Arrhythmias goals

Cardiac arrhythmias are an important cause of morbidity and mortality approximately 400,000 people per year die from myocardial infarctions (MI) in the United States alone. Individuals with MI exhibit some form of dysrhythmia within 48 h. Post-mortem examinations of MI victims indicate that many die in spite of the fact that the mass of ventricular muscle deprived of its blood supply is often quite small. These data suggest that the cause of death is ventricular fibrillation and that the immediate availability of a safe and efficacious antiarrhythmic agent could have prolonged a number of Hves. The goals of antiarrhythmic therapy are to reduce the incidence of sudden death and to alleviate the symptoms of arrhythmias, such as palpitations and syncope. Several excellent reviews of the mechanisms of arrhythmias and the pharmacology of antiarrhythmic agents have been pubflshed (1,2). 

The risk of atrial flutter is a 2 1 transmission to the ventricles generating a high ventricular rate. The therapeutic goal is to reduce transmission to 3 1 or 4 1 by administration of either (3-adrenoceptor antagonists, Ca2+ channel blockers or amiodarone. Quinidine must not be used in this arrhythmia, since it accelerates AV-conduction due to its vagolytic effect. 

The most common arrhythmia in humans is atrial fibrillation. Because of the lack of rhythmic atrial activation, irregular ventricular rhythms and thromboembolism result. There are two possible therapeutic goals ... 

An arrhythmia may occur as a result of heart disease or from a disorder that affects cardiovascular function. Conditions such as emotional stress, hypoxia, and electrolyte imbalance also may trigger an arrhythmia An electrocardiogram (ECG) provides a record of the electrical activity of the heart. Careful interpretation of the ECG along with a thorough physical assessment is necessary to determine the cause and type of arrhythmia The goal of antiarrhythmic drug therapy is to restore normal cardiac function and to prevent life-threatening arrhythmias. 

The treatment goals for acute intoxication of ethanol, cocaine/amphetamines, and opioids include (1) management of psychological manifestations of intoxication, such as aggression, hostility, or psychosis, and (2) management of medical manifestations of intoxication such as respiratory depression, hyperthermia, hypertension, cardiac arrhythmias, or stroke. 

The desired outcome depends on the underlying arrhythmia. For example, the ultimate treatment goals of treating AF or atrial flutter are restoring sinus rhythm, preventing thromboembolic complications, and preventing further recurrences. 

The short-term goals of therapy for IHD are to reduce or prevent anginal symptoms that limit exercise capability and impair quality of life. Longterm goals are to prevent CHD events such as MI, arrhythmias, and heart failure and to extend the patient s life. 

Management of hypothyroidism consists of identifying the underlying cause and then providing thyroid hormone replacement to normalize thyroid sta-ms. The goal of treatment is to reduce semm TSH levels to normal, which for most assays is roughly between 0.5 and 3 mU/1. Oversuppression of TSH levels is probably not advisable, as overtreatment may predispose to cardiac arrhythmias (particularly atrial fibrillation), and may have subtle effects on bone mineral density. 

Arrhythmias are caused by abnormal pacemaker activity or abnormal impulse propagation. Thus, the aim of therapy of the arrhythmias is to reduce ectopic pacemaker activity and modify conduction or refractoriness in reentry circuits to disable circus movement. The major mechanisms currently available for accomplishing these goals are (1) sodium channel blockade, (2) blockade of sympathetic autonomic effects in the heart, (3) prolongation of the effective refractory period, and (4) calcium channel blockade. 

Several treatment options are available when confronted with AF dependent on its clinical effect and duration. The hemodynamic effects and/or cardiac ischemia due to a rapid ventricular rate can seriously complicate a catheter procedure and can even be life threatening in some instances, Therefore, one goal can be to alleviate the clinical repercussions of the arrhythmia in order to finalize the procedure. The second goal is to restore sinus rhythm if possible. To achieve the first goal, a strategy called "rate control" might be sufficient if allowed by the hemodynamic... 

The CRO should evaluate the feasibility of the sponsor s study plan. If the sponsor has provided detailed study specifications and the CRO is experienced in the target therapeutic area, it will be possible for the CRO to compare its past experiences with the sponsor s projections and to identify any inconsistencies. If the CRO believes it cannot achieve the sponsor s expectation (e.g. enroll three patients/month at each site in an arrhythmia study), it is important to bring it to the sponsor s attention and negotiate a more realistic goal. 

It was inappropriate to attempt to improve on quinidine as an anti-arrhythmic drug until there was some reliable information on its mechanism of action. This could not be obtained until there was an understanding of the mechanisms responsible for the production of arrhythmias in diseased hearts, and the techniques and information necessary for this understanding still are insufficient. To be more specific, it was incorrect to identify the need to treat cardiac arrhythmias or even a specific disturbance of rhythm as a problem and equally incorrect to set the search for a compound exerting some but not all of the actions of quinidine as a goal. ... 

Patients with chronic atrial fibrillation—a common supraventricular arrhythmia—routinely receive warfarin to prevent the development of blood clots in the poorly contracting atrium and to decrease the risk of embolism of such clots to the brain or other tissues. Such patients are also often treated with anti arrhythmic drugs. The primary goals of antiarrhythmic treatment are to slow the atrial rate and, most importantly, control the ventricular rate. 

My goal as editor-in-chief of the Fundamental and Clinical Cardiology series is to assemble the talents of world-renowned authorities to discuss virtually every area of cardiovascular medicine. In the current monograph, Drs. Harold L. Dauerman and Burton E. Sobel have edited a much-needed and timely book. Future contributions to this series will include books on molecular biology, interventional cardiology, and clinical management of such problems as coronary artery disease and ventricular arrhythmias. 

Goal Provide patients with an adequate dose of the drug to prevent recurrence of their arrhythmia, while minimizing the incidence of adverse effects. Clinical considerations include the following evaluations ... 

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