XML Template (2015) [8.5.2015–2:10pm] //blrnas3.glyph.com/cenpro/ApplicationFiles/Journals/SAGE/3B2/AANJ/Vol00000/150062/APPFile/SG-AANJ150062.3d
(AAN)
[1–7] [PREPRINTER stage]
Original Article
Early postoperative arrhythmias after pediatric cardiac surgery
Asian Cardiovascular & Thoracic Annals 0(0) 1–7 ß The Author(s) 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0218492315585457 aan.sagepub.com
Sachin Talwar, Kartik Patel, Rajnish Juneja, Shiv Kumar Choudhary and Balram Airan
Abstract Background: This prospective study proposed to determine the incidence, risk factors, and management protocols for early postoperative arrhythmias after pediatric cardiac surgery, with focus on outcomes, using a uniform protocol, and also to see if children operated on at a later age have different issues from those operated on earlier. Methods: Of 224 consecutive pediatric patients undergoing cardiac surgery from September 2013 to July 2014, 24 were excluded because their procedures were performed without cardiopulmonary bypass. Results: The median age was 24 months (mean 50.1 62.4 months, range 0.5–216 months). Fifteen (7.5%) patients developed arrhythmia, the most common was junctional ectopic tachycardia (n ¼ 7, 46.6%) followed by supraventricular tachycardia (n ¼ 5, 33.3%). All junctional ectopic tachycardias occurred within 24 h of intensive care unit admission. Of the 7 patients with junctional ectopic tachycardia, 5 responded to conventional measures and 2 required amiodarone infusion. There was a significant longer cardiopulmonary bypass time in patients with arrhythmias compared to those without arrhythmias. Conclusion: We observed a very low incidence of arrhythmias, particularly junctional ectopic tachycardia, after open heart surgery in children. Other than a longer cardiopulmonary bypass time, no specific predictors were identified. It appears that the cause of arrhythmias following pediatric cardiac surgery is multifactorial and needs further study with a greater number of patients.
Keywords Arrhythmias, cardiac, Child, Heart defects, congenital, Postoperative complications, Tachycardia
Introduction Improvements in cardiac surgical techniques have dramatically changed the morbidity and mortality associated with congenital heart disease repairs. Immediate complications are few and mostly manageable. In recent years, much attention has been focused on postoperative arrhythmias which are common in the early postoperative period after cardiac surgery for congenital heart disease.1–3 Although transient and treatable in most cases, they are a cause of substantial morbidity and mortality, especially when they occur in the early vulnerable period of unstable hemodynamics. Despite several studies addressing this issue, vexing issues remain and no comprehensive management guidelines are available. In particular, junctional ectopic tachycardia (JET) remains a notorious arrhythmia that prolongs intensive care unit (ICU) stay and sometimes leads to mortality. Several reports have looked at
the incidence, risk factors, and management of these arrhythmias. However, the wide spectrum of congenital heart diseases and varying surgical approaches to manage them create endless possibilities for the type and outlook of these arrhythmias.4–7 The incidence of acute postoperative arrhythmias ranges from 7.3% to 48%.4–6,8,9 Pathophysiological causes of early postoperative arrhythmias include direct surgical injuries such as myocardial incision, cannulation, sutures close to the conduction system, and acute changes in
Department of Cardiothoracic and Vascular Surgery, All India Institute of Medical Sciences, New Delhi, India Corresponding author: Sachin Talwar, Department of Cardiothoracic and Vascular Surgery, All India Institute of Medical Sciences, New Delhi 110029, India. Email: [email protected]
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XML Template (2015) [8.5.2015–2:10pm] //blrnas3.glyph.com/cenpro/ApplicationFiles/Journals/SAGE/3B2/AANJ/Vol00000/150062/APPFile/SG-AANJ150062.3d
(AAN)
[1–7] [PREPRINTER stage]
2
Asian Cardiovascular & Thoracic Annals 0(0)
intracardiac pressure caused by volume and pressure overload.1–10 Furthermore, cardiopulmonary bypass (CPB) with ischemia-reperfusion and related cellular biochemical effects as well as medical interventions such as electrolyte shifts and catecholamine administration may affect the stability of the cellular membrane and result in increased myocardial irritability and automaticity.11,12 At the All India Institute of Medical Sciences, nearly 50 open heart surgeries are performed every week for congenital heart disorders of all types. Given the vast numbers, this prospective study proposed to determine the incidence, risk factors, and management protocols for early postoperative arrhythmias, with focus on outcomes, using a uniform protocol. Another reason to revisit this problem was to see if children operated on at a later age (not uncommon in our setting) have different issues from those operated at the correct time.
Patients and methods All patients 180 beats min1, and those found to have a heart rate inappropriate for the clinical setting. The ECG of all patients with sustained hemodynamic instability (mean blood pressure 30 s was taken into consideration, as in previous studies that reported a low incidence.8,9 JET was most common arrhythmia, as found in other reported series.2–4 All patients who had JET had a ventricular septal defect either in isolation or with another cardiac malformation. The genesis of JET in this setting could be due to the traction on the tricuspid annulus needed to expose the ventricular septal defect. Nevertheless, we had a low incidence compared to others, which might be explained by the fact that minimal traction was allowed on the tricuspid annulus and stay sutures were used judiciously to gain
intracardiac exposure. Similar results have been reported.2,6 Previous studies have shown an association of JET with surgery for anomalous pulmonary vein drainage or transposition of the great vessels, but we did not observe this.2 Various risk factors for arrhythmia described in the literature include younger age at surgery, prolonged CPB time, longer aortic crossclamp time, cyanosis, deep hypothermic circulatory arrest, and type of surgery.2–4,8,9 In our study, only longer CPB time was associated with a higher incidence of arrhythmia. Similar findings have been reported previously.2–4 Various explanations given for CPB as a causative agent are production of inflammatory markers which alter the myocardial membrane potential, ischemiareperfusion injury, and release of histamine.15,16 Aortic crossclamp time was not found to be significantly associated with arrhythmia, in contrast to previous results.2–4,5 One of the factors for development of arrhythmia is myocardial damage due to ischemiareperfusion injury or free radical-mediated injury.17 Immer and colleagues17 assessed the degree of myocardial damage and the risk of arrhythmia by measuring troponin levels. In our study, serum creatine kinase MB was not significantly higher in patients with arrhythmia, suggesting good myocardial protection. A possible reason could be the use of del Nido cardioplegia,18 which contains mannitol as a free radical scavenger. It has a very high concentration of magnesium, preventing intracellular calcium accumulation. This effect is likely how magnesium improves ventricular recovery in hypothermic cardioplegia solutions when coupled with a low calcium level.18,19 The advantages of del Nido cardioplegia have been described in pediatric as well as adult patients.20 The limitations of this study include the fact that the study population may have been too small to gain any major insight into risk factors because the incidence of all arrhythmias was low; even JET was extremely low, barely 3.5%, which was totally unexpected. The study was not blinded, but this may not have affected the outcomes because the presence or absence of arrhythmias were hard endpoints. Inability to classify some supraventricular tachycardias or labelling them inappropriately as sinus tachycardia was also a limitation because we could not find a cause for these issues. It may have been more useful to do a blinded study comparing two operators or using del Nido cardioplegia vs. other standard cardioplegia solutions, to prove whether it really made a major difference. A doubleblinded study to address the latter issue is already in progress. Although it has been shown that longer CPB times are associated with a higher incidence of JET, it may be interesting to look into why CPB times are longer. Our study did not have adequate numbers,
Downloaded from aan.sagepub.com at Bobst Library, New York University on July 2, 2015
8 4
4 2 2 9 36
JET JET JET JET JET SVT SVT
SVT SVT SVT JET Ventricular bigemini
VSD, pulmonary stenosis
Tetralogy of Fallot
Tetralogy of Fallot
Tetralogy of Fallot
Interrupted aortic arch Anomalous left coronary artery from pulmonary artery Total anomalous pulmonary venous connection Transposition of great vessels þ VSD Transposition of great vessels þ ASD Double-outlet right ventricle þ VSD þ pulmonary stenosis Double-outlet right ventricle þ ASD þ pulmonary stenosis
Downloaded from aan.sagepub.com at Bobst Library, New York University on July 2, 2015
38
86 100 62
50
101 60
48
52
33
64
133 240 117
80
150 138
108
73
57
60
83
100
120
240 170 144
96
312 260
144
120
120
72
72
96
24
50
ICU stay (h)
48
86 87 44
86
59 87
82
52
63
69
85
48
40
CK-MB (U L1)
48
84 72 60
72
72 72
96
48
56
24
28
48
48
Persisted
Duration of arrhythmia (h)
Withdrawal of inotropics Withdrawal of inotropics Withdrawal of inotropics, surface cooling None
Withdrawal of inotropics
Surface cooling, withdrawal inotropics, amiodarone Surface cooling, withdrawal inotropics Surface cooling, withdrawal inotropics, Surface cooling, withdrawal inotropics, Surface cooling, withdrawal inotropics Surface cooling, withdrawal inotropics, amiodarone Withdrawal of inotropics Withdrawal of inotropics
None
Oral beta blocker
Treatment
of
of
of
of
of
of
Recovered
Recovered Recovered Recovered
Recovered
Recovered Recovered
Expired
Recovered
Recovered
Recovered
Recovered
Recovered
Recovered
Continued
Outcome
ASD: atrioventricular septal defect; CK-MB: creatine kinase MB-isoenzyme; ICU: intensive care unit; JET: junctional ectopic tachycardia; SVT: supraventricular tachycardia; VSD: ventricular septal defect.
36
24
24
40
47
73
120
104
CPB time (min)
(AAN)
60
6
9
74
192
VSD, left vena cava
VSD
38
Crossclamp time (min)
204
Ventricular ectopics Sinus bradycardia JET
Age (months)
ASD, pulmonary stenosis, hypertrophic cardiomyopathy Sinus venosus ASD
Diagnosis
Type of arrhythmia
Table 4. Characteristics of the patients who developed arrhythmia.
XML Template (2015) [8.5.2015–2:10pm] //blrnas3.glyph.com/cenpro/ApplicationFiles/Journals/SAGE/3B2/AANJ/Vol00000/150062/APPFile/SG-AANJ150062.3d [1–7] [PREPRINTER stage]
Talwar et al. 5
XML Template (2015) [8.5.2015–2:10pm] //blrnas3.glyph.com/cenpro/ApplicationFiles/Journals/SAGE/3B2/AANJ/Vol00000/150062/APPFile/SG-AANJ150062.3d
(AAN)
[1–7] [PREPRINTER stage]
6
Asian Cardiovascular & Thoracic Annals 0(0)
Table 5. Risk factors for arrhythmias after pediatric cardiac surgery. Variable
Arrhythmia (n ¼ 15)
No Arrhythmia (n ¼ 185)
p value
Age (months) [range] Body surface area (m2) [range] SpO2 [range] Aortic crossclamp time (min) [range] Cardiopulmonary bypass time (min) [range] Temperature during surgery [range] Creatine kinase (U L1) [range] Creatine kinase-MB (U L1) [range] pH [range] HCO3 (mmol L1) [range] Sodium (mEq L1) [range] Potassium (mEq L1) [range] Calcium (mg dL1) [range] Intensive care unit stay (h) [range]
41.9 65.4 0.48 0.38 90.9% 8.5% 62.2 21.42 108.5 46.7 30 C 3.8 C 1327 760.1 65.9 17.3 7.4 0.1 23.1 2.01 141.1 3.3 3.4 0.3 0.9 0.2 134.4 80.5
50.7 62.2 0.59 0.38 94.1% 7.19% 50.6 22.43 79.99 36.5 30.9 C 2.2 C 1138.9 571.8 69.7 15.6 7.4 0.01 23.7 1.6 140.1 3.7 3.3 0.5 1 0.2 59.2 39.7
0.6 0.25 0.10 0.54
(AAN)
[1–7] [PREPRINTER stage]
Original Article
Early postoperative arrhythmias after pediatric cardiac surgery
Asian Cardiovascular & Thoracic Annals 0(0) 1–7 ß The Author(s) 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0218492315585457 aan.sagepub.com
Sachin Talwar, Kartik Patel, Rajnish Juneja, Shiv Kumar Choudhary and Balram Airan
Abstract Background: This prospective study proposed to determine the incidence, risk factors, and management protocols for early postoperative arrhythmias after pediatric cardiac surgery, with focus on outcomes, using a uniform protocol, and also to see if children operated on at a later age have different issues from those operated on earlier. Methods: Of 224 consecutive pediatric patients undergoing cardiac surgery from September 2013 to July 2014, 24 were excluded because their procedures were performed without cardiopulmonary bypass. Results: The median age was 24 months (mean 50.1 62.4 months, range 0.5–216 months). Fifteen (7.5%) patients developed arrhythmia, the most common was junctional ectopic tachycardia (n ¼ 7, 46.6%) followed by supraventricular tachycardia (n ¼ 5, 33.3%). All junctional ectopic tachycardias occurred within 24 h of intensive care unit admission. Of the 7 patients with junctional ectopic tachycardia, 5 responded to conventional measures and 2 required amiodarone infusion. There was a significant longer cardiopulmonary bypass time in patients with arrhythmias compared to those without arrhythmias. Conclusion: We observed a very low incidence of arrhythmias, particularly junctional ectopic tachycardia, after open heart surgery in children. Other than a longer cardiopulmonary bypass time, no specific predictors were identified. It appears that the cause of arrhythmias following pediatric cardiac surgery is multifactorial and needs further study with a greater number of patients.
Keywords Arrhythmias, cardiac, Child, Heart defects, congenital, Postoperative complications, Tachycardia
Introduction Improvements in cardiac surgical techniques have dramatically changed the morbidity and mortality associated with congenital heart disease repairs. Immediate complications are few and mostly manageable. In recent years, much attention has been focused on postoperative arrhythmias which are common in the early postoperative period after cardiac surgery for congenital heart disease.1–3 Although transient and treatable in most cases, they are a cause of substantial morbidity and mortality, especially when they occur in the early vulnerable period of unstable hemodynamics. Despite several studies addressing this issue, vexing issues remain and no comprehensive management guidelines are available. In particular, junctional ectopic tachycardia (JET) remains a notorious arrhythmia that prolongs intensive care unit (ICU) stay and sometimes leads to mortality. Several reports have looked at
the incidence, risk factors, and management of these arrhythmias. However, the wide spectrum of congenital heart diseases and varying surgical approaches to manage them create endless possibilities for the type and outlook of these arrhythmias.4–7 The incidence of acute postoperative arrhythmias ranges from 7.3% to 48%.4–6,8,9 Pathophysiological causes of early postoperative arrhythmias include direct surgical injuries such as myocardial incision, cannulation, sutures close to the conduction system, and acute changes in
Department of Cardiothoracic and Vascular Surgery, All India Institute of Medical Sciences, New Delhi, India Corresponding author: Sachin Talwar, Department of Cardiothoracic and Vascular Surgery, All India Institute of Medical Sciences, New Delhi 110029, India. Email: [email protected]
Downloaded from aan.sagepub.com at Bobst Library, New York University on July 2, 2015
XML Template (2015) [8.5.2015–2:10pm] //blrnas3.glyph.com/cenpro/ApplicationFiles/Journals/SAGE/3B2/AANJ/Vol00000/150062/APPFile/SG-AANJ150062.3d
(AAN)
[1–7] [PREPRINTER stage]
2
Asian Cardiovascular & Thoracic Annals 0(0)
intracardiac pressure caused by volume and pressure overload.1–10 Furthermore, cardiopulmonary bypass (CPB) with ischemia-reperfusion and related cellular biochemical effects as well as medical interventions such as electrolyte shifts and catecholamine administration may affect the stability of the cellular membrane and result in increased myocardial irritability and automaticity.11,12 At the All India Institute of Medical Sciences, nearly 50 open heart surgeries are performed every week for congenital heart disorders of all types. Given the vast numbers, this prospective study proposed to determine the incidence, risk factors, and management protocols for early postoperative arrhythmias, with focus on outcomes, using a uniform protocol. Another reason to revisit this problem was to see if children operated on at a later age (not uncommon in our setting) have different issues from those operated at the correct time.
Patients and methods All patients 180 beats min1, and those found to have a heart rate inappropriate for the clinical setting. The ECG of all patients with sustained hemodynamic instability (mean blood pressure 30 s was taken into consideration, as in previous studies that reported a low incidence.8,9 JET was most common arrhythmia, as found in other reported series.2–4 All patients who had JET had a ventricular septal defect either in isolation or with another cardiac malformation. The genesis of JET in this setting could be due to the traction on the tricuspid annulus needed to expose the ventricular septal defect. Nevertheless, we had a low incidence compared to others, which might be explained by the fact that minimal traction was allowed on the tricuspid annulus and stay sutures were used judiciously to gain
intracardiac exposure. Similar results have been reported.2,6 Previous studies have shown an association of JET with surgery for anomalous pulmonary vein drainage or transposition of the great vessels, but we did not observe this.2 Various risk factors for arrhythmia described in the literature include younger age at surgery, prolonged CPB time, longer aortic crossclamp time, cyanosis, deep hypothermic circulatory arrest, and type of surgery.2–4,8,9 In our study, only longer CPB time was associated with a higher incidence of arrhythmia. Similar findings have been reported previously.2–4 Various explanations given for CPB as a causative agent are production of inflammatory markers which alter the myocardial membrane potential, ischemiareperfusion injury, and release of histamine.15,16 Aortic crossclamp time was not found to be significantly associated with arrhythmia, in contrast to previous results.2–4,5 One of the factors for development of arrhythmia is myocardial damage due to ischemiareperfusion injury or free radical-mediated injury.17 Immer and colleagues17 assessed the degree of myocardial damage and the risk of arrhythmia by measuring troponin levels. In our study, serum creatine kinase MB was not significantly higher in patients with arrhythmia, suggesting good myocardial protection. A possible reason could be the use of del Nido cardioplegia,18 which contains mannitol as a free radical scavenger. It has a very high concentration of magnesium, preventing intracellular calcium accumulation. This effect is likely how magnesium improves ventricular recovery in hypothermic cardioplegia solutions when coupled with a low calcium level.18,19 The advantages of del Nido cardioplegia have been described in pediatric as well as adult patients.20 The limitations of this study include the fact that the study population may have been too small to gain any major insight into risk factors because the incidence of all arrhythmias was low; even JET was extremely low, barely 3.5%, which was totally unexpected. The study was not blinded, but this may not have affected the outcomes because the presence or absence of arrhythmias were hard endpoints. Inability to classify some supraventricular tachycardias or labelling them inappropriately as sinus tachycardia was also a limitation because we could not find a cause for these issues. It may have been more useful to do a blinded study comparing two operators or using del Nido cardioplegia vs. other standard cardioplegia solutions, to prove whether it really made a major difference. A doubleblinded study to address the latter issue is already in progress. Although it has been shown that longer CPB times are associated with a higher incidence of JET, it may be interesting to look into why CPB times are longer. Our study did not have adequate numbers,
Downloaded from aan.sagepub.com at Bobst Library, New York University on July 2, 2015
8 4
4 2 2 9 36
JET JET JET JET JET SVT SVT
SVT SVT SVT JET Ventricular bigemini
VSD, pulmonary stenosis
Tetralogy of Fallot
Tetralogy of Fallot
Tetralogy of Fallot
Interrupted aortic arch Anomalous left coronary artery from pulmonary artery Total anomalous pulmonary venous connection Transposition of great vessels þ VSD Transposition of great vessels þ ASD Double-outlet right ventricle þ VSD þ pulmonary stenosis Double-outlet right ventricle þ ASD þ pulmonary stenosis
Downloaded from aan.sagepub.com at Bobst Library, New York University on July 2, 2015
38
86 100 62
50
101 60
48
52
33
64
133 240 117
80
150 138
108
73
57
60
83
100
120
240 170 144
96
312 260
144
120
120
72
72
96
24
50
ICU stay (h)
48
86 87 44
86
59 87
82
52
63
69
85
48
40
CK-MB (U L1)
48
84 72 60
72
72 72
96
48
56
24
28
48
48
Persisted
Duration of arrhythmia (h)
Withdrawal of inotropics Withdrawal of inotropics Withdrawal of inotropics, surface cooling None
Withdrawal of inotropics
Surface cooling, withdrawal inotropics, amiodarone Surface cooling, withdrawal inotropics Surface cooling, withdrawal inotropics, Surface cooling, withdrawal inotropics, Surface cooling, withdrawal inotropics Surface cooling, withdrawal inotropics, amiodarone Withdrawal of inotropics Withdrawal of inotropics
None
Oral beta blocker
Treatment
of
of
of
of
of
of
Recovered
Recovered Recovered Recovered
Recovered
Recovered Recovered
Expired
Recovered
Recovered
Recovered
Recovered
Recovered
Recovered
Continued
Outcome
ASD: atrioventricular septal defect; CK-MB: creatine kinase MB-isoenzyme; ICU: intensive care unit; JET: junctional ectopic tachycardia; SVT: supraventricular tachycardia; VSD: ventricular septal defect.
36
24
24
40
47
73
120
104
CPB time (min)
(AAN)
60
6
9
74
192
VSD, left vena cava
VSD
38
Crossclamp time (min)
204
Ventricular ectopics Sinus bradycardia JET
Age (months)
ASD, pulmonary stenosis, hypertrophic cardiomyopathy Sinus venosus ASD
Diagnosis
Type of arrhythmia
Table 4. Characteristics of the patients who developed arrhythmia.
XML Template (2015) [8.5.2015–2:10pm] //blrnas3.glyph.com/cenpro/ApplicationFiles/Journals/SAGE/3B2/AANJ/Vol00000/150062/APPFile/SG-AANJ150062.3d [1–7] [PREPRINTER stage]
Talwar et al. 5
XML Template (2015) [8.5.2015–2:10pm] //blrnas3.glyph.com/cenpro/ApplicationFiles/Journals/SAGE/3B2/AANJ/Vol00000/150062/APPFile/SG-AANJ150062.3d
(AAN)
[1–7] [PREPRINTER stage]
6
Asian Cardiovascular & Thoracic Annals 0(0)
Table 5. Risk factors for arrhythmias after pediatric cardiac surgery. Variable
Arrhythmia (n ¼ 15)
No Arrhythmia (n ¼ 185)
p value
Age (months) [range] Body surface area (m2) [range] SpO2 [range] Aortic crossclamp time (min) [range] Cardiopulmonary bypass time (min) [range] Temperature during surgery [range] Creatine kinase (U L1) [range] Creatine kinase-MB (U L1) [range] pH [range] HCO3 (mmol L1) [range] Sodium (mEq L1) [range] Potassium (mEq L1) [range] Calcium (mg dL1) [range] Intensive care unit stay (h) [range]
41.9 65.4 0.48 0.38 90.9% 8.5% 62.2 21.42 108.5 46.7 30 C 3.8 C 1327 760.1 65.9 17.3 7.4 0.1 23.1 2.01 141.1 3.3 3.4 0.3 0.9 0.2 134.4 80.5
50.7 62.2 0.59 0.38 94.1% 7.19% 50.6 22.43 79.99 36.5 30.9 C 2.2 C 1138.9 571.8 69.7 15.6 7.4 0.01 23.7 1.6 140.1 3.7 3.3 0.5 1 0.2 59.2 39.7
0.6 0.25 0.10 0.54
