La frequence cardiaque determinee par la temperature centrale. Les stimuiateurs cardiaques a freq... more La frequence cardiaque determinee par la temperature centrale. Les stimuiateurs cardiaques a frequence fixe ne restaurent pas la fonction hemodynamique normale. Puisque un pourcentage eieve de patients porteurs d'un stimulateur cardiaque a des anomalies auriculaires. un autre moyen de "piloter" le pacemaker est presente: celui de ia temperature du sang dans I'oreiilette droite. Les sondes a enregistrement thermique mesurent la variation de temp^.rature pendant I'exercice et peuvent servir de guide pour determiner la frequence cardiaque optimaie. GRIFFIN, J.C, ETAL.: Central body temperature as a guide to optimal heart rate. Studies in man suggest thai fixed-rate artificial pacemakers do not return hemodynamic function to normal, since the principal mechanism for the increase in cardiac output with exercise, increased heart rate, is not restored. Special pacemakers are available that can detect atrial activity and pace the ventricles in coordination, but nearly half of the patients receiving artificial pacemakers have abnormal atrial function (atriai fibrillation, sick sinus syndrome}. This study examined the effects of exercise on the temperature of blood returning to the right atrium. Precision thermistors, placed in the right hearts of conscious dogs, recorded temperature increases of 1"C (range 0.4-1.5''C} during submaximal treadmill exercise. Temperature change correlated well with work load and changes in heart rate.
Ad(lr(\ss for rf^prinl.s: ferry C. Griffin. M.D., DGparlment of MfjiUcine. Section of Cardioloj^y... more Ad(lr(\ss for rf^prinl.s: ferry C. Griffin. M.D., DGparlment of MfjiUcine. Section of Cardioloj^y, Baytcir Collfige of Medicine,
L'implantation du defibrillateur automatique par thoracotomie sous costale. Le defibriUateur auto... more L'implantation du defibrillateur automatique par thoracotomie sous costale. Le defibriUateur automatique impJanlabJe est un net progres en ce qui concerne ia Iherapeutique de certains patients presentanfs des tachycardies et/ou /ibrillations ventricuJaires. La technique inifiale necessitait Ia pose de deux electrodes transveineuses ef d'une epicardique par thoracofomie gauche. Nous avons d^veloppe avec succes une approche puremenf epicardique d I'aide d'une thoracotowie sous costale gauche. L'experience passee de I'impiantation des pacemakers epicardiques par cette voie suggerait que ceile ci serait bonne pour I'impiantation du de/ibrillafeur automatique. Les resultats inifiaux nous encouragent d poursuivre son utilisation. LAWRIE, G.M., ET AL.: Epicardial implantation of the automatic implantable defibrillator by left subcostal thoracotomy. The automatic implantable de/ibrillator is a valuable addition to the management of certain patients with ventricular tachycardia and/or fibrillation. The original technique required placement of two transvenous electrodes and an epicardial electrode via a left thoracotomy. We have successfully developed an all-epicardial approach using a le/( subcostal thoracotomy. Previous experience with epicardial pacemaker implantation hy this approach suggested it would he a good technique for implantation of the automatic de/ibrillator. Early results with this approach have encouraged its continued use. automatic de/ibrillator, implant techniques
Results of Antitachycardia Pacing in Patients with Supraventricular Tachycardia. Between 1979 and... more Results of Antitachycardia Pacing in Patients with Supraventricular Tachycardia. Between 1979 and 1984 the Cybertach-60, {Intermedics, Inc. Model 262-01}, a programmable, automatic antitachycardia pacemaker was implanted in 31 patients who had drug-re/ractory supraventricular tachycardia (SVTJ. The patients have been followed for a total of 64-108 (mean 84 months). All patients were symptomatic and had /ailed two or more drugs and six patients had required prior DC cardioversion. The mechanism o/supraventricuJar tachycardia was atrioventricular (AV) nodal reentry in six patients, AV reentry in four patients, and atrial tachycardia in one patient. Preoperatively all patients had reJiable termination of the tachycardia without induction of atrial jibriliation by pacing methods available to Cybertach-60. Postimplant, Cybertach-60 reliably terminated all episodes o/tachycardia without ancillary drug therapy. Nevertheless, at iong-term foUow-up antitachycardia pacing was effective and safe in the minority (36%}. with only four patients out of eleven still using a pacemaker for supraventricu/ar tachycardia. One of these four patients required additional drug therapy. In one of the patients, the Cyhertach-60 was replaced after 78 months by a more advanced device, (Intertach, Intermedics, Inc.) because of a depleted Cybertach-60 battery. In seven patients who no longer use antitachycardia pacing for termination of tachycardia, one patient developed atrial jibrilJation during tachycardia termination (at 58 months postimplant). Three patients experienced induction of tachycardia or atrial ^briiiation by the pacemaker due to undersensing of sinus P waves (at 36, 48, and 51 months}. One patient had inappropriate rate detection while in sinus rhythm triggering the tachycardia termination burst from the pacemaker and subsequent SVT induction. Although pace termination of supraventricuJar tachycardia was effective in two patients, they chose elective ablation (AV nodal and accessory pathway, respectively, at 74 and 6 months) due to frequent symptomatic SVT. (PACE, VoJ. 12, fune 1989} antitachycardia pacing, supraventricular tachycardia Address for reprints: Ingela Schntttger, M.D., Cardiology Divi-i r L i sion.
MORADY, F., ET AL.: Results of Catheter Ablation of Ventricular Tachycardia Using Direct Current ... more MORADY, F., ET AL.: Results of Catheter Ablation of Ventricular Tachycardia Using Direct Current Shocks. Thirty-three patients with recurrent ventricular tachycardia (VT) underwent catheter ahlation with direct-current shocks. One to four shocks 0/ 100-300 joules were deiivered to the presumed VT exit sites as identified by endocardiai mapping and pace mapping. Fifteen patients (45%) had no recurrence 0/ symptomatic VT during a follow-up interval of 15.5 ± 10 months (mean ± standard deviation). Five patients experienced six nonfatal complications (netv VTor ventricular jibriiJation, transient neuroiogical deficit, atrioventricuiar hlock, brachial artery thrombosis). In conclusion, catheter ablation in selected patients with recurrent VT has the potential for preventing recurrences 0/VT over the long-term and is relatively safe. (PACE, Vol. 12, January Part II 1989) ventricuiar tachycardia, endocardial mapping, catheter ablation
TOMASELLI, G.F., ET AL.: Morphologic differences of the endocardial electrogram in beats of sinus... more TOMASELLI, G.F., ET AL.: Morphologic differences of the endocardial electrogram in beats of sinus and ventricular origin. The lack of accurate arrhythmia detection and identi/ication is one 0/ the mojior obstacles to improvement in the e_^cacy of antitachycardia devices. We evaluated a method for detection 0/ beats of ventricular origin compared to sinus rhythm based on the morphology of the endocardia} electrogram. In order to compare mechanically induced ventricular beats to normal sinus beats, endocardial electrograms from a standard pacing electrode were recorded from eight open-chested dogs. Time and frequency domain features analyzed included peak-to-peak amplitude (AMP), maximal slew rate (dV/dTJ. and frequency content (-3 dB downpoint). Quantitative morphologic comparison of the waveforms was performed using standard correlation and by the absolute area of difference between the waveform and a sinus beat template. The AMP and dV/dT for a group of ventricular beats did not differ signijicantly from beats of sinus origin. In the unipolar conjigurution -3 dBfor ventricular beats was significantly different from sinus beats (p -.01), but overlap occurred in three of eight cases. Conversely, using either method of assessment of morphological differences, all ventricular beats could be identified without overlapping the values for normal beats. We concluded that morphologic analysis of the endocardia] electrogram by such methods may be a highly accurate means of distinguishing between beats of sinus and ventricular origins. This technique may also be applicable to the problem of automatic rhythm identification hy implanted devices.
Journal of the American College of Cardiology, 1991
In order to assure appropriate application, safe performance and judicious interpretation of the ... more In order to assure appropriate application, safe performance and judicious interpretation of the complex procedures involv.d in clinical cardiac electrophysiology, and to guarantee correct application of the wide range of antiarrhythmic therapies now available, a well defined program of training is necessary. The American Board of Internal Medicine 'ABIMI has recognized the need for specific training in electrophysiology and will offer an examination for certification in clinical cardiac electrophysiology in 1992 . Subspecialty certification in cardiovascular diseases previously required 2 and currently requires 3 yeas of training . The ABIM has mandated that an additional year of clinical training in cardiac electrophysiology will he required for eligibility to take the certifying examination in clectrophysiologs • The purpose of this nennn is to cslublish guidelines far training programs in clinical cardiac electrophysiology . The aim of the program is to provide the trainee with a broad base of knowledge and experience in normal and abnormal cardiac electrophysiology and arrhythmias. The trainee should develop knowledge and practical experience in the following areas :
Journal of the American College of Cardiology, 1988
Fifty patients with recurrent sustained symptomatic ventricular tachycardia (43 patients) or vent... more Fifty patients with recurrent sustained symptomatic ventricular tachycardia (43 patients) or ventricular fibrillation (7 patients) resistant to a mean of 2.8 + 1.4 antiarrhythmic drugs were treated with sotalol, a beta-adrenergic receptor antagonist, and 45 underwent invasive electrophysiologic testing before and after sotalol therapy. The arrhythmia became noninducible in 10, was slower and hemodynamically well tolerated in 12 and was poorly tolerated in 23. Four patients were empirically treated with long-term administration of oral sotalol as were 21 patients who either had noninducible arrhythmia (10 patients) or had hemodynamically stable ventricular tachycardia (11 patients). In these 25 patients treated with long-term administration of sotalol, there was no recurrence of ventricular tachycardia in the group with noninducible arrhythmia, whereas 37% of patients with inducible ventricular tachycardia had new ventricular tachycardia or sudden death. Programmed ventricular stimulation with up to three extrastimuli proved to be an excellent predictor of drug efficacy and a good predictor of inefficacy. A positive prior response to amiodarone was not a reliable indicator of a positive response to sotalol. Side effects included those attributed to both beta-adrenergic blockade as well as proarrhythmic effects. The latter were observed in two of four patients with a QT interval greater than 600 ms. Sotalol was found to be effective therapy for a subset of patients with ventricular tachycardia unresponsive to type IA drugs.
Journal of the American College of Cardiology, 1990
Ire&d with lkcainide for nlrioventricular (Al') r,,n,ranl tarhycardia were rludied to evaluate th... more Ire&d with lkcainide for nlrioventricular (Al') r,,n,ranl tarhycardia were rludied to evaluate the mechanism of hlcbycmdia induribilily af,er boprotarenol and ,be whe of bopmierenol cballellge a5 a predictor Of rpo",aneous arrbylbmia recwrmce. Seventeen patients underwen, eke. ,mpbysialogic study beEare and itfter oral Rwainide adminis,,ation and aRer the addition al isoproterenol lo Roeeirdde. No patient bad indoribla sustaimd supravenhic. alar trhycardia alter Becainide alone. Two pntients bad inducible wtimd and six bad inducible nonrvstind lsrhycardis afler iroprolerenol was added lo Reesinide. Tke padents were then fdlove4 up on Ike same Rerainide dose they received al the time of ,he eleclropbyrialogic shldy. Fimffngs: 1) Fkainide ,reahnen, prolonged HV and V.4 k&n&, and ,be addilioo of isopra,eRnol did not a&, ulac vtibla. 2) Isopmterend shortened anlemgmde and Mmgrade Mmk cycle length and the rdmclory period of ,he amess,ry pdbway ,nd Le AV node. It alsa decremed tbe tacbywdia cycle kngth, an effect tba, was due z4c4y b Fkcainide has been rcpaned (I-6) to be cffectwe in preventing the induction of atrioventricular (AV) reenWam supravenfricular fackycardia after either intravenous or long-term administration. However, spataneous supraventricular tachycardia may recur in patients with an accessory pathway who have no inducible tachycardia when tested during oral Aecainidr therapy (1.2). We studied the elechophysiologic effects oi isoprolerenol io patients treated with fkcainide for AV reentrant tacbycardia to evalule ihe effects of the drug on the accessory pathway and AV node. the mechanism of lackycardia inducibility after iroprolere-no1 and the value of isapmterenol challenge as a predicror of spontaneous arrhythmia recurrence. Methods Study patienls. Of 20 patients with inducible sustained orthodromic supravenfricular tacbycardia at baseline study. 3 sriil bad inducible sustained tacbycardia after long-ferm oral Recainide administration. The other 17 pafienfs who no longer had mducihle sustained tacbycardia after Recainide were restudied after isoprolerenol challenge and :re rhe subjects of this repon. Electrophysiologic study. Baseline electropbysialogic studies were perfomxd with patients in the postabsorptive state at least five half-lives after all antiarrhytkmic medications had been disconhnued. Quadrapolar electrode cathe-
To examine the electrocerebral and clinical accompaniments of syncope associated with malignant v... more To examine the electrocerebral and clinical accompaniments of syncope associated with malignant ventricular cardiac arrhythmias. Survey of clinical and electroencephalographic changes during induced cardiac dysrhythmia. Clinical electrophysiology laboratory of a university medical center. Fourteen patients with automatic cardioverter defibrillators due to previous cardiac arrest or life-threatening cardiac arrhythmia. Deliberate induction of cardiac dysrhythmia for routine, postoperative testing of the automatic implantable cardioverter defibrillator. Continuous electrocardiographic, electroencephalographic, and video recording. Twenty-two episodes of ventricular tachycardia or fibrillation, lasting 15 to 126 seconds, were induced with definite loss of consciousness in 15 instances and probable loss in 2. In 10 episodes, there were motor accompaniments to the unconsciousness characterized by tonic activity or irregular muscle twitching. On regaining consciousness, patients were usually obtunded or confused for up to 30 seconds, depending on duration of induced cardiac dysrhythmia and unconsciousness. Electroencephalographic changes were variable. Background slowing was usually followed by relative loss of electrocerebral activity. In 2 patients, attenuation of background electrocerebral activity followed little or no change in background rhythms. In 5 episodes, electroencephalograms showed no change before loss of consciousness, but slowed thereafter in 4. Conspicuous motor activity may accompany syncope due to malignant ventricular arrhythmia and complicate the clinical distinction of syncope from seizures. Post-syncopal confusion generally lasts for less than 30 seconds. The electroencephalographic accompaniments of acute cerebral anoxia leading to syncope, and of the motor accompaniments of syncope, are more variable than previously appreciated, but electrographic seizure activity does not occur.
Right ventricular epicardial ventricular fibrillation threshold was determined during paced supra... more Right ventricular epicardial ventricular fibrillation threshold was determined during paced supraventricular rhythm using 100 hertz trains of stimuli at 15 minute intervals in dogs before, during and after a 90 minute infusion of tocainide, an orally effective antiarrhythmic drug. With each ventricular fibrillation threshold determination, simultaneous blood samples were obtained for determination of drug concentration. Concentration-response curves for dogs receiving tocainide showed that in general there is no measurabte increase in ventricular fibrillation threshold at concentrations of less than 6 to 10 pg/ml. At 10 pg/ml the mean ventricular flbrtllation threshold increased 26 percent jrange 14 to 67 percent), at 15 Mg/ml53 percent (range 26 to 111 percent) and at 20 pg/ml 71 percent (range 37 to 143 percent). There was a wide range of interanimal sensitivity to tocainide, gut for each animal there was a significant relation between increase in ventricular fibrillation threshold and log plasma concentration.
Journal of the American College of Cardiology, May 1, 1994
OBJECTIVES: The purpose of this study was to evaluate the efficacy and safety of radiofrequency c... more OBJECTIVES: The purpose of this study was to evaluate the efficacy and safety of radiofrequency catheter ablation for the treatment of supraventricular tachycardias in an elderly (> or = 70 years of age) group of patients.BACKGROUND: Supraventricular tachycardias are the most common form of cardiac arrhythmia and affect all age groups. Although usually well tolerated in youth, supraventricular tachycardias may be associated with disabling symptoms and have life-threatening potential in the elderly. In addition, antiarrhythmic agents are less well tolerated and may be associated with a higher incidence of toxicity in the elderly.METHODS: From May 1989 to March 1993, 454 patients underwent a radiofrequency catheter ablation procedure at the University of California, San Francisco, for the treatment of symptomatic supraventricular tachycardia. Sixty-seven of these patients were > or = 70 years of age and constituted the study group. Patients underwent one of the following catheter ablation procedures: complete atrioventricular (AV) junctional ablation for ventricular rate control in patients with atrial fibrillation (37 patients), AV node modification for the treatment of AV node reentrant tachycardia (17 patients), accessory pathway ablation (9 patients), ablation of the "slow zone" to cure atrial flutter (4 patients) and atrial tachycardia ablation (1 patient). One patient underwent ablation for both AV node reentrant tachycardia and atrial flutter.RESULTS: Success was achieved in 67 (98.5%) of 68 ablation procedures. There were no procedural or early deaths. The overall complication rate was 7.4%, and only one patient (1.5%) had long-term sequelae (permanent cardiac pacing for complete heart block). At a mean (+/- SD) follow-up of 22.1 +/- 12.9 months, 63 (94%) of 67 patients were alive, with no antiarrhythmic agents for the treatment of their presenting arrhythmia.CONCLUSIONS: In this series radiofrequency catheter ablation appears to be an effective and safe treatment option for elderly patients (> or = 70 years of age) with a variety of symptomatic, drug-resistant supraventricular tachycardias. Because of the high incidence of severe symptoms associated with tachycardic episodes, the expense and the possible severe proarrhythmic problems associated with antiarrhythmic medications in this age group, catheter ablation may be considered an early rather than a "last resort" treatment option.
La frequence cardiaque determinee par la temperature centrale. Les stimuiateurs cardiaques a freq... more La frequence cardiaque determinee par la temperature centrale. Les stimuiateurs cardiaques a frequence fixe ne restaurent pas la fonction hemodynamique normale. Puisque un pourcentage eieve de patients porteurs d'un stimulateur cardiaque a des anomalies auriculaires. un autre moyen de "piloter" le pacemaker est presente: celui de ia temperature du sang dans I'oreiilette droite. Les sondes a enregistrement thermique mesurent la variation de temp^.rature pendant I'exercice et peuvent servir de guide pour determiner la frequence cardiaque optimaie. GRIFFIN, J.C, ETAL.: Central body temperature as a guide to optimal heart rate. Studies in man suggest thai fixed-rate artificial pacemakers do not return hemodynamic function to normal, since the principal mechanism for the increase in cardiac output with exercise, increased heart rate, is not restored. Special pacemakers are available that can detect atrial activity and pace the ventricles in coordination, but nearly half of the patients receiving artificial pacemakers have abnormal atrial function (atriai fibrillation, sick sinus syndrome}. This study examined the effects of exercise on the temperature of blood returning to the right atrium. Precision thermistors, placed in the right hearts of conscious dogs, recorded temperature increases of 1"C (range 0.4-1.5''C} during submaximal treadmill exercise. Temperature change correlated well with work load and changes in heart rate.
Ad(lr(\ss for rf^prinl.s: ferry C. Griffin. M.D., DGparlment of MfjiUcine. Section of Cardioloj^y... more Ad(lr(\ss for rf^prinl.s: ferry C. Griffin. M.D., DGparlment of MfjiUcine. Section of Cardioloj^y, Baytcir Collfige of Medicine,
L'implantation du defibrillateur automatique par thoracotomie sous costale. Le defibriUateur auto... more L'implantation du defibrillateur automatique par thoracotomie sous costale. Le defibriUateur automatique impJanlabJe est un net progres en ce qui concerne ia Iherapeutique de certains patients presentanfs des tachycardies et/ou /ibrillations ventricuJaires. La technique inifiale necessitait Ia pose de deux electrodes transveineuses ef d'une epicardique par thoracofomie gauche. Nous avons d^veloppe avec succes une approche puremenf epicardique d I'aide d'une thoracotowie sous costale gauche. L'experience passee de I'impiantation des pacemakers epicardiques par cette voie suggerait que ceile ci serait bonne pour I'impiantation du de/ibrillafeur automatique. Les resultats inifiaux nous encouragent d poursuivre son utilisation. LAWRIE, G.M., ET AL.: Epicardial implantation of the automatic implantable defibrillator by left subcostal thoracotomy. The automatic implantable de/ibrillator is a valuable addition to the management of certain patients with ventricular tachycardia and/or fibrillation. The original technique required placement of two transvenous electrodes and an epicardial electrode via a left thoracotomy. We have successfully developed an all-epicardial approach using a le/( subcostal thoracotomy. Previous experience with epicardial pacemaker implantation hy this approach suggested it would he a good technique for implantation of the automatic de/ibrillator. Early results with this approach have encouraged its continued use. automatic de/ibrillator, implant techniques
Results of Antitachycardia Pacing in Patients with Supraventricular Tachycardia. Between 1979 and... more Results of Antitachycardia Pacing in Patients with Supraventricular Tachycardia. Between 1979 and 1984 the Cybertach-60, {Intermedics, Inc. Model 262-01}, a programmable, automatic antitachycardia pacemaker was implanted in 31 patients who had drug-re/ractory supraventricular tachycardia (SVTJ. The patients have been followed for a total of 64-108 (mean 84 months). All patients were symptomatic and had /ailed two or more drugs and six patients had required prior DC cardioversion. The mechanism o/supraventricuJar tachycardia was atrioventricular (AV) nodal reentry in six patients, AV reentry in four patients, and atrial tachycardia in one patient. Preoperatively all patients had reJiable termination of the tachycardia without induction of atrial jibriliation by pacing methods available to Cybertach-60. Postimplant, Cybertach-60 reliably terminated all episodes o/tachycardia without ancillary drug therapy. Nevertheless, at iong-term foUow-up antitachycardia pacing was effective and safe in the minority (36%}. with only four patients out of eleven still using a pacemaker for supraventricu/ar tachycardia. One of these four patients required additional drug therapy. In one of the patients, the Cyhertach-60 was replaced after 78 months by a more advanced device, (Intertach, Intermedics, Inc.) because of a depleted Cybertach-60 battery. In seven patients who no longer use antitachycardia pacing for termination of tachycardia, one patient developed atrial jibrilJation during tachycardia termination (at 58 months postimplant). Three patients experienced induction of tachycardia or atrial ^briiiation by the pacemaker due to undersensing of sinus P waves (at 36, 48, and 51 months}. One patient had inappropriate rate detection while in sinus rhythm triggering the tachycardia termination burst from the pacemaker and subsequent SVT induction. Although pace termination of supraventricuJar tachycardia was effective in two patients, they chose elective ablation (AV nodal and accessory pathway, respectively, at 74 and 6 months) due to frequent symptomatic SVT. (PACE, VoJ. 12, fune 1989} antitachycardia pacing, supraventricular tachycardia Address for reprints: Ingela Schntttger, M.D., Cardiology Divi-i r L i sion.
MORADY, F., ET AL.: Results of Catheter Ablation of Ventricular Tachycardia Using Direct Current ... more MORADY, F., ET AL.: Results of Catheter Ablation of Ventricular Tachycardia Using Direct Current Shocks. Thirty-three patients with recurrent ventricular tachycardia (VT) underwent catheter ahlation with direct-current shocks. One to four shocks 0/ 100-300 joules were deiivered to the presumed VT exit sites as identified by endocardiai mapping and pace mapping. Fifteen patients (45%) had no recurrence 0/ symptomatic VT during a follow-up interval of 15.5 ± 10 months (mean ± standard deviation). Five patients experienced six nonfatal complications (netv VTor ventricular jibriiJation, transient neuroiogical deficit, atrioventricuiar hlock, brachial artery thrombosis). In conclusion, catheter ablation in selected patients with recurrent VT has the potential for preventing recurrences 0/VT over the long-term and is relatively safe. (PACE, Vol. 12, January Part II 1989) ventricuiar tachycardia, endocardial mapping, catheter ablation
TOMASELLI, G.F., ET AL.: Morphologic differences of the endocardial electrogram in beats of sinus... more TOMASELLI, G.F., ET AL.: Morphologic differences of the endocardial electrogram in beats of sinus and ventricular origin. The lack of accurate arrhythmia detection and identi/ication is one 0/ the mojior obstacles to improvement in the e_^cacy of antitachycardia devices. We evaluated a method for detection 0/ beats of ventricular origin compared to sinus rhythm based on the morphology of the endocardia} electrogram. In order to compare mechanically induced ventricular beats to normal sinus beats, endocardial electrograms from a standard pacing electrode were recorded from eight open-chested dogs. Time and frequency domain features analyzed included peak-to-peak amplitude (AMP), maximal slew rate (dV/dTJ. and frequency content (-3 dB downpoint). Quantitative morphologic comparison of the waveforms was performed using standard correlation and by the absolute area of difference between the waveform and a sinus beat template. The AMP and dV/dT for a group of ventricular beats did not differ signijicantly from beats of sinus origin. In the unipolar conjigurution -3 dBfor ventricular beats was significantly different from sinus beats (p -.01), but overlap occurred in three of eight cases. Conversely, using either method of assessment of morphological differences, all ventricular beats could be identified without overlapping the values for normal beats. We concluded that morphologic analysis of the endocardia] electrogram by such methods may be a highly accurate means of distinguishing between beats of sinus and ventricular origins. This technique may also be applicable to the problem of automatic rhythm identification hy implanted devices.
Journal of the American College of Cardiology, 1991
In order to assure appropriate application, safe performance and judicious interpretation of the ... more In order to assure appropriate application, safe performance and judicious interpretation of the complex procedures involv.d in clinical cardiac electrophysiology, and to guarantee correct application of the wide range of antiarrhythmic therapies now available, a well defined program of training is necessary. The American Board of Internal Medicine 'ABIMI has recognized the need for specific training in electrophysiology and will offer an examination for certification in clinical cardiac electrophysiology in 1992 . Subspecialty certification in cardiovascular diseases previously required 2 and currently requires 3 yeas of training . The ABIM has mandated that an additional year of clinical training in cardiac electrophysiology will he required for eligibility to take the certifying examination in clectrophysiologs • The purpose of this nennn is to cslublish guidelines far training programs in clinical cardiac electrophysiology . The aim of the program is to provide the trainee with a broad base of knowledge and experience in normal and abnormal cardiac electrophysiology and arrhythmias. The trainee should develop knowledge and practical experience in the following areas :
Journal of the American College of Cardiology, 1988
Fifty patients with recurrent sustained symptomatic ventricular tachycardia (43 patients) or vent... more Fifty patients with recurrent sustained symptomatic ventricular tachycardia (43 patients) or ventricular fibrillation (7 patients) resistant to a mean of 2.8 + 1.4 antiarrhythmic drugs were treated with sotalol, a beta-adrenergic receptor antagonist, and 45 underwent invasive electrophysiologic testing before and after sotalol therapy. The arrhythmia became noninducible in 10, was slower and hemodynamically well tolerated in 12 and was poorly tolerated in 23. Four patients were empirically treated with long-term administration of oral sotalol as were 21 patients who either had noninducible arrhythmia (10 patients) or had hemodynamically stable ventricular tachycardia (11 patients). In these 25 patients treated with long-term administration of sotalol, there was no recurrence of ventricular tachycardia in the group with noninducible arrhythmia, whereas 37% of patients with inducible ventricular tachycardia had new ventricular tachycardia or sudden death. Programmed ventricular stimulation with up to three extrastimuli proved to be an excellent predictor of drug efficacy and a good predictor of inefficacy. A positive prior response to amiodarone was not a reliable indicator of a positive response to sotalol. Side effects included those attributed to both beta-adrenergic blockade as well as proarrhythmic effects. The latter were observed in two of four patients with a QT interval greater than 600 ms. Sotalol was found to be effective therapy for a subset of patients with ventricular tachycardia unresponsive to type IA drugs.
Journal of the American College of Cardiology, 1990
Ire&d with lkcainide for nlrioventricular (Al') r,,n,ranl tarhycardia were rludied to evaluate th... more Ire&d with lkcainide for nlrioventricular (Al') r,,n,ranl tarhycardia were rludied to evaluate the mechanism of hlcbycmdia induribilily af,er boprotarenol and ,be whe of bopmierenol cballellge a5 a predictor Of rpo",aneous arrbylbmia recwrmce. Seventeen patients underwen, eke. ,mpbysialogic study beEare and itfter oral Rwainide adminis,,ation and aRer the addition al isoproterenol lo Roeeirdde. No patient bad indoribla sustaimd supravenhic. alar trhycardia alter Becainide alone. Two pntients bad inducible wtimd and six bad inducible nonrvstind lsrhycardis afler iroprolerenol was added lo Reesinide. Tke padents were then fdlove4 up on Ike same Rerainide dose they received al the time of ,he eleclropbyrialogic shldy. Fimffngs: 1) Fkainide ,reahnen, prolonged HV and V.4 k&n&, and ,be addilioo of isopra,eRnol did not a&, ulac vtibla. 2) Isopmterend shortened anlemgmde and Mmgrade Mmk cycle length and the rdmclory period of ,he amess,ry pdbway ,nd Le AV node. It alsa decremed tbe tacbywdia cycle kngth, an effect tba, was due z4c4y b Fkcainide has been rcpaned (I-6) to be cffectwe in preventing the induction of atrioventricular (AV) reenWam supravenfricular fackycardia after either intravenous or long-term administration. However, spataneous supraventricular tachycardia may recur in patients with an accessory pathway who have no inducible tachycardia when tested during oral Aecainidr therapy (1.2). We studied the elechophysiologic effects oi isoprolerenol io patients treated with fkcainide for AV reentrant tacbycardia to evalule ihe effects of the drug on the accessory pathway and AV node. the mechanism of lackycardia inducibility after iroprolere-no1 and the value of isapmterenol challenge as a predicror of spontaneous arrhythmia recurrence. Methods Study patienls. Of 20 patients with inducible sustained orthodromic supravenfricular tacbycardia at baseline study. 3 sriil bad inducible sustained tacbycardia after long-ferm oral Recainide administration. The other 17 pafienfs who no longer had mducihle sustained tacbycardia after Recainide were restudied after isoprolerenol challenge and :re rhe subjects of this repon. Electrophysiologic study. Baseline electropbysialogic studies were perfomxd with patients in the postabsorptive state at least five half-lives after all antiarrhytkmic medications had been disconhnued. Quadrapolar electrode cathe-
To examine the electrocerebral and clinical accompaniments of syncope associated with malignant v... more To examine the electrocerebral and clinical accompaniments of syncope associated with malignant ventricular cardiac arrhythmias. Survey of clinical and electroencephalographic changes during induced cardiac dysrhythmia. Clinical electrophysiology laboratory of a university medical center. Fourteen patients with automatic cardioverter defibrillators due to previous cardiac arrest or life-threatening cardiac arrhythmia. Deliberate induction of cardiac dysrhythmia for routine, postoperative testing of the automatic implantable cardioverter defibrillator. Continuous electrocardiographic, electroencephalographic, and video recording. Twenty-two episodes of ventricular tachycardia or fibrillation, lasting 15 to 126 seconds, were induced with definite loss of consciousness in 15 instances and probable loss in 2. In 10 episodes, there were motor accompaniments to the unconsciousness characterized by tonic activity or irregular muscle twitching. On regaining consciousness, patients were usually obtunded or confused for up to 30 seconds, depending on duration of induced cardiac dysrhythmia and unconsciousness. Electroencephalographic changes were variable. Background slowing was usually followed by relative loss of electrocerebral activity. In 2 patients, attenuation of background electrocerebral activity followed little or no change in background rhythms. In 5 episodes, electroencephalograms showed no change before loss of consciousness, but slowed thereafter in 4. Conspicuous motor activity may accompany syncope due to malignant ventricular arrhythmia and complicate the clinical distinction of syncope from seizures. Post-syncopal confusion generally lasts for less than 30 seconds. The electroencephalographic accompaniments of acute cerebral anoxia leading to syncope, and of the motor accompaniments of syncope, are more variable than previously appreciated, but electrographic seizure activity does not occur.
Right ventricular epicardial ventricular fibrillation threshold was determined during paced supra... more Right ventricular epicardial ventricular fibrillation threshold was determined during paced supraventricular rhythm using 100 hertz trains of stimuli at 15 minute intervals in dogs before, during and after a 90 minute infusion of tocainide, an orally effective antiarrhythmic drug. With each ventricular fibrillation threshold determination, simultaneous blood samples were obtained for determination of drug concentration. Concentration-response curves for dogs receiving tocainide showed that in general there is no measurabte increase in ventricular fibrillation threshold at concentrations of less than 6 to 10 pg/ml. At 10 pg/ml the mean ventricular flbrtllation threshold increased 26 percent jrange 14 to 67 percent), at 15 Mg/ml53 percent (range 26 to 111 percent) and at 20 pg/ml 71 percent (range 37 to 143 percent). There was a wide range of interanimal sensitivity to tocainide, gut for each animal there was a significant relation between increase in ventricular fibrillation threshold and log plasma concentration.
Journal of the American College of Cardiology, May 1, 1994
OBJECTIVES: The purpose of this study was to evaluate the efficacy and safety of radiofrequency c... more OBJECTIVES: The purpose of this study was to evaluate the efficacy and safety of radiofrequency catheter ablation for the treatment of supraventricular tachycardias in an elderly (> or = 70 years of age) group of patients.BACKGROUND: Supraventricular tachycardias are the most common form of cardiac arrhythmia and affect all age groups. Although usually well tolerated in youth, supraventricular tachycardias may be associated with disabling symptoms and have life-threatening potential in the elderly. In addition, antiarrhythmic agents are less well tolerated and may be associated with a higher incidence of toxicity in the elderly.METHODS: From May 1989 to March 1993, 454 patients underwent a radiofrequency catheter ablation procedure at the University of California, San Francisco, for the treatment of symptomatic supraventricular tachycardia. Sixty-seven of these patients were > or = 70 years of age and constituted the study group. Patients underwent one of the following catheter ablation procedures: complete atrioventricular (AV) junctional ablation for ventricular rate control in patients with atrial fibrillation (37 patients), AV node modification for the treatment of AV node reentrant tachycardia (17 patients), accessory pathway ablation (9 patients), ablation of the "slow zone" to cure atrial flutter (4 patients) and atrial tachycardia ablation (1 patient). One patient underwent ablation for both AV node reentrant tachycardia and atrial flutter.RESULTS: Success was achieved in 67 (98.5%) of 68 ablation procedures. There were no procedural or early deaths. The overall complication rate was 7.4%, and only one patient (1.5%) had long-term sequelae (permanent cardiac pacing for complete heart block). At a mean (+/- SD) follow-up of 22.1 +/- 12.9 months, 63 (94%) of 67 patients were alive, with no antiarrhythmic agents for the treatment of their presenting arrhythmia.CONCLUSIONS: In this series radiofrequency catheter ablation appears to be an effective and safe treatment option for elderly patients (> or = 70 years of age) with a variety of symptomatic, drug-resistant supraventricular tachycardias. Because of the high incidence of severe symptoms associated with tachycardic episodes, the expense and the possible severe proarrhythmic problems associated with antiarrhythmic medications in this age group, catheter ablation may be considered an early rather than a "last resort" treatment option.
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Papers by Jerry Griffin