Patterns children
of atrioventricular
Devkishin B. Pahlajani, Robert A. Miller, M.D. Maria Serratto, M.D. Chicago,
conduction
M.D.
Ill.
Introduction of His bundle electrography in clinical cardiology has helped to clarify the mechanisms of arrhythmias and conduction defects in the human heart. This technique has been used to determine the atrioventricular (AV) conduction times,’ the response to atria1 pacing,2 and to study conduction patterns by extrastimulus technique.3 Data on refractory periods are lacking in children; however, since the submittal of this manuscript, a paper on this subject has been published.3a The heart rates of children are faster than those of the adult and their conduction system is relatively free from atherosclerotic and degenerative heart disease. Therefore, it is reasonable to expect that the conduction system data will be different from those of the adults. We have studied the response of the A-V conduction system to atria1 pacing and atria1 premature depolarization (APD) in children with normal conduction. Material
and methods
Studies were performed on 20 children with no evidence of conduction disturbance on routine scalar electrocardiogram (ECG) being catheterized for congenital or acquired heart disease. Their ages ranged from eight months to 18 years. Their clinical and ECG diagnosis are listed in Table I. All recordings were performed in the postabsorbtive state under Demerol, 1 mg. per pound, Phenergan, 0.5 mg. per pound, and SparFrom the Division of Pediatric Cardiology, Cook Hospital, and the Hektoen Institute for Medical Ill. Supported
in part
Received
for publication
by
the July
Children’s
Heart
County Research,
Research
Children’s Chicago, Foundation.
19, 1974.
Reprint requests: Dr. Maria Serratto, Division 700 S. Wood St., Cook County Children’s 60612.
August,
in
of Pediatric Hospital,
1975, Vol. 90, No. 2, pp. 165-171
Cardiology, Chicago, Ill.
ine, 0.5 mg. per pound sedation. None were on cardioactive drugs at the time of study. Recording technique. His Bundle electrograms (HBE) were recorded by placing an appropriate size tripolar catheter close to the tricuspid valve.’ A quadripolar catheter was placed in the right atrium and its distal two poles were utilized for recording high right atria1 electrogram and the proximal two poles for atria1 pacing. Simultaneous ECG Leads I, II, and III were recorded. Both catheters were introduced via femoral veins by percutaneous introduction technique. All recordings were made on Electronics for Medicine DR16 multichannel recorder at paper speeds of 100 and 200 mm. per second. Stimuli were delivered to the right atrium by a Grass stimulator Model DS88. Atria1 pacing was performed to the maximum of 300 beats per minute and/or until Wenckebach block developed. Refractory periods were measured by the extrastimulus technique. ! The right atrium was driven at the slowest possible rate that insured reliable atria1 capture by the basic driving stimulus (S,). A test stimulus (S,) was introduced after every tenth beat. SZ was delivered in late diastole and moved progressively earlier by 10 to 20 msec. decrements in successive test cycles. The AH and HV intervals were measured as previously described.” A,~ H,~ and V, represent the atrial, His Bundle (H), and ventricular electrograms of the basically driven beats. A? H,, and V, represent the atrial, H, and ventricular electrograms in response to S,. Definitions. The A-V nodal effective refractory period (ERP) is the longest A,A, interval which does not propagate to H. A-V nodal functional refractory period (FRP) is the shortest interval between two successive H responses both propa-
American
Heart
Journal
165
Pahlajani,
Miller,
and
Table I. Clinical,
Case No.
electrocardiographic
and electrophysiologic Intervals (msec.) I I PA AH HV
Diagnosis
ECG Dx LVH IRBBB CVH N
150 145
8 28
112 70
17 25
122
18
105
26
IRBBB
130
10
95
30
IRBBB
140
15
72
N
loo130 110
20
LVH RVH N LVH
12.
M 8 mos. PDA F 11 VSD+ mos. DRV Ml1 NH mos. M 18 VSD mos. M 19 VSD mos. M24 Coarc mos. PA F 26 ASDmos. PO PDA F 3 yrs. PDA M 4 yrs. DORV F 6yrs. PDA F 7yrs. PO PDA M 9 yrs. ASD
13. 14.
MlOyrs.NH F 13yrs.TA
15.
M 13yrs.A+
IRBBB RAE N LVH LAD LVH
1. 2. 3. 4. 5. 6. 7.
8. 9. 10. 11.
16. 17. 18. 19. 20.
Sex and age
Serratto
IRBBB LAD
MR M 13~1s. PO IRBBB VSD M 14yrs. AS+RLVH Bord. M 15yrs.AR LVH M 15yrs.TA LVH LAD F 18 yrs. VSD LAE
PDA - Patent ductus artmioms. VSD - Ventricular-aeptal defect. DRV - Divided right ventricle. NH - Normal heart. Coarc PA - Coarctation of pulmonary ASD - Atrial-aeptal defect. PO - Postoperative. DORV - Double-outlet right ventricle. TA - Txicuspid atreaia. A - Aortic. M - Mitral. R - Regurgitation.
HR
Refractory periods Response to atria1 pacing Atrium A-V node Pacing I I I Type Rate Rate FRP ERP FRP ERP Wenck. Wenck.
BB
HPS
RP
RRP
280 280
160 170
130 140
120 130
-
-
260
140
150
140
285
160
-
Wenck.
240
145
160
150
278
200
-
30
Wenck.
280
165
180
170-
-
-
71
34
Wenck.
200
140
210
200-
-
15
100
30
Wenck.
180
115
210
200-
-
145 140 117 115
15 10 18 15
95 111 85 120
29 30 32 24
1:l Wenck. 1:l
240 240 240
175 150 130 125
140 200 170 t170
130180 150
of atrioventricular
Devkishin B. Pahlajani, Robert A. Miller, M.D. Maria Serratto, M.D. Chicago,
conduction
M.D.
Ill.
Introduction of His bundle electrography in clinical cardiology has helped to clarify the mechanisms of arrhythmias and conduction defects in the human heart. This technique has been used to determine the atrioventricular (AV) conduction times,’ the response to atria1 pacing,2 and to study conduction patterns by extrastimulus technique.3 Data on refractory periods are lacking in children; however, since the submittal of this manuscript, a paper on this subject has been published.3a The heart rates of children are faster than those of the adult and their conduction system is relatively free from atherosclerotic and degenerative heart disease. Therefore, it is reasonable to expect that the conduction system data will be different from those of the adults. We have studied the response of the A-V conduction system to atria1 pacing and atria1 premature depolarization (APD) in children with normal conduction. Material
and methods
Studies were performed on 20 children with no evidence of conduction disturbance on routine scalar electrocardiogram (ECG) being catheterized for congenital or acquired heart disease. Their ages ranged from eight months to 18 years. Their clinical and ECG diagnosis are listed in Table I. All recordings were performed in the postabsorbtive state under Demerol, 1 mg. per pound, Phenergan, 0.5 mg. per pound, and SparFrom the Division of Pediatric Cardiology, Cook Hospital, and the Hektoen Institute for Medical Ill. Supported
in part
Received
for publication
by
the July
Children’s
Heart
County Research,
Research
Children’s Chicago, Foundation.
19, 1974.
Reprint requests: Dr. Maria Serratto, Division 700 S. Wood St., Cook County Children’s 60612.
August,
in
of Pediatric Hospital,
1975, Vol. 90, No. 2, pp. 165-171
Cardiology, Chicago, Ill.
ine, 0.5 mg. per pound sedation. None were on cardioactive drugs at the time of study. Recording technique. His Bundle electrograms (HBE) were recorded by placing an appropriate size tripolar catheter close to the tricuspid valve.’ A quadripolar catheter was placed in the right atrium and its distal two poles were utilized for recording high right atria1 electrogram and the proximal two poles for atria1 pacing. Simultaneous ECG Leads I, II, and III were recorded. Both catheters were introduced via femoral veins by percutaneous introduction technique. All recordings were made on Electronics for Medicine DR16 multichannel recorder at paper speeds of 100 and 200 mm. per second. Stimuli were delivered to the right atrium by a Grass stimulator Model DS88. Atria1 pacing was performed to the maximum of 300 beats per minute and/or until Wenckebach block developed. Refractory periods were measured by the extrastimulus technique. ! The right atrium was driven at the slowest possible rate that insured reliable atria1 capture by the basic driving stimulus (S,). A test stimulus (S,) was introduced after every tenth beat. SZ was delivered in late diastole and moved progressively earlier by 10 to 20 msec. decrements in successive test cycles. The AH and HV intervals were measured as previously described.” A,~ H,~ and V, represent the atrial, His Bundle (H), and ventricular electrograms of the basically driven beats. A? H,, and V, represent the atrial, H, and ventricular electrograms in response to S,. Definitions. The A-V nodal effective refractory period (ERP) is the longest A,A, interval which does not propagate to H. A-V nodal functional refractory period (FRP) is the shortest interval between two successive H responses both propa-
American
Heart
Journal
165
Pahlajani,
Miller,
and
Table I. Clinical,
Case No.
electrocardiographic
and electrophysiologic Intervals (msec.) I I PA AH HV
Diagnosis
ECG Dx LVH IRBBB CVH N
150 145
8 28
112 70
17 25
122
18
105
26
IRBBB
130
10
95
30
IRBBB
140
15
72
N
loo130 110
20
LVH RVH N LVH
12.
M 8 mos. PDA F 11 VSD+ mos. DRV Ml1 NH mos. M 18 VSD mos. M 19 VSD mos. M24 Coarc mos. PA F 26 ASDmos. PO PDA F 3 yrs. PDA M 4 yrs. DORV F 6yrs. PDA F 7yrs. PO PDA M 9 yrs. ASD
13. 14.
MlOyrs.NH F 13yrs.TA
15.
M 13yrs.A+
IRBBB RAE N LVH LAD LVH
1. 2. 3. 4. 5. 6. 7.
8. 9. 10. 11.
16. 17. 18. 19. 20.
Sex and age
Serratto
IRBBB LAD
MR M 13~1s. PO IRBBB VSD M 14yrs. AS+RLVH Bord. M 15yrs.AR LVH M 15yrs.TA LVH LAD F 18 yrs. VSD LAE
PDA - Patent ductus artmioms. VSD - Ventricular-aeptal defect. DRV - Divided right ventricle. NH - Normal heart. Coarc PA - Coarctation of pulmonary ASD - Atrial-aeptal defect. PO - Postoperative. DORV - Double-outlet right ventricle. TA - Txicuspid atreaia. A - Aortic. M - Mitral. R - Regurgitation.
HR
Refractory periods Response to atria1 pacing Atrium A-V node Pacing I I I Type Rate Rate FRP ERP FRP ERP Wenck. Wenck.
BB
HPS
RP
RRP
280 280
160 170
130 140
120 130
-
-
260
140
150
140
285
160
-
Wenck.
240
145
160
150
278
200
-
30
Wenck.
280
165
180
170-
-
-
71
34
Wenck.
200
140
210
200-
-
15
100
30
Wenck.
180
115
210
200-
-
145 140 117 115
15 10 18 15
95 111 85 120
29 30 32 24
1:l Wenck. 1:l
240 240 240
175 150 130 125
140 200 170 t170
130180 150
