- Email: [email protected]
Cryosurgical ablation of the AV node-his bundle: Results and follow-up of 19 cases
ABSTRACTS
THE INCIDENCE, DETERMINANTS AND SIGNIFICANCE OF RETROGRADELY FUNCTIONAL ATRIOVENTRICULAR NODAL BYPASS TRACTS ~ A . Gomes, MD, FACC; Malkiat S. Dhatt, MD,•FACC; Anthony N. Dam--~to~ MD~ ~asood Akhtar MD, FACe; Carol Holder, RN, U. S. Public Health Service Hospital, Staten Island, New York The incidence, determinants and significance of retrogradely functional AV nodal bypass tracts (BT) remains unclear. Of i00 patients (pts) with His bundle electrograms and complete anterograde (ant) and retrograde (rat) studies in whom ventricular atrial (VA) BT's were excluded, 18 pts demonstrated electrophysiologic (E) evidence for selective rat utilization of AV nodal BT's characterized by: I) short (36 + 9 msec; mean + SD; range = 25-50 msec) and constant H2 A2 intervals during rat refractory periods (RP) studies which w e r e s i g n i f i c a n t l y ( p < •001) shorter than the AH intervals (78 + 20 msec); 2)significantly (P < .025) better VA than AV conduction (ventricular pacing cycle length with i:i VA = 367 ~ 42 msec;atrial pacing cycle length with I:I AV conduction =•410 ~ 72 msec); 3) significantly (p < .025) shorter rat functional RP of the VA conducting system than the AV conducting system and 4) the rat effective RP of the AV node Was not attained in any of the 18 pts. 14/18 pts (77%) had a history of palpitations and in 13/18 pts (72%) single echoes and/or sustained reentrant supraventricular tachycardia (SVT)could be initiated during E studies. During SVT all 13 pts had short (36 + 9 msec) and constant conduction time in the rat limb(H---Ae intervals) which were identical to the H2 A2 intervals. In conclusion rat AV nodal BT's: i) are functional in 18% of pts and are associated with a high incidence of SVT; 2) provide the substrata in the • initiation and sustenance of reentrant SVT(AV node-His as ant and BT as rat limb) and 3) E findings suggest Hisatrial location Of these BT's.
RE-ENTRY DUE TO LONGITUDINAL DISSOCIATION IN THE HIS BUNDLE (BH) N a r a s i m h a n S h a n t h a ~ M.D., F.A.C.C., Paolo Alboni, M.D., William Towne, M.D., F.A.C.C., Onkar S. Narula, M.D., F.A.C.C.; Cook County Hospital, Chicago, Illinois and The Chicago Medical School, Chicago, Illinois.
ELECTROPHYSIOLOGICAL IDENTIFICATION OF THE COEXISTENCE OF DUAL ATRIOVENTRICULAR NODAL PATHWAY CONDUCTION AND ANOMALOUS BYPASS TRACTS Ruey J. Sung, MD, FACC; Agustin Castellanos,MD, FACC; Stephen M. Mallon, MD, PACC; Robert J. Myerburg, MD,FACC, University of Miami, Miami, Florida.
CRYOSURGICAL ABLATION OF THE AV NODE-HIS BUNDLE: RESULTS AND FOLLOW-UP OF 19 CASES. George J. Klein, MD; Edward L.C. Pritchett, MD; Jackie Kasell; Will C. Scaly, MD; Andrew G. Wallace, MD; John J. Gallagher, MD, Duke University Medical Center, Durham, N. D.
In•a group of 65 consecutive patients(pts)with anomalous atrioventricular (AV) or nodoventricular (NV) bypass tracts, electrophysio!ogical findings suggested the coexistence of dual AV nodal pathways in 8 pts(12.3%).The evidence of coexistent dual AV nodal pathways and anomalous bypass tracts took three forms. In 4 pts, alternating short and long A-H intervals presumably due to rate-dependent 2:1 conduction in the fast AV nodal pathway, were recorded during reciprocating tachycardia(RT). In 3 other pts who had anomalous AV bypass tracts capable of only retrograde conduction, the evidence for coexistent dual AV nodal • pathways Was the observation of discontinuous AI-A2/A2-H2 and AI'A2/HI-H2 curves generated during atrial extrastimulation(AES). In the remaining pt, there was an anomalous NV bypass tract between the slow AV nodal pathway a n d t h e right ventricle. During AES, antegrade block in the fast AV nodal'pathway resulted in antegrade conduction across a pathway composed of the slow AV nodal pathway and the NV bypass tract. This produced right ventricular pr eexcitation with inscription of the His bundle• deflection within the QRS complex. The AI-A2/A2-H2 and AI-A2/HI-H2 curves thus became disrupted. A sustained RT with a complete left bundle branch block pattern was subsequently initiated using the sloW•AV node-NV bypas s tract pathway for antegrade and the fast AV node-His Purkinje system pathway for retrograde conduction.ln summary, these characteristic findings suggest that coexistence of dual AV nodal pathway conduction can be identified electrophysiologically in pts with anomalou§ bypass tracts, and its manifestations may take several forms.
W e have previously described a cryosurgical technique for ablating the AV node-His bundle (AVNH) in patients (pts) with supraventricular tachyarrhythmias unresponsive to medical management. The purpose of this report is to describe the results of 19 such operations. Permanent AV block was achieved in 15 pts (mean follow-up 7.3 months, range 3-34 months). Seven to i0 days post operatively, the pacemaker implanted at the time of surgery was inhibited. A stable cycle length (CL) was achieved within i0 beats (mean • CL = 1213 msec, SD = 191 msec, N = 13). The QRS complex was narrow and identical to the pre-operative morphology in 14 of 15 pts. One pt developed incomplete right bundle branch~'51ock. Atropine (1-2 mg iv) had no significant effect on the escape rhythm (ER) (mean change CL = 36 msec, SD -- 30 msec, N = 6). isoproterenol (1-5 mcg/min) shortened CL of ER in 5/6 pts (mean change CL = 187 msec, SD -- 120 msec). Follow-up of CL of ER (2-30 months) showed no change in 3 pts and increases of 400 and 430 msec in 2 pts respectively. Sudden death occurred in 2 pts known to have had poor ventricular function and ventricular arrhythmias prior to surgery. Failure to ablate AVNH occurred in 4 pts, 2 of whom had large, scarred atria. Complications such as tricuspid insufficiency, ventricular septal defect and sinus of Valsalva aneurysm or fistula, that have been reported with other AVNH ablative techniques, were absent. We conclude that cryosurgical ablation of the AVNH is a safe, effective means of inducing A V block in selected pts with intractable supraventricular tachycardia.
Data in seven patients (aged 33-54 yrs) in whom studies were performed for palpitations or syncope are presented. The QRS duration, axis, and A-H time were normal in all. The H-V time was normal in two (45 msec), and prolonged (55-80 mse¢) in five patients of which two had "split" BH potentials. Extrastimulus technique along with regular atrial•and ventricu!ar stimulation was utilized. In five patients during basic ventricular drive (CL=800-600 msec) and at SIS 2 intervals of 230-335 msec, single ventricular echoes•(VEs) with a narrow QRS complex (~ 95 msec) were seen at V2V 3 intervals of 300-355 msec. V 2 was followed by H 2 (V2H 2 = 250-290 msec) but was not conducted to the atrium. The V3, although narrow, exhibited a shift in axis towards the left • in four and to the right in one patient. The H2V 3 interval was shorter in one patient (40 msec), slightly prolonged (50-65 msec) in two, and similar (65 msec) to the control H-V time in two patients. In the remaining two patients during atrial extrastimulation at SIS 2 intervals of 230 and 320 msec, VEs with narrow QRS complexes were seen at V2V 3 intervals of 300-3i0 msec. V 3 was not preceded by any atrial depolarization, but by a BH deflection at an H-V interval which was shorter (25 and 35 m s e c ) t h a n the control H-V time. In summary, these data show intraventricular reentry with a narrow QRS complex • due to longitudinal dissociation in the His bundle.
February 1979
The American Journal of CARDIOLOGY
Volume 43
389
THE INCIDENCE, DETERMINANTS AND SIGNIFICANCE OF RETROGRADELY FUNCTIONAL ATRIOVENTRICULAR NODAL BYPASS TRACTS ~ A . Gomes, MD, FACC; Malkiat S. Dhatt, MD,•FACC; Anthony N. Dam--~to~ MD~ ~asood Akhtar MD, FACe; Carol Holder, RN, U. S. Public Health Service Hospital, Staten Island, New York The incidence, determinants and significance of retrogradely functional AV nodal bypass tracts (BT) remains unclear. Of i00 patients (pts) with His bundle electrograms and complete anterograde (ant) and retrograde (rat) studies in whom ventricular atrial (VA) BT's were excluded, 18 pts demonstrated electrophysiologic (E) evidence for selective rat utilization of AV nodal BT's characterized by: I) short (36 + 9 msec; mean + SD; range = 25-50 msec) and constant H2 A2 intervals during rat refractory periods (RP) studies which w e r e s i g n i f i c a n t l y ( p < •001) shorter than the AH intervals (78 + 20 msec); 2)significantly (P < .025) better VA than AV conduction (ventricular pacing cycle length with i:i VA = 367 ~ 42 msec;atrial pacing cycle length with I:I AV conduction =•410 ~ 72 msec); 3) significantly (p < .025) shorter rat functional RP of the VA conducting system than the AV conducting system and 4) the rat effective RP of the AV node Was not attained in any of the 18 pts. 14/18 pts (77%) had a history of palpitations and in 13/18 pts (72%) single echoes and/or sustained reentrant supraventricular tachycardia (SVT)could be initiated during E studies. During SVT all 13 pts had short (36 + 9 msec) and constant conduction time in the rat limb(H---Ae intervals) which were identical to the H2 A2 intervals. In conclusion rat AV nodal BT's: i) are functional in 18% of pts and are associated with a high incidence of SVT; 2) provide the substrata in the • initiation and sustenance of reentrant SVT(AV node-His as ant and BT as rat limb) and 3) E findings suggest Hisatrial location Of these BT's.
RE-ENTRY DUE TO LONGITUDINAL DISSOCIATION IN THE HIS BUNDLE (BH) N a r a s i m h a n S h a n t h a ~ M.D., F.A.C.C., Paolo Alboni, M.D., William Towne, M.D., F.A.C.C., Onkar S. Narula, M.D., F.A.C.C.; Cook County Hospital, Chicago, Illinois and The Chicago Medical School, Chicago, Illinois.
ELECTROPHYSIOLOGICAL IDENTIFICATION OF THE COEXISTENCE OF DUAL ATRIOVENTRICULAR NODAL PATHWAY CONDUCTION AND ANOMALOUS BYPASS TRACTS Ruey J. Sung, MD, FACC; Agustin Castellanos,MD, FACC; Stephen M. Mallon, MD, PACC; Robert J. Myerburg, MD,FACC, University of Miami, Miami, Florida.
CRYOSURGICAL ABLATION OF THE AV NODE-HIS BUNDLE: RESULTS AND FOLLOW-UP OF 19 CASES. George J. Klein, MD; Edward L.C. Pritchett, MD; Jackie Kasell; Will C. Scaly, MD; Andrew G. Wallace, MD; John J. Gallagher, MD, Duke University Medical Center, Durham, N. D.
In•a group of 65 consecutive patients(pts)with anomalous atrioventricular (AV) or nodoventricular (NV) bypass tracts, electrophysio!ogical findings suggested the coexistence of dual AV nodal pathways in 8 pts(12.3%).The evidence of coexistent dual AV nodal pathways and anomalous bypass tracts took three forms. In 4 pts, alternating short and long A-H intervals presumably due to rate-dependent 2:1 conduction in the fast AV nodal pathway, were recorded during reciprocating tachycardia(RT). In 3 other pts who had anomalous AV bypass tracts capable of only retrograde conduction, the evidence for coexistent dual AV nodal • pathways Was the observation of discontinuous AI-A2/A2-H2 and AI'A2/HI-H2 curves generated during atrial extrastimulation(AES). In the remaining pt, there was an anomalous NV bypass tract between the slow AV nodal pathway a n d t h e right ventricle. During AES, antegrade block in the fast AV nodal'pathway resulted in antegrade conduction across a pathway composed of the slow AV nodal pathway and the NV bypass tract. This produced right ventricular pr eexcitation with inscription of the His bundle• deflection within the QRS complex. The AI-A2/A2-H2 and AI-A2/HI-H2 curves thus became disrupted. A sustained RT with a complete left bundle branch block pattern was subsequently initiated using the sloW•AV node-NV bypas s tract pathway for antegrade and the fast AV node-His Purkinje system pathway for retrograde conduction.ln summary, these characteristic findings suggest that coexistence of dual AV nodal pathway conduction can be identified electrophysiologically in pts with anomalou§ bypass tracts, and its manifestations may take several forms.
W e have previously described a cryosurgical technique for ablating the AV node-His bundle (AVNH) in patients (pts) with supraventricular tachyarrhythmias unresponsive to medical management. The purpose of this report is to describe the results of 19 such operations. Permanent AV block was achieved in 15 pts (mean follow-up 7.3 months, range 3-34 months). Seven to i0 days post operatively, the pacemaker implanted at the time of surgery was inhibited. A stable cycle length (CL) was achieved within i0 beats (mean • CL = 1213 msec, SD = 191 msec, N = 13). The QRS complex was narrow and identical to the pre-operative morphology in 14 of 15 pts. One pt developed incomplete right bundle branch~'51ock. Atropine (1-2 mg iv) had no significant effect on the escape rhythm (ER) (mean change CL = 36 msec, SD -- 30 msec, N = 6). isoproterenol (1-5 mcg/min) shortened CL of ER in 5/6 pts (mean change CL = 187 msec, SD -- 120 msec). Follow-up of CL of ER (2-30 months) showed no change in 3 pts and increases of 400 and 430 msec in 2 pts respectively. Sudden death occurred in 2 pts known to have had poor ventricular function and ventricular arrhythmias prior to surgery. Failure to ablate AVNH occurred in 4 pts, 2 of whom had large, scarred atria. Complications such as tricuspid insufficiency, ventricular septal defect and sinus of Valsalva aneurysm or fistula, that have been reported with other AVNH ablative techniques, were absent. We conclude that cryosurgical ablation of the AVNH is a safe, effective means of inducing A V block in selected pts with intractable supraventricular tachycardia.
Data in seven patients (aged 33-54 yrs) in whom studies were performed for palpitations or syncope are presented. The QRS duration, axis, and A-H time were normal in all. The H-V time was normal in two (45 msec), and prolonged (55-80 mse¢) in five patients of which two had "split" BH potentials. Extrastimulus technique along with regular atrial•and ventricu!ar stimulation was utilized. In five patients during basic ventricular drive (CL=800-600 msec) and at SIS 2 intervals of 230-335 msec, single ventricular echoes•(VEs) with a narrow QRS complex (~ 95 msec) were seen at V2V 3 intervals of 300-355 msec. V 2 was followed by H 2 (V2H 2 = 250-290 msec) but was not conducted to the atrium. The V3, although narrow, exhibited a shift in axis towards the left • in four and to the right in one patient. The H2V 3 interval was shorter in one patient (40 msec), slightly prolonged (50-65 msec) in two, and similar (65 msec) to the control H-V time in two patients. In the remaining two patients during atrial extrastimulation at SIS 2 intervals of 230 and 320 msec, VEs with narrow QRS complexes were seen at V2V 3 intervals of 300-3i0 msec. V 3 was not preceded by any atrial depolarization, but by a BH deflection at an H-V interval which was shorter (25 and 35 m s e c ) t h a n the control H-V time. In summary, these data show intraventricular reentry with a narrow QRS complex • due to longitudinal dissociation in the His bundle.
February 1979
The American Journal of CARDIOLOGY
Volume 43
389