Arrhythmias diagnosis

Make a firm diagnosis. A firm arrhythmia diagnosis should be established. For example, the misuse of verapamil in patients with ventricular tachycardia mistakenly diagnosed as supraventricular tachycardia can lead to catastrophic hypotension and cardiac arrest. As increasingly sophisticated methods to characterize underlying arrhythmia mechanisms become available and are validated, it may be possible to direct certain drugs toward specific arrhythmia mechanisms. 

Gladstone PJ, Duxbury GB, Berman ND, Arrhythmia diagnosis by electrogram telemetry Involvement of dual chamber pacemaker. Chest 1987 91 115-116. 

Arrhythmia—diagnosis—Handbooks. 4. Arrhythmia—diagnosis—Nurses Instruction. 5. Heart Diseases—diagnosis—Handbooks. 6. 

To reduce mortality, administration of an aldosterone antagonist, either eplerenone or spironolactone, should be considered within the first 2 weeks following MI in all patients who are already receiving an ACE inhibitor (or ARB) and have an EF of equal to or less than 40% and either heart failure symptoms or diagnosis of diabetes mellitus.3 Aldosterone plays an important role in heart failure and in MI because it promotes vascular and myocardial fibrosis, endothelial dysfunction, hypertension, left ventricular hypertrophy, sodium retention, potassium and magnesium loss, and arrhythmias. Aldosterone antagonists have been shown in experimental and human studies to attenuate these adverse effects.70 Spironolactone decreases all-cause mortality in patients with stable, severe heart failure.71... 

Diagnosis of torsades de pointes requires examination of the arrhythmia on ECG. 

O Determining a correct and accurate diagnosis is essential prior to any consideration of pharmacotherapy. When a patient complains of paroxysmal, stereotypical spells that may be seizures, it must be determined if the spells are really seizures. Numerous other disorders, including syncope, psychogenic nonepileptic events (i.e., pseudoseizures), anxiety attacks, cardiac arrhythmias, hypoglycemia, transient ischemic... 

Rapid diagnosis of cardiopulmonary arrest is vital to the success of CPR. Patients must receive early intervention to prevent cardiac rhythms from degenerating into less treatable arrhythmias. 

Plasma steady-state levels of up to 10 /ig/ml are occasionally necessary for control of ventricular arrhythmias but cannot always be tolerated without serious toxic effects. Of thirteen patients referred to a specialist coronary care unit because of reputed refractoriness to the therapeutic effect of lignocaine, in only four was the diagnosis substantiated by demonstrating failure of therapeutic response to blood lignocaine concentrations in excess of 10 /tg/ml (H8). In four patients a therapeutic response was observed at blood lignocaine levels between 5 and 10 /xg/ml, and another five patients were responsive to lignocaine blood levels within the usual therapeutic range. 

Optimal therapy of cardiac arrhythmias requires documentation, accurate diagnosis, and modification of precipitating causes, and if indicated, proper selection and use of antiarrhythmic drugs. These drugs are classified according to their effects on the action potential of cardiac cells and their presumed mechanism of action. 

Bauce, B., Rampazzo, A., Basso, C., Bagattin, A., Daliento, L., Tiso, N., Turrini, P., Thiene, G., Danieli, G. A., and Nava, A. (2002). Screening for Ryanodine Receptor Type 2 Mutations in Families with Effort-Induced Polymorphic Ventricular Arrhythmias and Sudden Death Early Diagnosis of Asymptomatic Carriers. J Am Coll Cardiol 40(2) 341—9. 

A 43-year-old woman developed high blood pressure and her doctor thought the diagnosis was diabetes. Her blood pressure kept increasing steadily until she developed cardiac arrhythmias and partial blindness. She was then sent to a university hospital, where a tumor on the adrenal gland was discovered. The tumor was removed, and she recovered completely. Answer the following ... 

In contrast to phenoxybenzamine, phentolamine [fen TOLE a meen] produces a competitive block of ai and a2 receptors. The drug s action lasts for approximately 4 hours after a single administration. Like phenoxybenzamine, it produces postural hypotension and causes epinephrine reversal. Phentolamine had been used in the diagnosis of pheochromocytoma and in other clinical situations associated with excess release of catecholamines. Phentolamine-induced reflex cardiac stimulation and tachycardia are mediated by the baroreceptor reflex and by blocking the a2 receptors of the cardiac sympathetic nerves. The drug can also trigger arrhythmias and anginal pain and is contraindicated in patients with decreased coronary perfusion. 

Doctors and drugs interfere with cardiac electro-physiological actions at their peril. In emergencies, action often needs to be taken by the most junior doctor in the team, and some rote recommendations are then necessary. The diagnosis and elective treatment of chronic, or episodic arrhythmias require greater skill to ensure that the correct balance between risk and benefit is achieved. As will become clear. 

Adenosine is the treatment of choice for diagnosis and reversal of supraventricular arrhythmias. Verapamil is an alternative for the management of narrow complex tachycardias. Amiodarone is the most effective drug at reversing atrial fibrillation, and in prevention of ventricular arrhythmias, but has several adverse effects. 

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