Biomedical subjects

R M Luceri

Publications and source records attributed to R M Luceri.

At least 19 recordsLinked to original sources

PubMed1995

Initial clinical experience with a dual lead endocardial defibrillation system with atrial pace/sense capability. United States and Canada Enguard Investigations.

Ninety-three patients underwent implants of the Telectronics Model 4211 ICD attached to the Enguard PFX endocardial defibrillation lead system. Eighty-one males and 12 females ranging in age from 25-85 years (mean = 64). Coronary disease was the substrate in the majority (88%); mean left ventricular ejection fraction was 30%. VT was present in 66%, VF in 22%, and both in 7%. Three lead configurations were used in the study: ventriculo-atrial (U1, 86%); bidirectional (B2, 12%); and ventricular to patch (U2, 2%). Mean RV pacing thresholds were 0.46 V pre- and 0.54 V posttesting, with no significant differences between the two. Mean R wave voltage was 11.05 mV pre- and 11.72 mV posttesting, also not significantly different. A subgroup of 13 patients had mean atrial pacing thresholds of 0.59 V at 0.5 msec pulse width, with mean P waves of 4.01 mV. Mean defibrillation threshold for the entire group was 10.6 J using biphasic waveforms. Defibrillation thresholds by configuration were: 399 V (U1); 475 V (U2); and 350 V (B2). All patients but one had thresholds < 550 V in at least one configuration. The 4211/Enguard system was implanted without (86%) or with (14%) a subcutaneous patch electrode. Early postoperative findings related to the ICD system include: one device circuit failure, one early lead dislodgement, and one pacing exist block.(ABSTRACT TRUNCATED AT 250 WORDS)

Defibrillators, Implantable↗

PubMed1995

Cost and length of hospital stay: comparisons between nonthoracotomy and epicardial techniques in patients receiving implantable cardioverter defibrillators.

Twenty-five patients with implantable cardioverter defibrillators (ICDs) implanted intrathoracically (group I) were compared with 25 patients who underwent implant using the nonthoracotomy approach (group II). All systems were implanted by the same medical team, in the same high volume implanting center. Indications for implantation were comparable in both groups. Patient characteristics were not statistically different with the exception of age (66-group I vs 71-group II; P < 0.05). Although left ventricular ejection fractions appeared to differ (32% vs 37%, respectively), this difference was not statistically significant (P = 0.06). ICD models used in group I were: Ventritex Cadence (16), Telectronics Guardian 4211 (2), Medtronic PCD (7); in group II they were: Ventritex Cadence (15), Guardian 4211 (2), and CPI 1600 (1). Total length of hospital stay was 16 +/- 6 days for group I versus 12 +/- 5 for group II (P < 0.05). Number of postoperative days in an intensive care unit was 3.2 +/- 2.8 for group I versus 0.5 +/- 0.6 for group II (P < 0.0001). Postoperative length of stay was 8.2 +/- 3.1 for group I versus 5.7 +/- 4.4 for group II (P < 0.001). Mean total hospital charges for the entire length of stay were $72,918 +/- $26,770 in group I versus $55,031 +/- $42,870 in group II, representing a mean reduction of 21% in global costs for group II patients. These data confirm that nonthoracotomy ICD implantation in an experienced center is associated with significantly shorter hospital stays, a virtual elimination of the need for postoperative intensive care, and globally lower total hospital costs. In addition, the presence of a statistically older population in group II does not negate these beneficial effects.

Aged↗

PubMed1994

Simplified subxiphoid placement of implantable cardioverter defibrillators using a posterior rectus pocket.

A simplified subxiphoid procedure using a single longitudinal epigastric incision and posterior rectus pocket for implantable cardioverter defibrillators was used in 100 patients. Through a single incision, ventricular patches are placed via a transverse pericardiotomy, and a pouch is created behind the rectus abdominis muscle in the left upper quadrant for placement of the implantable cardioverter defibrillator. Patients have minimal discomfort soon after operation, and the implantable cardioverter defibrillator generator is imperceptible to most.

Defibrillators, Implantable↗

PubMed1993

Changing trends in therapy delivery with a third generation noncommitted implantable defibrillator: results of a large single center clinical trial.

Thirty-four patients underwent implantation of a third generation ICD, the 4210 ATP, for sudden cardiac death or ventricular tachycardia. This device incorporates significant telemetry logs as well as a detailed analysis of each arrhythmia episode detected. During the period of clinical follow-up, a mean of 12.2 months, a total of 26,569 VT or VF detections were made. The vast majority of these were either due to atrial fibrillation, nonsustained VT, or "noise" detection, and only 6% led to device therapy. ATP was successful in 86.3% of episodes, with 3.5% accelerations and 2.4% failure of ATP trains. The majority of inappropriate therapy episodes were clustered in seven patients, and all were easily diagnosed with the aid of the extensive telemetry logs and sense histories. Of five late deaths, three were from congestive heart failure, one from cerebrovascular accident, and one unknown. These data reveal that this "tiered" therapy noncommitted ICD performs to expectations; the stored data is of significant value in diagnosing the cause of ICD therapy. In addition, ATP is an effective modality for termination of VT.

Aged↗

PubMed1991

Improved patient surveillance and data acquisition with a third generation implantable cardioverter defibrillator.

Thirteen patients were implanted with the Telectronics 4210 ATP implantable cardioverter defibrillator (ICD) for ventricular tachycardia or ventricular fibrillation. This device has multiprogrammable antitachycardia pacing, bradycardia pacing, and shock therapies. In addition, there is extensive data logging and ECG snapshot capability for arrhythmia confirmation and response to therapy. These features permit easy retrieval of all detected and treated events, whatever the eventual outcome. In this study, the data logged at predischarge electrophysiological testing was compared to the data recorded in a standard manner. The bulk of the data, however, was derived from long-term follow-up of spontaneous events over a mean period of 203 days (range 154-257). During this period, a total of 6,193 arrhythmia detections were made: 20 were classified as ventricular fibrillation, and 6,173 as ventricular tachycardia. The vast majority of these (93%) terminated spontaneously without ICD intervention (5,738), underscoring the benefit of a standard second confirmation prior to therapy delivery (noncommitted system). There were 394 arrhythmia episodes treated with antitachycardia pacing; of these a total of 8.3% accelerated to either more rapid ventricular tachycardia or ventricular fibrillation (4.3% and 4.0%, respectively). Events were reported in an "episode log" format, listing all arrhythmia detections with time/date annotation; or in a "sense history" format, detailing each episode from start to conclusion. These data demonstrate that this advanced, "tiered" ICD with data recall contributes to better patient management, and permits a more tailored termination prescription for the individual patient.

Cardiac Pacing, Artificial↗

PubMed1991

Clinical electrophysiological effects of intravenous recainam: an antiarrhythmic drug under investigation for the treatment of ventricular and supraventricular arrhythmias.

This open-label, multicenter study was designed to assess the electrophysiological properties of intravenous recainam, an investigational Class I antiarrhythmic agent. In 25 patients undergoing electrophysiological studies for the evaluation of arrhythmias, recainam was administered intravenously in a loading infusion (0.1 mg/kg/min) for 40 minutes, followed by a maintenance infusion (0.02 mg/kg/min) until the completion of the study. Electrophysiological measurements were obtained at baseline, 30 minutes after initiation of the loading infusion, and 30 minutes after termination of the infusion during washout. Conduction intervals, refractory periods, and sinus node recovery times were measured during sinus rhythm and during atrial or ventricular pacing. Vital signs were obtained and recorded before, during, and after recainam infusion. The results showed no change in mean arterial pressure, but heart rate increased slightly by 4 beats/min following recainam infusion. Recainam produced a generalized slowing of intracardiac conduction. The mean intraatrial conduction time, measured at an atrial paced cycle length of 600 msec, increased during recainam loading infusion by 44%, from 38.8% +/- 2.8 to 53.0 +/- 5.4 msec; intranodal conduction time increased by 10%, from 102.0 +/- 5.5 to 112.1 +/- 5.2 msec; and infranodal conduction time increased by 31% from 53.1 +/- 3.0 to 70.7 +/- 3.8 msec. Slowed conduction persisted during washout. The mean right atrial effective refractory period was significantly prolonged (+7% at 600 msec cycle length and +8% at 450 msec cycle length, P less than 0.05 and P less than 0.01, respectively) during recainam loading and remained so during washout.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1990

PR interval behavior during exercise: implications for physiological pacemakers.

The relationship between heart rate response and the dynamic changes in the PR interval was assessed in 631 patients undergoing routine cardiac exercise tests for a variety of clinical indications. Patients were stratified into four subsets: nonmedicated normals (n = 437), patients on beta-antagonist agents (n = 118), those on antiarrhythmic agents alone (n = 61) and those with a clinical diagnosis of advanced (New York Heart Association [NYHA] Class III or IV) congestive heart failure. All patients were in stable sinus rhythm throughout the test. PR intervals were measured at rest, at mid-exercise and at peak exercise. Mean PR intervals shortened to a statistically significant degree in most subgroups. This effect was predominantly observed in the earlier stages of exercise. In patients with advanced heart failure, there was no statistically significant shortening of exercise PR intervals later in exercise, demonstrating a parallel with their relatively blunted heart rate response. These changes in exercise PR intervals suggest that implanted pacemaker algorithms may be constructed to maximize hemodynamic benefit in patients requiring physiological pacemakers.

Adolescent↗

PubMed1989

Effects of supernormal capture on directly measured nonmodulated parasystolic cycles.

Pacemaker capture during the supernormal period was seen in a case of modulated parasystole where ectopic cycles occurred without any interposed nonparasystolic beat. This contrasts with previous clinical reports, since, in the latter, the parasystolic cycle length could not be measured directly. As in experimental studies, supernormal modulation resulted in a triphasic phase response curve. Although less likely, similar electrocardiographic changes could be produced by a conceptually different phenomenon, namely full parasystolic resetting due to loss of protection occurring exclusively early in the cycle, combined with modulation in the other (late) parts of the cycle.

Aged↗

PubMed1989

Time to first shock and clinical outcome in patients receiving an automatic implantable cardioverter-defibrillator.

The relation between time to first shock and clinical outcome was studied in 60 patients who received an automatic implantable cardioverter-defibrillator (AICD) from August 1983 through May 1988. The mean (+/- SD) patient age was 64 +/- 10 years, 82% were men and the mean ejection fraction was 33 +/- 13%. During follow-up, 38 patients (63%) had one or more shocks; there were no differences in age, gender distribution or ejection fraction at entry between the shock and no shock groups. Among 51 patients with coronary artery disease, 31 (61%) had one or more shocks, whereas all seven patients with cardiomyopathy had one or more shocks (p less than 0.05). Neither of the two patients with idiopathic ventricular fibrillation had shocks. Of the 13 deaths, 12 occurred during post-hospital follow-up and 1 during the index hospitalization. Of the four sudden post-hospital deaths, only one was due to tachyarrhythmia in the absence of acute myocardial infarction. All four sudden deaths and five of eight post-hospital nonsudden deaths occurred in patients who had had one or more appropriate shocks during follow-up. Eight of the nine first appropriate shocks among patients who subsequently died occurred within the first 3 months of follow-up, but the actual deaths were delayed to a mean of 14.1 +/- 13.9 months (p less than 0.05). The mean time to all deaths was 14.8 +/- 13.1 months. The ejection fraction was significantly lower among patients who died than among patients who survived (25 +/- 7% versus 35 +/- 14%, p less than 0.02), but it did not distinguish risk of first shocks.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗

PubMed1988

Mechanism of death in patients with the automatic implantable cardioverter defibrillator.

Fifty patients underwent primary implantation of an automatic implantable cardioverter defibrillator between August 1983 and April 1988 and were entered into a long-term surveillance program. There were a total of 14 deaths (28%) in the entire group occurring at a mean of 8.7 months postimplantation. Eleven deaths were cardiac and three were noncardiac (two pneumonia, one leukemia). The group of deceased patients were similar to the survivors in all respects except for a statistically lower ejection fraction (23% vs 32%) at the time of implantation. In addition, 13/14 (93%) of the deceased patients experienced at least one appropriate AICD discharge at a mean of 4.5 months post implantation. Recorded ECGs at the time of death revealed that most of the sudden deaths were due to electromechanical dissociation and not to AICD-treatable arrhythmias. These data suggest therefore that death in AICD patients is usually cardiac, due primarily to low ejection fraction and occurs in patients who have previously received AICD discharges.

Adult↗

PubMed1987

Unstable intraventricular conduction disorders.

Unstable bundle branch blocks may be tachycardia dependent, bradycardia dependent, or rate independent. When appearing at the "critical" rates or "critical" cycle lengths they may seem to be rate independent. Conversely, "true" rate-independent blocks may be reversible or irreversible. Determining if a rate-unrelated block may disappear can be difficult because irreversile bundle branch block seems to develop through a slow process in time during which rate-dependent, rate-independent, and even normal conduction alternate in successive electrocardiograms.

Bradycardia↗

PubMed1986

Linking phenomenon during atrial stimulation with accessory pathways.

Linking is an electrophysiologic phenomenon in which each successive impulse entering a macroreentry circuit propagates preferentially along 1 limb because of the functional impedance to conduction in the contralateral limb produced by the previous impulse. Electrophysiologic studies were performed in 12 patients with a bidirectionally conducting accessory pathway. Linking was analyzed while 1:1 atrioventricular conduction took place through the normal pathway. When atrial pacing (at the same cycle length) could be initiated during sinus rhythm in patients with rapidly conducting accessory pathways, linking was dynamically maintained by repetitive local refractoriness (interference). When it could be initiated during the usual type of orthodromic circus movement tachycardia, linking was sustained by actual impulse collision, the underlying mechanism having also been called entrainment. When it could be initiated during sinus rhythm in a patient with a slowly conducting accessory pathway, linking was maintained by impulse collision, but the underlying mechanism could not be called entrainment because stimulation had not been started during tachycardia. This study showed that 2 terms--linking and entrainment--may be applied to the same mechanism and, conversely, that the same name could not be used in reference to the same mechanism when pacing was initiated under different circumstances. However, using the proposed conceptual formulation for linking, it is apparent that seemingly diverse mechanisms associated with macroreentry circuits involving accessory pathways are, in fact, variations on a common electrophysiologic theme.

Adolescent↗

PubMed1986

Automatic implantable cardioverter-defibrillator: techniques of implantation and results.

An initial experience with use of the automatic implantable cardioverter-defibrillator (AICD) is described. Twelve patients received the device. One death has occurred during a mean follow-up of 15 months, and it was due to causes other than arrhythmias. Appropriate device discharge terminating a malignant arrhythmia occurred in 9 patients (75%). The observed survival (92%) far exceeds that to be expected in survivors of sudden death treated by conventional means. There have been no operative deaths. Morbidity has been minimal, although three reoperations were required in 2 patients because of lead dislodgment. The AICD has been demonstrated to be effective in treating patients at risk for sudden arrhythmic death. It can be employed safely with minimum morbidity using a variety of implantation techniques.

Aged↗

PubMed1986

Noninvasive conversion of atrial flutter using a multiprogrammable DDD pulse generator.

A patient with sick sinus syndrome and resistant paroxysmal atrial flutter was treated with amiodarone and implanted with a Medtronic 7005 DDD pacemaker. Following discontinuation of amiodarone, an episode of sustained atrial flutter was converted to sinus rhythm by noninvasive rapid atrial pacing in the outpatient clinic. This case illustrates one of the many capabilities for arrhythmic intervention using currently available implanted pacemakers.

Amiodarone↗

PubMed1986

The automatic implantable cardioverter-defibrillator: results, observations, and comments.

The automatic implantable cardioverter-defibrillator (AICD) is a device of proven efficacy in life-threatening ventricular tachycardia and fibrillation. Initial experience with the AICD at the University of Miami consists of 21 patients with recurrent ventricular dysrhythmias for a total follow-up of 3-35 months (mean 19). There were two deaths in the series, one nonarrhythmic and one arrhythmic, at the fifth and tenth postoperative months respectively. There were five complications requiring reoperation in three patients. Pacemakers were required in four patients with the AICD and resulted in interesting observations. Our data concur with previously published reports of improved survival in selected patients.

Adult↗

PubMed1986

Surgical management of post-myocardial infarction ventricular tachyarrhythmia by myocardial debulking, septal isolation, and myocardial revascularization.

Sustained ventricular tachycardia or ventricular fibrillation, associated with severely depressed left ventricular function after myocardial infarction, carries a poor prognosis. We have used an extensive surgical procedure in 18 patients (15 men and three women) with a mean age of 63 years who had more than three episodes of recurrent, hemodynamically significant ventricular tachycardia or fibrillation and congestive heart failure. The operation consisted of complete myocardial revascularization and myocardial debulking by extensive infarctectomy with unguided endocardial resection and septal isolation with support of the necrotic wall with a Teflon patch. Implantable defibrillator patches were placed in eight patients. Blood cardioplegia and intra-aortic balloon assist (12 patients) were used for perioperative myocardial preservation. Postoperative studies demonstrated a significant increase in ejection fraction (n = 16) and a decline in pulmonary wedge pressure. Hospital mortality was 16% (three patients). Two deaths were due to congestive heart failure and one to arrhythmia. During postoperative electrophysiologic studies, ventricular tachycardia was not inducible in six of eight patients (75%). During a mean follow-up of 24 months, 11 of 15 patients who survived operation are alive and are in New York Heart Association Class I or II. Three of four late deaths were due to congestive heart failure and drug toxicity and one was arrhythmia related. This procedure is effective for preventing recurrent ventricular tachycardia or fibrillation in a majority of patients who cannot have intraoperative mapping.

Aged↗

PubMed1985

Concealment of manifest, and exposure of concealed, ventricular parasystole produced by isoproterenol.

Few studies have dealt with the effects of isoproterenol on ventricular parasystole. Intravenous isoproterenol (2 to 4 micrograms/min) was administered to 11 nonmedicated patients with ventricular parasystole. At the onset of the drip infusion, 8 patients had continuous parasystole, 2 had intermittent parasystole, and 1 patient (in whom intermittent parasystole was documented 2 to 5 days earlier) showed no manifest parasystolic activity. In all patients, whose control parasystolic cycle length varied between 960 and 2,530 ms, isoproterenol caused a decrease of the parasystolic cycle lengths ranging from 12 to 36%. Therefore, isoproterenol produced a consistent increase of the parasystolic rate. In 4 patients, parasystolic activity ceased to be manifest when the concomitantly enhanced (by isoproterenol) sinus cycle lengths became shorter than 430 ms. This phenomenon reflected a tachycardia-dependent parasystolic concealment, presumably as a result of interference in the parasystolic-ventricular junction. In every case, the arrhythmia reappeared at its initial rate upon stopping the drip infusion. In no patient did parasystolic ventricular tachycardia develop. In the patient without manifest parasystolic beats, isoproterenol unmasked the intermittent parasystole that previously had been intrinsically manifest. The latter effect reflected a true exposure, or unmasking of a latent, rate-independent concealed, parasystolic focus.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1985

Indications for and management of cardiac pacemakers.

Cardiac pacemakers are now at the forefront of medical technology. The ability to provide pacing therapy adapted to the individual patient has resulted in significant patient benefit. Although the indications for cardiac pacing have changed little over the past decade, the types of pacemakers available for specific bradyarrhythmias have proliferated in leaps and bounds. This technology is complex and sophisticated and requires in-depth knowledge for appropriate utilization. Artificial replacement of the human conduction system is now a reality. Still other advances remain to be achieved in this area, mainly in sensor technology and pacing therapy for tachyarrhythmias. At the current rate of development, the outlook is indeed promising.

Arrhythmias, Cardiac↗