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Biomedical subjects

P Citron

Publications and source records attributed to P Citron.

15 recordsLinked to original sources
PubMed1980

Physiological cardiac pacing.

With the availability of reliable transvenous atrial leads and advances in electronic and battery technology, pacing for the restoration of the atrioventricular sequence has become practicable. This paper presents (1) a historical review of physiological cardiac pacing, and (2) a functional description of pacemakers currently available or in clinical validation. The indications and limitations of use for each is discussed on the basis of clinical experience in 176 patients. Predictions are made for future application of sophisticated pacemaker systems after the remaining clinical and technological barriers are overcome.

Cardiac Pacing, Artificial↗
PubMed1979

Electrophysiological and haemodynamic basis for application of new pacemaker technology in sick sinus syndrome and atrioventricular block.

A fundamental description of pacemaker systems which are commercially available or in clinical validation is given as a background for their application in a series of 62 consecutive patients presenting over a period of 1 year for permanent cardiac pacing. The patients (23 (37%) sick sinus syndrome, 38 (61%) atrioventricular block, and 1 ventricular tachycardia) were studied electrophysiologically and haemodynamically to allow the appropriate application of a pacemaker system. In sick sinus syndrome, 8 patients had permanent atrial pacing, 14 ventricular pacing, and 1 atrioventricular sequential pacing; in atrioventricular block, 8 patients had atrial synchronous ventricular inhibited pacing and the remaining 30 had ventricular pacing. A high incidence of atrial fibrillation, 9 patients, and abnormal sinus node function, 15 patients, precluded wider use of atrial synchrony. The results show benefit in acute haemodynamic studies of using systems including atrial sensing and/or pacing, and with greater availability of atrioventricular sequential and still more advanced pacemakers with dual sensing as well as dual pacing the majority of patients may be offered this benefit.

Aged↗
PubMed1979

Implantable pacemakers for management of tachyarrhythmias.

Attempts have been made to control tachyarrhythmias with implantable pacemakers since the late 1960's. The basic approaches considered were: a) maintenance of a basic rate following surgical division of the conducting system, b) pacing to prevent onset of tachyarrhythmias, and c) pacing to terminate episodes of tachyarrhythmias. The earliest approaches required conscious patient interaction in effecting therapy. Emergence of newer technologies has allowed development of flexible, automatic pacing systems which overcome some of the limitations of earlier approaches.

Cardiac Pacing, Artificial↗
PubMed1978

Clinical experience with a new transvenous atrial lead.

Although systems using atrial pacemakers offer potential clinical advantages for many patients now receiving ventricular devices, atrial systems have been used in less than 1% of the implantations of permanent pacemakers. The unavailability of clinically successful, easily positioned atrial leads is regarded as the most significant factor in the underutilization of atrial pacing systems. A permanent transvenous atrial lead has been developed and has performed well in 16 months of evaluation in 28 patients. Acute thresholds for voltage at a pulse width of 1 msec ranged from 0.40 v to 2.0 v (average, 1.1 v). Acute peak-to-peak amplitudes of the atrial electrogram were notably high, ranging from 2.5 mv to 7.5 mv (average, 5.1 mv) as measured oscilloscopically. Intermittent failure of sensing occurred in three patients during the period immediately after implantations. Spontaneous dislodgment of the lead from the right atrial appendage occurred in two patients. Atrial sensing and pacing functions remained intact in the first case, and no revision was performed. The lead was repositioned in the second patient and has remained in good position. No complications relating to the lead have been noted in the remaining patients.

Adult↗
PubMed1976

Patient-initiated rapid atrial pacing to manage supraventricular tachycardia.

Patient-controlled rapid atrial pacing was used to manage 12 cases of recurrent supraventricular tachycardia refractory to drug therapy. The pacing system consists of an implanted receiver-lead system and an external patient-activated transmitter. In each case, brief periods (5 to 20 seconds) of rapid atrial pacing were effective in terminating the supraventricular tachycardia and resulted in a return to normal sinus rhythm. In three patients, occasional transient episodes of atrial flutter or atrial fibrillation preceded a spontaneous return to normal sinus rhythm. The pacing system was removed in one patient 13 months postoperatively because of persistent pericarditis; one patient died of an unrelated cerebral hemorrhage 13 months postoperatively. Successful management of supraventricular tachycardia has been maintained in the 10 remaining patients for 15 to 36 months (average 26.4). In more than 6,000 patient applications of rapid atrial pacing, there has been only one failure to convert the tachycardia. Successful application of permanent rapid atrial pacing requires (1) prescreening of patients with temporary external rapid atrial pacing to verify susceptibility to conversion of supraventricular tachycardia and absence of anomalous conduction pathways that may permit conduction of rapid pacing rates to the ventricles, and (2) assessment of the patient's ability to use the transmitter properly.

Adult↗
PubMed1976

Permanent pervenous atrial sensing and pacing with a new J-shaped lead.

We have developed a new J-shaped lead for atrial pacing. The lead has silicone rubber tines which become entangled in the trabeculae and thereby anchor the lead firmly in the left atrial appendage. Later, scar tissue forms around the tines, rather than around the electrode, so that there is no problem with either lead displacement or loss of sensing.

Aged↗
PubMed1975

The triple pulse generator: Clinical evaluation of a new multipurpose external pulse generator.

This report describes our experience with a new, versatile battery operated, multi-purpose pulse generator especially designed for the electrophysiological investigation and treatment of cardiac arrhythmias in man. The unit was constructed according to our specifications and has been clinically in 75 patients over a period of 18 months. We have found the triple pulse pacemaker safe, reliable and functioning precisely according to specifications both clinically and when repeatedly checked with a storage oscilloscope.

Arrhythmias, Cardiac↗