Telemetry of Intracardiac Electrograms: Applications in Spontaneous and Induced Arrhythmias (original) (raw)

Digital Signal Processing Chip Implementation for Detection and Analysis of Intracardiac Electrograms

Pacing and Clinical Electrophysiology, 1994

ET AL.: Digital Signal Processing Chip Implementation for Detection and Analysis of Intracardiac Electrograms. The adoption of digital signal processing (DSP) microchips for detection and analysis of electrocardiographic signals offers a means for increased computational speed and the opportunity for design of customized architecture to address real-time requirements. A system using the Motorola 56001 DSP chip has been designed to realize cycle-by-cycle detection (triggering) and waveform analysis using a time-domain template matching technique, correlation waveform analysis (CWA). The system digitally samples an electrocardiographic signal at 1000 Hz, incorporates an adaptive trigger for detection of cardiac events, and classifies each waveform as normal or abnormal. Ten paired sets of single-chamber bipolar intracardiac electrograms (1 -500 Hz) were processed with each pair containing a sinus rhythm (SR) passage and a corresponding arrhythmia segment from the same patient. Four of ten paired sets contained in traatrial electrograms that exhibited retrograde atrial conduction during ventricular pacing; the remaining six paired sets of intraventricular electrograms consisted of either ventricular tachycardia (4) or paced ventricular rhythm (2). Of 2,978 depolarizations in the test set, the adaptive trigger failed to detect 6 (99.8% detection sensitivity) and had 11 false triggers (90.6% specificity). Using patient dependent thresholds for CWA to classify waveforms, the program correctly identified 1,175 of 1 ,I 97 (98.2% specificity) sin us rhythm depolarizations and 1,771 of 1,781 (99.4 % sensitivity) abnormal depolarizations. From the results, the algorithm appears to hold potential for applications such as realtime monitoring of electrophysiology studies or detection and classification of tachycardias in implantable antitachycardia devices. (PACE 1994; 17:1373-1379 arrhythmia, intracardiac electrogram, antitachycardia device, implantable defibrillator " This work was partially supported by National Science Foun-(Halter) monitoring. The method choice in these dation Grants BCS-8909042 and EID-9023514. applications converged in the late 1970s to a point-Address for reprints: Chih-ming J Chiang. Ph.D.. Telectmnics bypoint comparison of each digitized waveform Pacing Systems, 7400 S. Tucson Way, Englewood, CO 80112. Fax: (303) 799-2213.

Evaluation of Outpatient Arrhythmias and Pacemakers Utilizing Transtelephonic Monitoring Devices

Annals of Noninvasive Electrocardiology, 1996

Background: The purpose of this trial was to evaluate a patient actuated transtelephonic cardiac monitoring system in order to document cardiac arrhythmias and cardiac pacemaker function. Material: Eighty-two patients were prospectively evaluated, 69 with pacemaker (group I) and 1 3 with symptomatic arrhythmias (group 11). Two different recorders were used: a memory loop-recorder (KH) and a wrist-worn recorder (HW). Both of them were implemented using a small, portable, battery-powered transmitter, which monitors a modified V5 in K H and a lead 1 with the HW over regular nondigital pulse telephone lines. Results: In group I, 54 patients used single chamber pacemakers, 2 VDDR, and 13 used dual chamber devices. In group II, all patients included referred palpitations as their symptom. In group I, 248 registers were made using the KH and 50 with the HW. Recordings were made with KH had a 96% accuracy in the diagnosis of the ECG, while HW recordings failed to detect the QRS and the spike in 52% of the cases. Arrhythmia patients (group II) made 65 recordings with KH, all symptomatic: 28 were ventricular ectopic beats (23 isolated, 4 bigeminy, and 1 coupled ventricular ectopic beats); 9 supraventricular ectopic beats (isolated); 18 episodes of sinus tachycardia; and 10 normal sinus rhythm. Artifact was present partially in 6 other recordings, but did not affect the diagnosis. Two patients made no recordings and were excluded from the trial (group I). Conclusions: The loop-recording transtelephonic monitoring system is an excellent tool for the evaluation of patients with symptomatic arrhythmias and pacemaker. The memory KH had an excellent performance, even over regular telephone lines. The accuracy of the H W recordings was low and failed to evaluate the QRS, probably due to the direction of the AQRS vector. A.N.E. 1(3):301-305 transtelephonic monitoring devices; arrhythmias; pacemakers

Computer Quantitated Evaluation of Cardiac Arrhythmias

Pacing and Clinical Electrophysiology, 1981

AL.: Computer quantitated evaluation of cardiac arrhythmias. The identification of a cardiac arrhythmia depends on ihe interpretation of both the QRS complexes and the P waves. P wave detection is unreliable and hence automated diagnostic systems are often imperfect. An alternative is a system which detects QRS only and which classifies the QRS events; the physician then has a detailed quantitated QRS analysis to aid in diagnosis. The ATREC system has an analog QRS detector, which suppresses the P wave and the T wave frequencies and feeds a minicomputer (Mitra 15/35} with signals for the RR interval, the QRS duration, and poiarity. The computer classifies these signals as either narrow or wide complexes. The narrow complexes are analyzed for irregular rhythm, bradycardia, pauses, transient or continuous tachycardia, and fibrillation. The wide complexes are classed by their coupling interval, bi-or trigeminy, doublets, or saivos, and the number per hour. The system gives a trend of the 16 beat mean, and the minimum and maximum heart rate. The data is presented on several displays. (PACE, Vol. 4, /anuary-February, 1981} computerized analysis, quantitated evaluation, cardiac arrhythmias

Automatic "Scanning" by Radio-frequency in the Long-Term Electrical Treatment of Arrhythmias

Pacing and Clinical Electrophysiology, 1979

CRITELLI, G., ETAL. Automatic "scanning" by radiofrequency in the long-term electrical treatment of arrhythmias. The use of programmed electrical stimulation in the long-term treatment of re-entry tachycardia offers encouraging perspectives. Among the others proposed, the "scanning" system seems to be the most effective. However, an implantahle stimulator with these features is not yet avaiJabJe and, thus, a temporary external lead is required. These difficulties have been overcome by utilizing radiofrequency to synchronize and stimulate. An impiantabie device was therefore designed which is triggered by the patient and automatically searches the interruption zone of the tachycardia by exploring the R-R cycle. The external transmitter, which can produce one or (wo synchronized impulses, is programmed to scan the R-H cycle with progressive steps of 5 or 10 ms; when tachycardia is interrupted, further stimulation is inhibited. The implanted module connected to an endocavitary lead does not have any power supply and, therefore, is very small. The efficacy of this method has been demonstrated in 4 patients with supraventricular tacycardia (3 with WPW syndrome) resistant to conventional pharmacologic therapy. (PACE, Vol. 2, May-June 1979} refractory arrhythmias; radiofrequency; cardiac pacing; programmed stimulation Electrical cardiac stimulation allows a new approach to the treatment of hyperkinelic arrhythmias resistant to pharmacologic therapy.'"" In particular, possibilities for control of re-entry arrhythmias are offered by programmed stimulation. The efficacy of this method depends upon the possibility of inducing transient refractoriness in the reciprocating circuit responsihle for tachycardia; in turn inhibiting further activation.'"'"'"'''^ However, all systems

Automated analysis of spontaneously occurring arrhythmias by implantable devices

Journal of Electrocardiology, 1994

Real-time automated systems for arrhythmia analysis by implantable antitachycardia devices have been designed to incorporate two-channel rate criteria with intracavitary atrial and ventricular electrogram morphology. Because the power requirements for morphologic analysis substantially limit antitachycardia device longevity, the authors sought to develop an alternative algo-rJithm that relies solely on rate and three newly developed timing features: onset (:median ventricular rate filtering to detect abrupt onset), loss of atrioventricular (AV) sequency (premature ventricular depolarizations), and regularity-multiplicity (minimal median cycle length variation concurrent with integral [n: 1] AV periodicity). This system was assessed using spontaneously occurring arrhythmias in patients undergoing electrophysiology studies. Electrograms were captured on FM tape (1-500 Hz) using bipolar catheters in the high right atrium and the left ventricular apex. In 11 patients, 2 5 distinct arrhythmias were analyzed, which included sinus tachycardia (ST) (1 passage), supraventricular tachycardia (SVT) (6 passages), ventricular tachycardia (VT) with concurrent sinus rhythm (16 passages), VT with concurrent atrial flutter (VT/AF1) (2 passages), and ventricular fibrillation (VF) ( 1 passage). The algorithm correctly diagnosed ~ of I episode of ST, 4 of 6 episodes of SVT, 15 of 16 episodes of VT with concurrent sinus rhythm, 0 of 2 episodes of VT/AF1, and 1 of 1 episode of VF. Ventricular tachycardia episodes were misdiagnosed as SVT because of absence of loss of AV sequency in VT onset (1 episode), presence of multiplicity between VT and AF1 (1 episode), and absence of VT regularity during AF1 (1 episode). Algorithms that are confined to rate and timing features alone are capable of correctly diagnosing most spontaneously occurring tachyarrhythmias. Misdiagnosis of VT may occur, however, despite the integration of multiple timing features.