USEFULNESS OF ATRIAL ELECTROGRAMS RECORDED VIA CENTRAL VENOUS CATHETERS IN THE DIAGNOSIS OF COMPLEX CARDIAC-ARRHYTHMIAS

Objective: To assess the role of intravascular atrial electrograms in improving the diagnosis of complex cardiac arrhythmias in critically i ll patients. Design: Prospective, clinical study comparing the accurac y of cardiac rhythm diagnosis using standard surface electrocardiogram (EKG) and intravascular atrial electrograms. Setting. Intensive care unit of a university teaching hospital. Patients: A total of 57 critic ally ill patients (44 cardiothoracic surgery, five acute myocardial in farction, two septic shock, six miscellaneous) with 85 complex cardiac arrhythmias that were unable to be diagnosed with certainty using the surface EKG. Interventions: None. Measurements and Main Results: The intravascular atrial electrogram altered diagnosis based on the surfac e EKG in 11 (13%) patients and confirmed rhythm diagnosis in 60 (71%) of 85 patients with arrhythmia. Of 61 patients with wide complex tachy cardia, 40 (66%) were diagnosed as ventricular tachycardia (atrioventr icular dissociation demonstrated on the atrial electrogram), and 11 (1 8%) as supraventricular tachycardia with aberrant conduction. Ten (16% ) wide complex tachycardias could not be diagnosed with confidence usi ng both surface EKG and intravascular electrogram. There were no adver se effects with this technique. Conclusions: Intravascular atrial elec trograms recorded via central venous catheters are useful in the diagn osis of complex cardiac arrhythmias, particularly ventricular tachycar dia. The technique is safe, simple, and quick.