bluuebunny/crossref_metadata_2025 huggingface dataset:
Procainamide in the Induction and Perpetuation of Ventricular Tachycardia in Man
Authors: KANG PRITPAL S. , GOMES JOSEPH ANTHONY C. , EL‐SHERIF NABIL
Published: July 2006

The effects of a single intravenous infusion of 750 mg of procainamide was studied in 12 patients with symptomatic chronic recurrent ventricular tachycardia in whom ar rhythmias could reproducibl be initiated and terminated by programmed electrical stimulation of the heart. Sustained ventricular tachycardia was induced in 6 patients and non‐sustained tachycardia was induced in the remaining 6 patients during control studies. Following procainamide (plasma level 10.3 ± 3.7mcg/ml), ventricular tachycardia couid be induced in 10/12 patients, sustained in 4 patients and non‐sustained in the remaining 6 patients. In 8/12 patients (66%). induction of ventricular tachycardia was facilitated as demonstrated by: (1) tachycardia zone was widened in 4 patients and was un changed in another 3 patients; (2) non‐sustained ventricular tachycardia was changed to sustained ventricular tachycardia in one patient. The ventricular tachycardia had a faster rate and a different QRS morphology; (3) in 4 patients tachycardia was inducible with a lesser number of extrastimuli an d/or hy spontaneously occurring ventricular premature depolarization and; (4) increase of the num ber of induced ventricular responses of non‐sustained ventricular tachycardia. In 4/12 patients (33%), procainamide abolished or modified the induction of ventricular tachycardia as demonstrated by: (1) inability to induce ventricular tachycardia in 2 patients; (2) narrowing of the tachycardia zone and conversion from sustained into non‐sustained ventricular tachycardia (one patient) and; (3) decrease in the number of induced ventricular responses in one patient. The response to procainamide could not be predicted from rates of spontaneous ventricular tachycardia, induced ventricular tachycardia during control studies, degree of slowing of ventricular tachycardia or from prolongation of the coupl ing interval after procainamide. These results suggest that instead of abolishing the arrhythmia, pro cainamide in frequently employed doses in patients with chronic recurrent ventricular tachycardia can facilitate its initiation sometimes at even faster rates. Patients not responsive to the usual doses of procainamide should undergo acute drug testing trials to determine the optimal dose/drug levels. (PACE, Vol. 5, May‐June, 1982)
Transverse Dissociation of the Human His Bundle
Authors: ELENCWAJG BENJAMIN , ZAMAN LIAQAT , ROZANSKI JOHN J. , MYERBURG ROBERT J. , CASTELLANOS AGUSTIN
Published: July 2006

“Completed” and “abor tive” alternating Wenckebach periods occurred in a symptomatic female with calcification of the mi tral annulus, These arrhythmias were attributed to transverse dissociation of the His bundle into two horizontal levels “connected in series,” with 2:1 block in the “distal” level and Wenckebach periods in the “proximal” level. Intra‐Hisian alternating Wenckebach periods resembled those resulting from transverse dissociation of other infra‐AV nodal structures in that they are rare, usually symptomatic and require pacemaker implantation. This contrasts with the variety of rhythms resulting from trans verse dissociation of the AV node which occur frequently, are not always malignant, and generally are not treated with implanted pacemakers. (PACE, Vol. 5, May‐June, 1982)
Evidence of Low‐Grade Intravascular Coagulation in Patients with Transvenous Pacemakers
Authors: CHRISTOPOULOU‐COKKINOU VANA , KOUREPI‐LOGOTHETI  , KONTAXIS ARGYRIS , MALLIOS CONSTANTINE , VORIDES EUTYCHIOS M. , COKKINOS DENNIS V.
Published: July 2006

Serum fibrin and fibrinogen degradation products (FDP) were measured in 4 groups of patients. In Group A (30 patients) FDP levels were measured before and 48–60 hours after pacemaker and transvenous electrode placement. They remained negative (< 10 μg/ml) in 14, rose to > 10μg/ml < 40μyg/ml in 12, and > 40 μg/ml in 4. In 12 Group B patients undergoing the same procedure, FDP levels remained negative in 8, and rose in 4 after 24 hours and after 7 days. In 12 Group C patients sludied at initial electrode and battery implantation and 3‐6 months later, there were the same results in short‐ and long‐term FDP measurements (8 negative and 4 elevated). Finally, in 14 patients with negative FDP levels who underwent battery replacement only. 3.1 to 5.2 years after their in itial operation (Group D, no increase of FDP titer was seen postoperatively. Our results suggest that elevated FDP levels suggest subclinical intravenous or intracardiac thrombosis in patients with trans venous pacemakers. (PACE, Vol. 5, May‐June, 1982)
Alternans of the ST Segment and T Wave. A Sign of Electrical Instability in Prinzmetal's Angina
Authors: ROZANSKI JOHN J. , KLEINFELD MORRIS
Published: July 2006

A sign of electrical instability in Prinzmetal's angina. In an effort to determine the incidence of ventricular arrhythmias associated with ST segment alternans. the potterns of ST segment and T‐wave electrical alternans (STEA) were analyzed in 93 patients during spontaneous Prinzmetal's angina. Twenty‐eight of 93 patients, or 30% (Group I), showed STEA during episodes of ST segment elevation. Sixty‐five of 93 patients, or 70% (Group II), showed no alternans during episodes of ST segment elevation. In Group I, ventricular arrhythmias, defined as all ventricular ectopic activity greater than 5 beats per minute and complex Lown grades III to V, occurred during 52 of 55 episodes, or 95%; whereas in Group II, ventricular arrhythmias occurred in only 51 of 125 episodes, or 41% (p < 0.01). The difference in the incidence of ventricular fibrillation (VF) or ventricular tachycardia (VT) in the two groups was more striking, VT or VF occurred in 20 of 55 in Group I (36%) versus 5 of 125 in Group II (47%). Although there were no significant differences in age or sex between Group I and II patients, there was a significant difference in the magnitude of the maximum ST segment elevation (5 mm in Group I versus 3 mm in Group II, p < 0.01). This study demonstrates that the occurrence of STEA and T wave alternans frequently heralds the onset of ventricular arrhythmias in Prinzmetal's angina. Both the arrhythmias and the alternans occur during the time of maximal ST segment elevation. (PAGE, Vol. 5, May‐June, 1982)
The Automatic Implantable Defibrillator
Authors: MIROWSKI M. , MOWER MORTON M. , REID PHILIP R. , WATKINS LEVI , LANGER ALOIS
Published: July 2006

New Modality for treatment of life‐threatening ventricular arrhythmias. The automatic implantable defibrillator continuously monitors cardiac rhythm, identifies ventricuiar fibrillation and then delivers corrective defibrillatory discharges when indicated: it weighs 250 grams and has a volume of 145 cc. When a suitable arrhythmia is detected, a 25 Joule pulse is delivered through a superior vena cava catheter electrode and another electrode placed over the cardiac apex. As oj March 1981, sixteen survivors of multiple cardiac arrests refractory io antiarrhythmic therapy had undergone implantation of the automatic defibrillator. There was no operative mortality and the morbidity was minimal. Electrophysiologic studies were performed before and after surgery to confirm failure of drug therapy and to ensure the device's ability to terminate malignant arrhythmias. Eight spontaneous and fourteen of the seventeen induced malignant arrhythmias were properly recognized and corrected by the device. The discharges were well tolerated by awake patients. A number of problems including recycling delays and spurious discharges have been identified and corrected. There were three late deaths with pulmonary edema noted in two patients, and asystole in one. The autopsies revealed no myocardial damage attributable to the automatic defibrillator. Although the ultimate role of this approach to prevention of sudden arrhythmic death has yet to be determined, the results obtained to date are encouraging and indicate that a useful modality for treating malignant ventricular arrhythmias has been added to our armamentarium. (PACE, Vol. 5, May‐June, 1982)
Pacemaker Related Tachycardias
Authors: DEN DULK KAREL , LINDEMANS FRED W. , BÅR FRITS W. , WELLENS HEIN J.J.
Published: July 2006

Three cases of pacemaker interactive tachycardia are presented. The first two are (artificial) circus movement tachycardias. In the first one the retrograde arm of the tachycardia circuit was provided by the A‐V node and the antegrade arm by an atrial synchronous pulse generator. In the second case, the A‐V node and, coincidentally, an A‐V sequential pulse generator alternately provided the antegrade arm while the retrograde arm was by way of an accessory pathway. In the third case ventricular inhibition during A‐V sequential pacing gave the paced atrial events the chance to be conducted to the ventricles with a long A‐V interval. This resulted in a tachycardia with a rate of 150 bpm, instead of the programmed rate of 110 bpm. (PACE, Vol. 5, July‐August, 1982)
Endless Loop Tachycardia in an AV Universal (DDD) Pacemaker
Authors: FURMAN SEYMOUR , FISHER JOHN D.
Published: July 2006

Implantation of an A V universal (DDD) pacemaker, stimulating and sensing both atrium and ventricle caused a pacemaker mediated tachycardia, begun by a P wave occurring after a premature ventricular contraction, and sustained by P waves caused by retrograde AV conduction. The tachycardia was terminated by application of a magnet to the pulse generator which temporarily made it insensitive to incoming signals, both P and QRS. (PACE, Vol. 5. July‐August, 1982)
Recurrent Ventricular Tachycardia Induced by an Atrial Synchronous Ventricular‐Inhibited Pacemaker
Authors: FREEDMAN ROGER A. , ROTHMAN MARTIN T. , MASON JAY W.
Published: July 2006

Atrial synchronous pacemakers have been known to cause a variety of cardiac arrhythmias. Of particular concern are those arrhythmias invoiv ing a pacemaker stimuius occurring on a T wave, because these may lead to ventricuiar tachycardia. The Medtronic 2409 ASVIP pacemaker is an atrial synchronous pacemaker with several features de signed to decrease the likelihood of such arrhythmias. We report a patient in whom a normally func tioning Medtronic 2409 ASVIP pacemaker, despite these features, induced recurrent ventricular tachycardia. Conditions which predisposed this patient to pacemaker‐induced re‐entrant arrhythmias are discussed. [PACE, Vol. 5, July‐August, 1982]
Clinical Use of a New Myocardial Electrode
Authors: JAUSSERAN JEAN‐MICHEL , TIMPONE GÈRARD , FORMICHI MAXIME , PISAPIA ANDRÈ
Published: July 2006

Prior to clinical use, this new myocardial stimulating electrode was studied in animals in order to test its electrical and mechanical reliability. The Telectronics 030.168 electrode consists of a conductor constructed of 3 stainless steel wires. Its present surface area is 25 mm2 and its length is 10 mm. The device is easily inserted into the myocardium with a suture and needle and is held in place with a surgical clip. We report observations on 42 patients made over an average follow‐up period of 14.6 months. There were no surgical complicotions and there was no operative mortality. Calculated as an average of recorded electrical measurements, the stimulating threshold was 1.03 volts and 2.40 mA at 500 ms. None of the patients have required further surgery and no malfunctions have been discovered, (PACE, Vol. 5, July‐August, 1982)
Projecting Demand for Cardiac Pacemakers
Authors: RONEN BOAZ , PLISKIN JOSEPH S. , FELDMAN SCHLOMO
Published: July 2006

A cardiac pacemaker implantation program involves substantial resources of money, facilities, and manpower. This paper presents a model for forecasting future numbers of implants, thus enabling the more effi‐cient use of such resources. The model embraces both new implants and replacements, both shortterm and long‐term planning, and can be used with relevant data from any source. (PACE, Vol. 5, July‐August, 1982)
Noninvasive Recording of His‐Purkinje System (HPS) Activity in Man on Beat‐To‐Beat Basis
Authors: KĘPSKI ROMAN , PLUCIŃSKI ZBIGNIEW , WALCZAK FRANCISZEK
Published: July 2006

Since 1969 His bundie electrography has been used for diagnosis and for the study of cardiac electrophysiology. This method has employed the catheterization technique and has allowed the continuous recording of electrical activity of the specialized cardiac conduction system in every beat. Such investigation, because of its invasive nature, cannot be considered a routine test; it requires expensive instrumentation, it has physiological and technical limitations that include discomfort, a slight morbidity risk and a rather limited recorded area within the heart. In 1973 a method was developed for a noninvasive recording of the electrical activity within the P‐R segment of the electrocardiogram measured from the body surface. This method which employs the signal averaging technique delivers even less medical information than intracardiac measurement. The shortcomings of this averaging method include inability to detect beat‐to‐beat changes in the true signal. Such a method is not useful in transient arrhythmia detection and a “short acting” drug influence examination. The technical approach to the beat‐to‐beat noninvasive recording of the HPS activation signal as measured from the body surface has been proposed. Using a specially positioned electrode system, a low noise multiple parallel input amplifier and a computer for sampling, processing and plotting of the measured signal, wehave obtained an output curve corresponding to the continuous beat‐to‐beat HPS activity. (PACE, Vol. 5, July‐August, 1982)
Effect of Isoetharine on Cardiac Conduction in Man
Authors: GOULD LAWRENCE , REDDY C.V.R. , PATEL S. , GOMES G. , MACKLIN E.
Published: July 2006

The effects of isoetharine on the His bundle electrogram were studied in 10 patients with heart disease. Recordings were made at varied heart rates using atrial pacing, Isoetharine significantly reduced the AH interval with atrial pacing, but it had no effect on the HV interval. Second degree heart block occurred at higher pacing rates after isoetharine treatment as compared to the control state. The heart rate and blood pressure showed no significant change after isoetharine. The functional and effective refractory periods were measured with the use of the extra‐stimulus technique. The functional refractory period of the AV node, as well as the effective refractory period of the atrium, significantly decreased after isoetharine. Thus, isoetharine can improve conduction through the atrioventricular node. The drug does have a cardiac effect as measured by its action on the human conduction system. (PACE, Vol. 5, July‐August, 1982)
Bradycardia‐Tachycardia Syndrome Due to Sinus Node Disease and Concealed Wolff‐Parkinson‐White Syndrome
Authors: CIVERA ROBERTO GARCIA , BONNIN JOAQUIN SEGUI , MAŃEZ RAFAEL SANJUAN , CABEDO SALVADOR MORELL , SANCHIS JUAN LLAVADOR
Published: July 2006

A 75‐year‐old woman was admitted to the hospital because of a supraventricular tachycardia, long sinus pauses and ventricular tachycardia of the torsades de pointe type. Temporary ventricular pacing suppressed ventricular arrhythmias but supraventricular tachy‐cardia persisted. An electrophysiologic study revealed the coexistence of sick sinus syndrome and cir‐cus movement tachycardia due to a concealed left‐sided accessory atrioventricular pathway. This case represents a previously undescribed form of the bradycardia‐tachycardia syndrome. (PACE, Vol. 5, July‐August, 1982)
Induced Concealed Dissimilar Atrial Rhythms
Authors: RAKOVEC PETER , HORVAT MATIJA , JAKOPIN JAPEC , KENDA MIRAN F. , KRANJEC IGOR , JAGODIC ANTON
Published: July 2006

Electrophysiologic studies, including intra‐atrial recordings and atrial stimulation, were performed in two patients with suspected sick sinus syndrome. Premature atrial stimuli induced atrial flutter in both patients. The arrhythmia was concealed, i.e., it was recordable only by intracavitary electrogram and invisible on surface electrocardiogram. In one case, simultaneous atrial fibrillation could be recorded in a segment of the right atrium. In this patient, the rhythm on the surface electrocardiogram changed during the study to “upper nodai” rhythm, though the atrial electrogram showed continuation of A waves at the same rate as before during sinus rhythm. It seems that atrial changes, which are frequently encountered in sick sinus syndrome, are a predisposing factor for spontaneous or inducible concealed atrial arrhythmias. (PACE, Vol. 5, July‐August, 1982)
The High Impedance Dish Electrode—Clinical Experience with a New Tined Lead
Authors: MOND HARRY , HOLLEY LORAINE , HIRSHORN MICHAEL
Published: July 2006

To reduce current drain and thus optimize pulse generator longevity, 25 unipolar trailing tined leads with a 6 mm2 platinum electrode shaped as a dish were implanted in suitable patients and compared to a patient series in which 25 standard unipolar trailing tined leads with an 8 mm2 standard platinum electrode were implanted. Comparing the two patient groups there were no significant differences in age, sex, diagnosis or vein used. Comparing implant data: mean voltage threshold was 0.50 ± 0.13 V (standard deviation) for the group with the dish electrode and 0.60 + 0.14 V for the group with the standard electrode (p < 0.02). The mean current threshold was 0.64 ± 0.18 mA for the dish electrode and 0.88 ± 0.25 mA for the standard electrode (p < 0.001). The mean calculated impedance was 758± 149 ohm for the dish electrode and 598 ± 104 ohm for the standard electrode (P < 0.001). R wave amplitude was a mean of 7.4 ± 4.3 mV (dish electrode) and 7.4 ±3.7mV (standard electrode). There were two deaths; one at twelve months, cause unknown, and the other from a postoperative hemopericardium due to right ventricular perforation from the temporary pacing lead. The only complication was an electrode retraction from the endocardium. In seven patients with dish electrodes, pulse generators able to measure voltage threshold (Vario) non‐invasively were used. Mean postoperative voltage thresholds were as follows: 24 hours 0.64 V, 48 hours 0.68 V, two weeks 1.44 V, three months 1.30 V and six months 1.40 V. Thus, at implant the lead with the dish electrode had a significantly higher impedance (21%), lower voltage threshold (17%) and lower current threshold (27%) compared to a standard lead. R wave amplitude was normal. Follow‐up voltage threshold Jevels to data suggest that lale high thresholds are unlikely. Thus, the tined lead with the high impedance dish electrode is likely both to reduce lead complications and to improve pulse generator longevity. (PACE, VoJ. 5, July‐August. 1982)
Electronic Pacemaker Models of Parasystole
Authors: CASTELLANOS AGUSTIN , CASTILLO CESAR A. , MEDINA‐RAVELL VICTOR , MOLEIRO FEDERICO , BERKOVITS BAROUH V. , MYERBURG ROBERT J.
Published: July 2006

With special reference to artificial intermittent parasystole with phase 3 and phase 4 protection and to parasystolic modulation. This study deals with a method of analysis of artificial pacemaker function which can he used to understand the electrocardiographic manifestations of some spontaneous rhythms. The modes of operation of 11 normaily‐functioning QRS‐inhibited (VVI) pacemakers resembled those of spontaneous automatic nonprotected (nonparasystolic) rhythms. The function of 11 continuous asynchronous (fixed rate or VOO) pacemakers was similar to that of continuous‐parasystolic rhythms. In 12 patients with malfunctioning QRS‐inhibited (VVI) pacemakers, an abnormally‐prolonged pacemaker refractory period was equivalent to intermittent parasystole with phase 3 protection; and non‐sensing during the terminal portions of the cycle was the iatrogenic counterpart of intermittent parasystole with phase 4 protection. Premature beats occurring within the periods of phase 3 and phase 4 protection were “encompassed” by ectopic intervals equalling the ectopic cycle length, or twice the ectopic cycle length. Therefore, they were manifested differently from the “decelerating” and “accelerating” phases of modulation since premature beats occurring during the letter phases may be encompassed by ectopic intervals which are longer and shorter, respectively, than the ectopic cycle length. Because in previous reports the search for these phenomena was based on premises established “a priori,” future studies should be designed to analyze tracings of “group beating” where no previous conclusions have been reached. (PACE, Vol. 5. July‐August, 1982)
Electrophysiology and Indications for Pacing in the ‘8O’s*
Authors: LÜDERITZ BERNDT
Published: July 2006

Bradycardias originate either from a dysfunction of impulse formation in the sinoatrial node or from a disturbed conduction of the impulse. Different pathogenetic mechanisms are discussed as causes of tachyarrhythmias; circus movement (re‐entry) is primarily due to pathological changes in conduction and refractoriness. Focal impulse formation results from local disturbances of depolarization and repolar‐ization of the cell membrane: increased automaticity, abnormai outomaticity, triggered activity. Symptomatic bradycardias still represent the standard indication for cardiac pacing particularly with implantable pacemakers. Based on clinical electrophysiology, various types of pacemakers are available at present: atrial triggered and atrial pacing pacemakers, AV‐sequential pacemakers, ventricuiar demand‐pacemakers, stand‐by pacemakers, and fixed rate pacemakers. The multiprogrammability of newer pacemaker devices is a very useful tool in avoiding secondary interventions. For antitachycardia pacemaker therapy there are essentially three methods in use: 1. overdrive pacing to prevent re‐entry phenomena and automaticity and also to suppress tachyarrhythmias based on increased or abnormai automaticity; 2. competitive stimulation for termination of tachycardias by means of single impulses; and 3. rapid atrial stimulation to convert atrial flutter into atrial fibrillation and consequently to normal sinus rhythm. In very rare cases rapid ventricular stimulation is mandatory. The positive results achieved with temporary stimulation methods have led to the development of permanent (impiantable) antitachycardia pacemakers for long‐term therapy, which have proven to be a low‐risk alternative in drug‐resistant tachyarrhythmias. (PACE, Vol. 5, July‐August, 1982)
Syncope Caused by Cough‐Induced Complete Atrioventricular Block
Authors: HART G. , OLDERSHAW P.J. , CULL R.E. , HUMPHREY P. , WARD D.
Published: July 2006

Cough syncope is a well‐recognized syndrome in which loss of consciousness follows a bout of prolonged coughing. The pathophysioiogy of this syndrome has been attributed to lowered cerebral perfusion pressure consequent on an increased intrathoracic pressure, which lowvers cardiac output (by a Valsalva mechonism) and impairs cerebral venous return. We report a case of cough‐induced syncope in which ECG monitoring showed that coughing produced paroxysmal atrioventricular block with ventricular asys tole. Such a case has not previously been documented. (PACE, Vol. 5, July‐August, 1982)
Elimination of Lead Dislodgement by the Use of Tined Transvenous Electrodes
Authors: SNOW NORMAN
Published: July 2006

Pacemaker lead dislodgement has accounted for a large proportion of the postoperative complications seen after transvenous pacemaker insertion. Ninety‐two patients underwent implantation of a tined transvenous electrode over a three‐year period without a single dislodgement. Excellent thresholds were obtained and no difficulties related to electrode insertion were encountered. Tined transvenous pacemaker leads are preferred for routine use at this time. (PACE, Vol. 5, July‐August, 1982)
The Electropharmacology of Acute Drug Testing Using Pacemakers
Authors: ENGEL TOBY R.
Published: July 2006

Acute drug testing in patients is useful to select prophylactic treatment for life‐threatening or intractable tachycardias. This is generalJy done by induction of tachycardias with pacing. Acute studies that depend on temporary insertion of pacing electrodes do not determine efficacy in the same sense as longer term clinical drug trials because of the biased population referred for testing with pacemakers. However, the pharmaco‐logic activity of compounds can be tested in terms of electrical functions such as conductivity and refractoriness not merely of the heart in general, but also of the arrhythmogenic focus. Such data can be directly applied to patients with similar arrhythmias, obviating the confusion often caused by interspecies and disease differences. (PACE, Vol. 5, July‐August 1982)
A Specific ECG Triad Associated with Congestive Heart Failure
Authors: Barold S. Serge , GOLDBERGER ARY L.
Published: July 2006

No specific ECG sign of congestive heart failure has been described. This report deiineales a new triad consisting of 1) High precordial QRS voltage (SV1 or SV2 + RV5 or RV6 ≥ 3.5 mV); 2) Relatively low limb lead voltage (total QRS amplitude ≤ 0.8 m V in the limb leads); 3) Poor precordial R wave progression (R/S ratio < 3 in V4). In a retrospective study of 27 patients with idiopathic congestive cardiomyopathy, this triad was noted on at least one occasion in 19 cases (70%). This pattern was not noted at all in a control group of 100 adults without heart disease or in a separate control group of 30 preoperative patients with left venlricular hypertrophy due to aortic valve disease and normal left ventricular function. Three of these patients subsequently developed this pattern as a false positive sign immediately following aortic valve replacement. In a prospective survey of ECGs from 2000 consecutive patients, this triad appeared in 32 cases (1.6% prevalence). Definite evidence of current or previous left ventricular failure, usually severe, was noted in 29 of these cases (91% predictive valuel as evidenced by pulmonary venous hypertension or pulmonary edema on chest x‐ray, left ventricular ejection fraction ≤ 40%, or echocardiographic left ventricular end‐diastolic dimension ≥ 6.0 cm. The pathophysiology of this highly specific ECG triad probably relates to a number of mechanical and vectorial factors associated with congestive heart failure of a variety of etiologies. Left ventricular enlargement causes increased precordial voltage. In addition, the horizontal plane vector shifts posteriorly, orthogonal to the frontal plane, causing poor R wave progression and low limb lead voltage. Finally, increased extracellular fluid may preferentially attenuate QRS voltage in the more distal (limb) leads. (PAGE, Vol. 5, July‐August, 1982)
Clinical and Electrophysiological Properties of a New Temporary Pacemaker Lead after Open‐Heart Surgery
Authors: BREIVIK KJELL , ENGEDAL HOGNE , RESGH FIN , SEGADAL LEIDULF , OHM OLEJØRGEN
Published: July 2006

A new temporary pacemaker lead, Medtronic 6400, with a solid defined electrode surface area of 7.5 mm2, has been impianted in 50 patients after open‐heart surgery. One electrode was inserted intramyocardially on the right ventricle, while another was placed extracardially and served as a reference lead. Forty‐six of the patients were followed postoperatively with measurements of myocardial stimulation threshold and resistance. In 25 of the patients, electrograms were recorded on magnetic tape for further computer analysis of amplitudes, slew rates, and signal source impedance. During constant current pacing, myocardial stimulation threshold increased from a median of 0.4 mA one hour postoperatively to a maximum value of 2.3 mA. In two patients (4.3%) intermittent pacing failure was seen. Stimulation resistance fell from a median of 875 Ω, to a minimum of 487Ω, with a subsequent increase to 598Ω before electrode removal. Both mean electrogram amplitude (7.35 mV) and slew rate (0.82 V/s) had their minimum values on the sixth postoperative day. Intermittent sensing failure was observed in 2/25 patients (8%). Signal source impedance was of a magnitude not likely to contribute to sensing failure. No complications were seen from the use of this lead. The new electrode is an important improvement in temporary pacemaker lead design. (PACE, Vol. 5, July‐August, 1982)
Doppler Echocardiography and Cardiac Pacing
Authors: SCHUSTER ALLAN H. , NANDA NAVIN C.
Published: July 2006

There is a need for a non‐invasive method to evaluate the hemodynamic consequences of pacing. The value of Dop pler echocardiography in assessing relative changes in stroke volume and cardiac output is reviewed. We present preliminary observations illustrating the potential value of Doppler echocardiography in cardiac pacing. (PACE, Vol. 5, July‐August, 1982)
Bidirectional Tachycardia. Mechanism Derived from Intracardiac Recordings and Programmed Electrical Stimulation
Authors: LEVY SAMUEL , HILAIRE JEAN , CLEMENTY JACQUES , BARTOLIN ROBERT , BESSE PIERRE , GERARD RAYMOND , BRICAUD HENRI
Published: July 2006

His bundle recordings and programmed electrical stimulation were performed in a 70‐year‐old woman with bidirectional tachycardia; the recordings demonstrated the infra‐Hissian origin of the tachycardia. Occurrence of the His deflection slightly after the onset of ventricular depolarization suggested that the origin of the tachycardia was located near the His bundle bifurcation. Recording of three atrial sites during tachycardia allowed the study of retrograde atrial activation. Two sets of fairly constant and alternating VA intervals were recorded. This fact is consistent with two ventricular circuits used alternatively. The tachycardia could also be interrupted with a single atrial or ventricular premature beat It is postulated that the tachycardia is due to macroreentry involving the two fascicles of the left branch. This study suggests that reentry may be a possible mechanism in some cases of bidirectional tachycardia. (PACE, Vol. 5, September‐October, 1982)
Intrahisian Functional Bundle Branch Block
Authors: IESAKA YOSHITO , ROZANSKI JOHN J. , PINAKATT TERESA , GOSSELIN ARTHUR J. , LISTER JOHN W.
Published: July 2006

The site of block was localized to the area of the His bundle. This case demonstrates that functional complete left bundle branch block may be due to longitudinal dissociution in the His bundle. (PACE, Vol. 5, September‐October, 1982)
Successful Management of Pacing System Malfunctions without Surgery: The Role of Programmable Pulse Generators
Authors: BILLHARDT ROGER A. , ROSENBUSH STUART W. , HAUSER ROBERT G.
Published: July 2006

The value of programmable pulse generators for correcting pacing system malfunction without surgical revision was assessed in 293 patients. Twenty‐five patients (8.5%) developed malfunctions from one day to 38 months after implant. Of these, 16 or 64% were successfully managed by programming alone, while nine patients required lead repositioning or a new lead. The majority (75%) of isolated pacing and sensing maifunctjons were corrected by programming, but programming restored normal pacing function in only one of five patients who had combined sensing and pacing malfunctions which appeared early after pacemaker insertion. We conclude that programmable pulse generators are particularly useful for managing isolated pacing or sensing malfunctions, However, programmabiloity is not a substitute for coreful lead placement. (PACE, Vol. 5. September‐October, 1982]
Electrophysiological Effects of Intravenous Disopyramide Phosphate on the Wolff‐Parkinson‐White Syndrome
Authors: TAJIMA TSUNEMI , DOHI YUTAKA
Published: July 2006

The effects of a single intravenous infusion of 2mg/kg body weight disopyramide phosphate (DP) on the mode of initialion of reentrant supraventricular tachycardia were assessed in seven patients with Wolff‐Parkinson‐White fWPW) syndrome using bundle of His electrograms and the ventricular extrastimulus method. The delta wave disappeared in three potients after DP. However, retrograde conduction via the accessory pathway persisted even ofter DP administration in all patients. These effects contributed to the induction of reciprocating tachycardia after DP. The retrograde functional refractory period of the His‐Purkinje system (HPS) and the effective refractory period of the accessory pathway were increased in all cases and contributed to the development of reentry HPS. After DP. the zone of reentry HPS widened in four cases (including a newly developed case) and remained unchanged in three cases. Reentrant supraventricular tachycardia zones widened in three cases: these widened reentrant supraventricular tachycardia zones were induced by the widened reentry HPS, that is, reentry HPS was followed by the reentrant supraventricu‐lar tachycardia. This study demonstrates that persistence of retrograde accessory pathway conduction and widened reentry HPS which might be dose‐related after DP could be the retrograde determinants affecting the reentrant supraventricular tachycardia zone. (PACE, Vol. 5, September‐October, 1982)
Pacemaker Spike Alternans: An Artifact of Digital Signal Processing
Authors: ENGLER ROBERT L. , GOLDBERGER ARY L. , BHARGAVA VALMIK , KAPELUSZNIK DAVID
Published: July 2006

Marked variability in the amplitude or polarity of pacemaker artifacts may be a clue to generator malfunction or partial electrode fracture. We report a case where “pacemaker spike alternans” occurred factitiously as a result of a digital “roll‐over” effect. The widespread introducfion of digital electrocardiographs into clinical practice makes recognition of such artifacts important, (PACK, Vol. 5, September‐October, 1982)
His Bundle Recordings in Double Tachycardias Not Due to Digitalis Intoxication
Authors: MEDINA‐RAVELL VICTOR , ROZANSKI JOHN J. , CASTELLANOS AGUSTIN
Published: July 2006

Electrophysiological studies were performed in a patient with chronic chagasic cardiomyapathy, recurrent sustained ventricular tachycardia, and a history (without electrocordiographic documentation) of paroxysmal atrial flutter. Ventriculoauricular conduction occurred during short bursts of ventricular pacing. Moreover, the retrograde P of ectopic ven‐tricular heats which appeared after pacing was stopped precipitated an atrial tachyarrhythmia with an irregular atrial rate. In addition, burst ventricular pacing, performed while this atrial tachyar‐rhythmia was present, initiated and subsequently terminated a ventricular tachycardia with similar characteristics to the one occurring spontaneously. The double (alrial and ventricular) tachycardias described in this communication were different from those previously reported in that the arrhythmias were not due to digitalis toxicity, but resulted from the modality of ventricular stimulation performed in a patient who had the specific type of cardiomyopathy seen in the chronic stage of Chagas' disease, (PACE, Vol. 5, September‐October, 1982)
New Permanent Endocardial Atrial J Lead: Implantation Techniques and Clinical Performance
Authors: MESSENGER JOHN C. , CASTELLANET MARK J. , STEPHENSON NANCY L.
Published: July 2006

The potential benefits of pacing systems which restore A‐V synchrony have long been recognized. However, availability of atrial leads which are easily implanted and which consistently perform well has been limited. A new version of the silicone rubber lined J leads is now availabie. Changes were made in the insulation material, conductor configuration, tine configuration, and a J memory coil was added. After over three years of use in 100 patients, we conclude that these leads are easier to implant than previous atrial leads, and that they demonstrate excellent clinical performance. (PACE, Vol. 5, September‐October, 1982)
Mitral Valve Prolapse and Pre‐Excitation
Authors: CHEN WALTER W.C. , WONG PHILIP H.C. , CHOW JOSEPH S.F.
Published: July 2006

Two out of 118 patients with mitral valve prolapse were found to have pre‐excitaiton. The presence of mitral valve prolapse in one patient with Lown‐Ganong‐Levine syndrome and the persistence of prolapse in (he presence and absence of pre‐excitation in another patient with intermittent type B Wolff‐Parkinson‐White syndrome suggest that mitral valve prolapse in pre‐excitation syndrome may not be secondary to the abnormal activation pattern of the left ventricle, which has been suggested as a possible mechanism by some investigators. (PACE, Vol. 5, September‐October, 1982)
Carotid Sinus Hypersensitivity: Diagnosis of Vasodepressor Type in the Presence of Cardioinhibitory Type
Authors: STRYJER DOV , FRIEDENSOHN AHARON , SCHLESINGER ZVI
Published: July 2006

The diagnosis of carotid sinus syncope may sometimes be difficult because its symptoms are not specific, especially in the older age group where carotid sinus hypersensitivity and syncope are not uncommon events. Of major diagnostic importance is the screening of the vasodepressor type of carotid sinus syncope in the presence of the cardioinhihitory type, as this diagnosis has important therapeutic applications. This work is based on the electrophysiological studies performed on seven men with a mean age of 61.9 years who had syncope of unknown cause and hypersensitive carotid sinus reflex. The studies revealed no evidence of sinus node dysfunction or high degree atrioventricular block that would explain the neurological symptoms. The studies also included carotid sinus stimulation with simultaneous interarterial pressure recordings with and without atrial or A‐V sequential pacing. The pacing assured the maintenance of normal heart rate during carotid sinus stimulation. The results of these studies revealed that five patients suffered from cardioinhibitory type and two from a combined form of cardioinhibitory and vasodepressor type (mixed form) of carotid sinus syncope. A permanent cardiac pacemaker was implanted in the five patients with the isolated cardioinhibitory type and in one patient with the mixed type of carotid sinus syncope.
Transvenous Pacemaker Implantation Via a Unilateral Left Superior Vena Cava
Authors: RØNNEVIK PER K. , ABRAHAMSEN ARNE M. , TOLLEFSEN ISAK
Published: July 2006

A 72‐year‐old man with a unilateral left superior vena cava and anomalous drainage of the inferior vena cava required permanent pacing. The anomalies were verified by venography and cardiac catheterization. Difficulties in implantation of a temporary and permanent pacemaker are described. A transvenous endocardial lead was placed in a stable position in the right ventricle. The pacemaker system has now functioned normally for 32 months.
Treatment of Drug Resistant A‐V Reciprocating Tachycardias with Multiprogrammable Dual Demand A‐V Sequential (DVI,MN) Pacemakers
Authors: PORTILLO BOLIVAR , MEDINA‐RAVELL VICTOR , PORTILLO‐LEON NELLY , MADURO CASTOR , MEJIAS JOSE , BERKOVITS BAROUH V. , CASTELLANOS AGUSTIN
Published: July 2006

Programmable dual A‐V sequential demand (DVI,MN) pacemakers were implanted in eight patients with recurrent or incessant, drug‐refractory, A‐V reciprocating tachycardias. This was done after intracardiac studies had identified a variety of electrogenetic mechanisms which include tachycardias involving Kent bundles, (manifest or concealed Wolff‐Parkinson‐White syndrome), nodoventricular (Mahaim) fibers, enhanced A‐V node pathways (Lown‐Ganong‐Levine syndrome), and dual intranodal pathways. The antitachycardia features of the pacemaker were evaluated during the electrophysiological studies. No immediate postoperative complications occurred after implantation. Furthermore, during the follow‐up periods (4 to 20 months), clinical assessment, ambulatory (Holter) monitoring and invasive (as well as noninvasive) evaluations have confirmed continuous effectiveness in recognizing and automatically terminating the tachycardias. Late pacemaker system malfunction has not occurred. The frequency of the tachycardias and the dosage of concomitantly‐administered antiarrhythmic medications were significantly reduced. Furthermore, preliminary studies performed in our laboratory suggest that DVI,MN pacemakers may also be useful in certain types of intra‐atrial reentry tachycardias coexisting with sinus node dysfunction.
Anatomic Substrate for Congenital Atrioventricular Block in Middle‐Aged Adults
Authors: BHARATI SAROJA , ROSEN KENNETH M. , STRASBERG BORIS , RIGBY ELMER , LEV MAURICE
Published: July 2006

Congenital atrioventricular block is usually a benign disorder not necessitating pacing. In some patients slowing of rale and/or mortality have been noted with aging. However an anatomic substrate has not been established for the progressive slowing of the escape rate. In this study we report an anatomic substrate in two such patients who were dying in congestive heart failure, ages 49 and 42, respectively. Multiple pre‐mortem ECG's in both cases revealed wide QRS escape rhythms, and escape rales of approximately 35 and 28 beats/minute, respectively. Conduction system examination by serial section in both cases revealed lack of connection between the atrial septum with the peripheral conduction system with total replacement by fat of the AV nodal approaches and AV node, and advanced sclerosis of the summit of the ventricular septum which was more marked on the right side. In addition, the His bundle showed marked septation in case one and fragmentation in case two. Sclerosis of the summit of the ventricular septum involved the branching bundle and the bundle branches in both cases. In conclusion, both patients had the characteristic lesions of congenital atrioventricular block, namely replacement of the AV node and AV nodal approaches by fat, with lack of connection to the peripheral conduction system, and one also had a fragmented His bundle. In addition premature aging of the summit of the ventricular septum may have reflected the long‐standing hemodynamic stresses of chronic bradycardia. This in turn resulted in trifasicuiar involvemenl of ihe conduction system leading to a shifting of the escape rhythm distally even‐tuating in a slower idio‐ventricular escape rhythm.
Permanent Transvenous Atrial Pacing After Heart Surgery
Authors: BOGNOLO DIEGO A. , VIJAYANAGAR R.R. , ECKSTEIN PAUL F. , JEFFERY DIANE L. , RENDINA ERINO , MORELLI MAURO
Published: July 2006

Permanent transvenous atrial “J” leads were successfully implanted in 10 patients whose atrial appendages had been previously amputated during heart surgery. Early and late lead performance was satisfactory.
Doxepin Induced Torsade De Pointes
Authors: STRASBERO BORIS , COELHO ALDO , WELCH WILLIAM , SWIRYN STEVEN , BAUERNFEIND ROBERT , ROSEN KENNETH
Published: July 2006

A case of torsade de pointes with normal QT interval secondary to the administration of small amounts of doxepin is presented. Electrophysiological studies during rechallenge with doxepin demonstrated replication of the patient's spontaneous arrhythmia. Evaluation of syncope in patients taking doxepin should include careful evaluation for torsade de pointes.
An Unusual PR Interval Alternans During 2:1 Atrio‐Ventricular Block
Authors: BRAT ALDO , FRANCHI FRANCO , PADELETTI LUIGI , MICHELUCCI ANTONIO , FANTINI FABIO
Published: July 2006

In a case of a 2:1 second degree A‐V block during sinus rhythm, PR intervals of two different durations occur, either separately or alternating beat‐by‐beat. The longer intervals are not caused by concealed conduction in the A‐V junction of the preceding blocked impulses and the shorter ones are not due to supernormal conduction induced by the blocked impulses. This primary PR interval alternans is alternating from a pothophysiological point of view; it only concerns every other impulse alternately traveling along the faster and slower A‐V functional pathway.
An Implantable Pulse Generator Indicating Asystole or Extreme Bradycardia
Authors: EDHAG K. OLOF , ELMQVIST HAKAN , VALLIN HANS O.
Published: July 2006

The design of a pacemaker which indicates the occurrence of significant bradyarrhythmia is described. Significant bradyarrhythmia is defined as either asystole for 6 seconds, bradycardia with three successive RR‐intervals greater than 2 seconds each, or five or more RR‐intervals of 2 seconds or more over a period of 25 seconds, but without three such intervals in succession. During bradyarrhythmia the generator initially stimulates at an interval of 2 seconds (30 per minute) and when the described criteria have been fulfilled the pacemaker automatically converts to a conventional ventricular inhibited pulse generator stimulating at a rate of 70 per minute.
Role of Specialized Conducting Fibers in the Genesis of “AV Nodal” Re‐entry Tachycardia
Authors: KERR CHARLES R. , BENSON D. WOODROW , GALLAGHER JOHN J.
Published: July 2006

Recent reports have suggested that an accessory bypass tract connecting the His bundle to the atrium (His‐atrial fiber) may form the retrograde limb of “AV nodal” re‐entry tachycardia (AVNRT). We studied 12 patients with AVNRT in whom the presence of an accessory atrioventricular fiber (Kent fiber) was excluded. We investigated the possibility of a His‐atrial (H‐A) fiber by examining the nature of retrograde conduction and by assessing the necessity of the atrium as a part of the re‐entry pathway. Retrograde conduction through the A V node had characteristics similar to retrograde conduction over a Kent bundle; that is, retrograde conduction times were short and did not vary. With echo beats (Ae) evoked during antegrade refractory period determination early premature beats resulted in prolongation of the AH interval with no change in HAe interval. During AVNRT the A‘H’:H‘A’ ratios ranged from 2.0–8.0 (mean 4.0 ± 1.8) and with changes in tachycardia cycle length the H'A interval remained constant. During retrograde refractory period determination, delay occurred below the AV node without change in the H‐A interval. Estimations of retrograde conduction times by all 3 methods were not significantly different (p > 0.2). The pattern of retrograde conduction suggests anatomical or functional specialized fibers as the retrograde limb of the tachycardia. The necessity of the atria as a part of the re‐entry circuit was assessed by the introduction of atrial premature beats (APBs) in the region of the atrial septum during AVNRT in 10 patients. APBs pre‐excited the atria by 40–140 ms without changing the cycle length of the tachycardia, providing strong evidence against the participation of an extranodal His‐atrial fiber in AVNRT, In conclusion, retrograde conduction during AVNRT appears to take place over a functional or anatomical specialized fiber within the AV node and not over an extranodal H‐A fiber.
Concealed Antidromic Re‐entrance During Rapid Atrial Pacing in the Wolff‐Parkinson‐White Syndrome
Authors: BOLLI ROBERTO , MAGRO SHARON A. , WYNDHAM CHRISTOPHER R.C.
Published: July 2006

In a patient with Wolff‐Parkinson‐White syndrome, rapid atrial pacing up to rates of 140/min resulted in A‐H prolongation; increases in rate up to 200/min, however, failed to lengthen A‐H further. The delta‐H interval increased as rate rose to 120/min, but remained stable thereafter. These and other findings suggest retrograde activation of the His bundle via the accessory pathway at rates greater than 140/min. Such a phenomenon: 1) prevents initiation of PSVT with atrial pacing; 2) prevents one from determining the anterograde block rate of the AV node; 3) represents concealed antidromic re‐entrance, which may theoretically lead to antidromic re‐entrant PSVT.