected. Although unequivocal data supporting associations between specific neuropathological conditions or damage to specific structures and the observed dysrhythmias do not exist, some evidence for laterality of function does exist in humans. Tachycardia and pressor responses are more common after stimulation of the right insular cortex and after experimental stimulation of the left vagus which innervates the atrioventricular node and the cardiac conduction system. Bradycardia seems to be more common after stimulation of the left insular cortex or the right vagus nerve which innervate the sinoatrial node.

Assessing pulse deficit

Pulse deficit--the difference between the apical and peripheral pulse rates--can signal an arrhythmia. You'll need to monitor this deficit if your patient's pulse rhythm is irregular.

Routine withholding of digitalis for heart rate below 60 beats per minute: widespread nursing misconceptions

OBJECTIVE

To describe the nursing practice of withholding digitalis solely on the basis of a heart rate less than 60 beats/min and to determine the rationale for this practice.

DESIGN

Non-randomized survey.

SETTING

Five hospitals in a midwestern metropolitan area, ranging from affiliates of a university medical center to a private community-based hospital.

SUBJECTS

Two hundred twelve nurses, 53% from critical care units, 19% from step-down units, and 28% from nonmonitored units).

RESULTS

Eighty-one percent of respondents either withheld digitalis unnecessarily or administered the drug without correctly indicating why they did so. Nurses with CCRN certification were more likely to answer correctly than those who were not certified (p = 0.0001). Categories for incorrect rationale were (1) incorrect understanding of the drug's mechanism of action (46%), (2) deference to physician's decision-making (28%), (3) adherence to hospital policy (18%), and (4) adherence to guidelines taught in nursing school (6%).

CONCLUSIONS

The results document the need to correct widespread misconceptions regarding the mechanism of action for digitalis and subsequent nursing practice.

Full-disclosure monitoring: a concept that will change the way arrhythmias are detected and interpreted in the hospitalized patient

Conventional methods of detecting and documenting arrhythmia in the hospitalized patient are inadequate. A system of full-disclosure monitoring has been expanded from its roots in Holter monitoring to real-time telemetry. This archiving system stores 24 hours of electrocardiogram (ECG) tracing per patient in computer memory and prints 60 minutes (one minute per line, 60 lines per page) of ECG hourly. This technique eliminates the fear of missing ventricular tachycardia, heart block, or automatic implantable cardioverter defibrillator discharges and ensures that onsets and terminations of runs are captured. Documentation is facilitated by the use of a laser printer that makes standard-sized tracings. The retrospective capability of full disclosure monitoring aids in correlating symptoms to ECG changes and serves as a tool for quality control, bed utilization, and research.

Magnesium in congestive heart failure, acute myocardial infarction and dysrhythmias

Magnesium plays an important role in the functioning of the cardiovascular system. A decrease in magnesium has been linked with tachydysrhythmias, increased mortality in patients with congestive heart failure, and increased mortality after an acute myocardial infarction. The research shows that the use of magnesium supplements in these situations may be beneficial for treating and preventing life-threatening conditions. Magnesium supplements can be administered safely either orally or parenterally depending on the situation.

Pediatric critical care nurses' knowledge of cardiac dysrhythmias

OBJECTIVE

To describe pediatric critical care nurses' knowledge of dysrhythmias in critically ill pediatric patients and relate this knowledge level to certain demographic variables (education, nursing experience, certification, supplemental training, area of employment and geographic region of residence).

DESIGN

A descriptive survey.

SETTING

American Association of Critical-Care Nurses' 19 geographic regions of the United States.

PARTICIPANTS

Of 1000 questionnaires mailed to pediatric critical care nurses who were members of the American Association of Critical-Care Nurses in 1991, 356 responses were received (a response rate of 36%).

INTERVENTION

A criterion-referenced, self-administered test regarding pediatric dysrhythmias and a demographic sheet randomly mailed to 1000 pediatric critical care nurses. Test results were analyzed and compared with demographic variables.

RESULTS

The mean total test score was 66%. Significantly higher total test scores and selected subtest scores were demonstrated in relationship to the following variables: increased age; certification in pediatric advanced life support, advanced cardiac life support or adult critical care; increased years of adult critical care experience; advanced dysrhythmia courses and dysrhythmia self-study; and perceived knowledge level above that of the advanced beginner.

CONCLUSIONS

Pediatric critical care nurses' overall knowledge of dysrhythmias was low. Knowledge strengths included recognition of basic and life-threatening dysrhythmias and calculation of basic ECG measurements. Knowledge deficits included importance of sinus bradycardia in the neonate, appropriate intervention for life-threatening dysrhythmias and calculation of an irregular heart rate. These deficits should be considered when planning continuing education programs for pediatric critical care nurses.

The patient with an automatic implantable cardioverter defibrillator

Sudden cardiac death is the leading cause of death in the United States. A relatively new technology used to treat ventricular dysrhythmias that lead to sudden cardiac death is the automatic implantable cardioverter defibrillator. This device uses patches on the heart to deliver an energy current to convert lethal dysrhythmias. The nurse practitioner can expect to encounter these devices when seeing patients for a variety of diagnoses. This article will serve as a resource for clinical management and patient education.

Rhythm disturbances in the patient with pulmonary disease

Many factors contribute to cardiac dysrhythmias in patients with pulmonary disease. The treatments themselves, as well as the clinical state of hypoxemia, can produce rhythm disturbances. A thorough understanding and awareness of the causes and treatments of the dysrhythmias of this patient population will guide the nurse in the delivery of care.

Antiarrhythmic propafenone: improving patient outcomes

Propafenone which is distributed as Rythmol by Knoll Pharmaceuticals (Whippany, New Jersey) is a class IC antiarrhythmic agent approved by the Food and Drug Administration (FDA) for the treatment of patients with life-threatening, malignant ventricular arrhythmias. It is still under investigation for use in patients with non-malignant ventricular arrhythmias, supraventricular arrhythmias, and atrial fibrillation or flutter. This author describes the pharmacokinetics and nurse's role for improving outcomes for patients on propafenone.

An innovative approach to telemetry monitoring

To use staff more effectively on a medical telemetry unit, nurses collaborated with clinical engineers to incorporate a commercially available pocket pager with a dysrhythmia detection system. Nurses carry a pocket pager which beeps and displays the patient's room number when a dysrhythmia is detected. This system eliminates the need for a telemetry monitor watcher and provides nurses with ongoing information about their patients. It also created an annual savings of approximately $130,000.

Management of ventricular arrhythmias: then and now

OBJECTIVE

To review the changing environment of antiarrhythmic therapy.

DATA SOURCES

The majority of articles chosen were written by experts in the field of arrhythmia management. The references include a pilot study, abstracts, original articles and results of study groups. An equal number of sources used in this article were obtained from fellow healthcare professionals and MEDLINE searches.

STUDY SELECTION

Large, controlled clinical trials in which patient populations had structural heart disease, prior myocardial infarction and/or frequent ventricular premature beats. All were treated with either antiarrhythmic therapy or devices.

DATA SYNTHESIS

Past research in the field of arrhythmia management has indicated that ventricular premature beat suppression is the key to increasing patient survival. After reviewing the results of such pivotal trials as the Cardiac Arrhythmia Suppression Trial, however, the question of whether to initiate therapy remains.

CONCLUSIONS

Several trials investigating the efficacy of antiarrhythmic drugs in decreasing sudden death have yielded disappointing results. These trials have been beneficial, however, in classifying arrhythmias and assessing patient risk. The outcomes of these trials, combined with advances in the treatment of heart disease, provide us with a framework for antiarrhythmic therapy. Additional controlled clinical trials are necessary if we are to learn the best means of increasing survival in ventricular arrhythmia patients.

Diagnostic uses of epicardial electrodes after cardiac surgery

Dysrhythmias after cardiac surgery are common. The etiologies and treatments are diverse depending upon the origin of the dysrhythmia. An atrial electrogram obtained from epicardial electrodes temporarily positioned at the time of surgery can detect the origin of an anomalous rhythm. This article discusses the diagnostic use of epicardial atrial electrograms after cardiac surgery, types of atrial electrograms, steps to interpretation, and nursing implications. An understanding of their use can facilitate patient management and therapy.

Taking the mystery out of rhythm interpretation: atrial electrograms

OBJECTIVE

To verify cardiac rhythms in which diagnosis from conventional surface recordings was unclear.

DESIGN

Approximately five electrograms were recorded each week from randomly selected patients who had undergone cardiac surgery in a two-year period from 1989 to 1991.

SETTING

A 1000 bed acute care medical facility that provides care to more than 1300 patients per year after open heart surgery.

PATIENTS

Adult patients in the surgical intensive care unit or stepdown units who were recovering from coronary artery bypass grafting, valve replacement or repair, aneurysm resection, and/or atrial and ventricular septal defect repairs.

RESULTS

The atrial electrogram was used to diagnose various dysrhythmias. The most frequent application was the verification of atrial flutter, atrial fibrillation, and junctional rhythm. Another use was to differentiate between ventricular tachycardia and supraventricular tachycardia with aberrant conduction.

CONCLUSION

Critical care clinicians caring for patients who have undergone cardiac surgery must be proficient at rapid, accurate rhythm interpretation to give appropriate treatment. The use of atrial electrograms can be extremely helpful in rhythm interpretation and clarification for this population of patients.

Antidysrhythmic agents

Antidysrhythmic therapy is used to suppress supraventricular and ventricular dysrhythmias, thus relieving symptoms and reducing the risk of sudden cardiac death. The Cardiac Arrhythmia Suppression Trial (CAST) found an increased mortality rate in a group of patients treated with two antidysrhythmic agents. This result has had a profound impact on the prescribing and monitoring of antidysrhythmic therapy. Prodysrhythmia is a frequent and serious complication of antidysrhythmics and is unpredictable. Assessment of benefit versus risk of drug therapy for each patient is recommended. The nurse's knowledge of antidysrhythmic pharmacology, including symptoms that indicate adverse reactions, and prodysrhythmia influences the patient outcome.

Cardiotoxic side effects associated with tricyclic antidepressant overdose

Tricyclic antidepressants (TCAs) are a popular, effective medication prescribed for patients with depression. The patient with severe depression may exhibit suicidal tendencies; thus, overdose of a prescribed TCA may occur, resulting in a potentially fatal outcome. The cardiotoxic effect of TCA overdose is the most pronounced complication. Multiple rhythm disturbances may occur in the presence of a TCA overdose. The greatest number of adverse cardiac symptoms and electrocardiographic changes are likely to occur within the first 24 hours after overdose. Nursing care of the patient with a TCA overdose is based upon ongoing patient assessment, identification of problems and potential problems, establishment of expected patient outcomes, and specific nursing interventions.

Complex dysrhythmias in infants and children

Dysrhythmias in infants and children are, in many ways, similar to those in adults, yet several important differences exist in their presentation and management. Complex dysrhythmias most frequently encountered in pediatrics include sinus node dysfunction, chaotic atrial rhythm, atrial flutter, supraventricular tachycardia (including Wolff-Parkinson-White syndrome and junctional ectopic tachycardia), complete atrioventricular block (congenital and acquired), and ventricular dysrhythmias (premature ventricular contractions and ventricular tachycardia). Newer approaches to the diagnosis and management of these dysrhythmias are addressed in this paper.

Neurogenic electrocardiographic abnormalities in subarachnoid hemorrhage

ECG abnormalities are a frequent, potentially life-threatening complication of subarachnoid hemorrhage. Yet, the mechanism behind these ECG abnormalities is poorly understood. Nursing literature has given this phenomenon little attention. However, neurogenic ECG abnormalities have implications for critical care nursing practice and research. In this article the most frequently documented neurogenic ECG abnormalities occurring in patients with subarachnoid hemorrhage have been discussed. The proposed pathophysiologic mechanisms and nursing implications were also discussed. Patients with neurogenic ECG abnormalities require complex, multifaceted nursing assessment and intervention. Only with a better understanding of the phenomenon will the critical care nurse be able to meet the needs of these patients.

Nursing management of postoperative dysrhythmias

Clinical decision making about postoperative dysrhythmias requires the specialized skills and knowledge of the critical care nurse. During the immediate postoperative period, the critical care nurse must be aware of physiologic alterations and factors that may predispose the cardiac surgery patient to dysrhythmias. Correction of these physiologic alterations is usually the first step in postoperative dysrhythmia management. Should dysrhythmias develop following cardiac surgery, the critical care nurse may use management options that are not available in other surgical or medical patients. AEGs and pacing to suppress ectopy, to augment cardiac output, or to overdrive tachydysrhythmias are some of the available options. The advent of external, temporary DDD pacing will augment these management options. The challenges presented by these options emphasize the vital role of the critical care nurse in postoperative dysrhythmia management.

Adenosine in the pediatric population: nursing implications

Tachydysrhythmias in the neonatal and pediatric age group can present a challenge to pediatric nurses. A new antiarrhythmic drug, adenosine, has proven useful as an acute tool in the termination and diagnosis of these potentially life-threatening dysrhythmias.

A collaborative teaching model

In the first 4 years of the program, more than 1500 individuals have attended and approximately 90% have successfully completed the course. Because of the success of this program, GCOI is contemplating other collaborative efforts. This model of collaboration could easily be instituted by hospitals in other large cities to provide a high-quality continuing course in a cost-effective and time-efficient manner.

Defibrillation and cardioversion in children

This article overviews the indications for cardioversion or defibrillation by reviewing normal conduction, common arrhythmias, and hemodynamic assessment in children requiring this treatment approach. The procedure for each is outlined in detail.

Clinical decision making of critical care nurses managing computer-simulated tachydysrhythmias

The purposes of this study were to describe the clinical decision making of critical care nurses managing computer-simulated tachydysrhythmias and to assess the major sources of error related to the management of two tachydysrhythmias: atrial flutter and ventricular tachycardia. In this descriptive study, 142 critical care nurses each completed four computerized clinical simulations (two atrial flutter and two ventricular tachycardia). Simulation performance was measured by proficiency score (comparison with expert performance), patient outcome (cure or die), and amount of data collected before the first intervention. Mean proficiency scores were 51% for atrial flutter and 35% for ventricular tachycardia. Thirteen percent of the atrial flutter and 35% of the ventricular tachycardia simulations ended in patient death. Failure to recognize ventricular tachycardia and unfamiliarity with second- and third-line treatments were major sources of error. Medication errors were the cause of death in 87% of the simulations ending in patient death. These results document the need for emphasis on dysrhythmia management in the critical care curriculum.

Ventricular arrhythmia: management guidelines for the primary health care setting

Ventricular arrhythmia is a common problem in the ambulatory setting. Ventricular arrhythmias that appear to be similar on the electrocardiograph may have different prognostic significance, depending on the patient's age and the presence of underlying heart disease or ventricular dysfunction. The ultimate goal in the care of any patient with ventricular arrhythmia is prevention of sudden cardiac death. Patients can usually be classified into one of five diagnostic categories, based on symptoms and evidence of underlying heart disease. This article discusses the classification of ventricular arrhythmias as either benign, potentially malignant or malignant. The risks of antiarrhythmic therapy and specific management plans for each of the five diagnostic categories are provided. These management plans are meant to serve as a framework for the clinician who provides primary care to these patients. An explanation of terms used commonly in the interpretation of ventricular arrhythmias is included, as well as guidelines for the assessment of patients with ventricular arrhythmias.

A primary care approach to cardiac arrhythmias

Cardiac arrhythmias may present in a variety of ways in the primary care setting. They may or may not be accompanied by related symptoms. Rhythm disturbances span the continuum of posing no risk to the patient to being life-threatening. The importance of a thorough history and physical examination to detect the presence of cardiovascular disease or related factors cannot be overemphasized. An ECG is essential for the accurate identification of cardiac arrhythmias. Evaluation and management of cardiac rhythm disturbances often requires collaboration with medical practitioners and possible specialist referral. The primary care nurse practitioner must be able to recognize the important red flags in clinical practice such as cardiac syncope, ischemia, or failure. Finally, an understanding of the diagnostic and therapeutic measures used for arrhythmia evaluation and management will facilitate appropriate patient education, counseling, and follow-up.

The automated implantable cardioverter

The automatic implantable cardioverter defibrillatory (AICD) is becoming the treatment of choice for patients with ventricular tachycardia and ventricular fibrillation. The widespread use of the AICD is requiring nurses in a variety of settings to become familiar with the device and device-patient interactions. This article attempts to define specific issues and nursing interventions relative to the AICD.