TRANSTELEPHONIC MONITORING AND TRANSMISSION OF STORED ARRHYTHMIA DETECTION AND THERAPY DATA FROM AN IMPLANTABLE CARDIOVERTER-DEFIBRILLATOR

A new transtelephonic monitoring device designed for use with implanta ble cardioverter defibrillators (ICDs) was evaluated. It is capable of interrogating ICDs and transmitting the following data via telephone: programmed parameters (e.g., ventricular tachycardia [VT] and ventric ular fibrillation [VF] detection, therapies), number of VT and VF epis odes, identification of successful therapies, the 20 cycle lengths pre ceding the last episode detected, the 10 cycle lengths after the last delivered therapy, battery voltage, and real-time transmission of the patient's rhythm. Eighteen patients (mean age 64 +/- 17 years; 15 male s) were implanted with an ICD and epicardial lead system. The patients who did not live near the primary hospital were provided with this tr ansmitter and instructed to transmit monthly and whenever presyncope, syncope, or a shock were experienced. zFive hundred ten episodes of sp ontaneous arrhythmia (495 VT, 15 VF) were detected in 14 of 18 patient s in a 24-month period and She success of each therapy (antitachycardi a pacing, cardioversion 0.4-34 J, defibrillation 34 J) was analyzed. T he number of therapies delivered and their success (%) in terminating the arrhythmia were: 380 ramp/86%, 116 burst/84%, 119 cardioversion/57 %, and 15 defibrillations/100% Sixty-three (42%) of the 152 transmissi ons indicated an arrhythmia. Twenty-five (16%) of the 152 were transmi tted because of symptoms. Sixteen (9.7%) of 165 VT episodes could not be terminated by the full set of programmed VT therapies. Analysis of the pre- and post-episode intervals along with the patient's transmitt ed rhythm indicated that sinus tachycardia or atrial fibrillation were likely responsible for these episodes. The transmitted data included the real-time ECG, which provided acute rhythm status plus stored data from the ICDs memory identifying the chronic arrhythmias detected, th e therapies delivered, and the number and type of successful and ineff ective therapies. This information provided the clinical data to the p rimary physician in order to determine the effectiveness of the progra mmed detection and therapy parameters and in some cases recommend to t he home physician modifications to the device parameters or medication adjustments for enhanced arrhythmia control. We conclude that telepho ne transmission of stored ICD data is feasible and useful for patient management. It may obviate the need for patients experiencing symptoms to return to a site capable of device interrogation.