[Arrhythmic symptoms and events in patients wearing an implantable automatic defibrillator]

Although symptoms can be of some help in identifying the arrhythmia related to implantable cardioverter-defibrillator (ICD) discharge, symptomatic supraventricular arrhythmias and asymptomatic ventricular tachycardia have been reported.

In 18 survivors of cardiac arrest implanted with an ICD, the symptoms and intracardiac electrograms were systematically evaluated, in order to better define a relationship between some symptoms and supraventricular or ventricular tachyarrhythmias.

A total number of 249 arrhythmic episodes were detected by the ICD during a mean follow-up of 378 +/- 107 days (range 137 to 642). Within this time, in 15 out of 18 patients (83%) at least one arrhythmic event alerting the device occurred, determining a therapeutic attempt in 13 patients. Only 49% of the episode stored by the ICD were symptomatic. Symptoms like palpitations, dizziness, "going under" lacked of predictability for ventricular tachycardia; in contrast, patients describing a "hot flush", alone or associated with palpitations, lightheadedness, dizziness most commonly recognized a ventricular tachyarrhythmias. This symptom had a good sensitivity (72%) and a high specificity (95%) in detecting a sustained ventricular tachycardia.

Since in most cases symptoms are not a reliable criterion for validating ICD discharges stored electrograms during ICD activation need to be considered for analysis. However, the data of this study showed the importance of "hot flush" as a key symptom for recognizing the occurrence of a sustained ventricular tachyarrhythmia.