Neonatal arrhythmias
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《美国医学杂志》
Department of Pediatrics, Government Medical College and Hospital, Chandigarh, India
Abstract
Objective : Neonatal arrhythmias are not uncommon; however, they rarely cause hemodynamic compromise. This paper aims to study the etiology, spectrum and outcome of neonates with arrhythmias who presented to a pediatric department. Methods : All neonates, either inborn or brought to the pediatric emergency with rhythm disorders, between August 1999 to August 2002, were included prospectively. Evaluation including a search for secondary causes of rhythm disorder and a chest X-ray, standard 12-lead electrocardiography and echocardiography in all. The management required in each and the outcomes were noted. Results : Nine neonates were identified, of which 4 were inborn. Tachycardia was seen in 8 neonates, and bradycardia in only one. Three neonates had an antenatal onset of arrhythmias; in the rest it was postnatal in onset. Five neonates had a secondary rhythm disorder, secondary to metabolic derangements in 4 and a cardiac mass in 1. Five had ventricular arrhythmias, and 5 had hemodynamic compromise due to the arrhythmia. The outcome was poor in 4 and was related to the underlying illness. Conclusion : Tachyarrhythmia is more common than bradyarrhythmia in the neonate. Arrhythmias secondary to various metabolic causes are more common than primary rhythm disorders.
Keywords: Neonatal Arrhythmias; Tachycardia; Ventricular; Diseases; Metabolic; Hyperkalemia
Symptomatic neonatal arrhythmias are rare[1]; supraventricular tachycardia (SVT) being the commonest among them. Ventricular arrhythmias are often secondary to metabolic disturbances and are hence potentially easily treatable.[1] This report presents the neonates with arrhythmias, who presented to a pediatric department, over a 3-year period.
Between August 1999 to August 2002, 9 neonates with dysrhythmias were identified; 4 of them were inborn, while the rest presented to the emergency. A complete septic work-up, serum electrolytes, renal function tests, blood sugar, arterial blood gas analysis were done in the symptomatic babies; and chest x-ray, a standard 12-lead electrocardiogram and echocardiography were done in all. The details of the patients are as in table1.
Four babies had a primary rhythm disorder, and in the rest it was secondary. Three babies had benign atrial ventricular ectopics detected antenatally, which disappeared in early infancy. One neonate had congenital complete heart block (no. 4) and showed no increment in heart rate with drugs and remained in shock. Following temporary cardiac pacing, the heart rate normalized but the child died due to the effects of prolonged hypoxia.
The secondary arrhythmias were ventricular in origin in four out of five babies. The arrhythmias were secondary to metabolic disturbances in 4, septicemia with meningitis in one and left atrial mass lesion in another.
One neonate (no. 5) had a pedunculated mass arising from the inter - atrial septum and projecting into the left atrium leading to recurrent episodes of SVT. She required intravenous adenosine twice to revert the rhythm to normal and was subsequently started on digoxin. The pathology of this mass lesion could not be confirmed as the parents refused to take the child to a higher center for further management.
One neonate with septicemia and meningitis (no. 6) had two episodes of pulseless ventricular tachycardia requiring defibrillation and was started on a lidocaine infusion subsequently. He succumbed to his underlying illness within 24 hours of admission.
Severe acidosis (mixed), along with hypoxia, led to runs of ventricular ectopics in a sick, low birth-weight neonate (no. 7); however, there was no evidence of hemodynamic compromise. Hyperkalemia and metabolic acidosis induced transient ventricular tachyarrhythmias in two neonates, in addition to hypocalcemia in one (no. 8) and renal failure in the other (no. 9). These neonates required no active intervention for ventricular arrhythmias and the rhythm reverted to normal with correction of the underlying metabolic abnormalities.
Discussion
Cardiac arrhythmias have been reported in up to 1% of apparently normal newborns.[1] However, a majority of them are clinically asymptomatic, while life-threatening arrhythmias occur rarely.
Ventricular and supraventricular ectopics are benign and self-limited. On routine screening before discharge, ectopics have been reported to occur in about 1% of neonates. These arrhythmias may be seen with metabolic abnormalities and hypoxia but are also seen in otherwise normal newborns.[2] The prognosis is excellent, with ectopy disappearing within the first month of life.[1],[2],[3] Three neonates had benign ectopics, which disappeared in early infancy. One sick neonate with ectopics secondary to acidosis and hypoxia (no. 7), with disappearance of ectopics after correction of metabolic abnormalities, succumbed to his primary illness. Awareness regarding the harmless nature of these ectopics is necessary to avoid needless intervention.
Congenital complete heart block is relatively common, occurring in 1 in 15,000 to 20,000 live births.[1],[4] Its association with certain structural congenital heart lesions or maternal systemic lupus erythematosus (SLE) is well known.[5] Symptoms develop due to congestive heart failure and low cardiac output in babies with low heart rates[2],[4], as in the case described. Indications for emergency pacing in asymptomatic babies include ventricular rates < 55 bpm, wide complex escape rhythm, cardiomegaly etc; however, all symptomatic babies should receive a pacemaker.[2],[4]
SVT is the commonest tachyarrhythmia among the neonates[2]; however, we found only one such case (no.5). This neonate was found to have recurrent AV reciprocating re-entry tachycardia causing hemodynamic compromise due to a possible cardiac tumour. Cardiac tumors are very rare in the pediatric population and more so in infants.[1],[6] Rhabdomyomas are the commonest cardiac tumors in neonates (up to 50% of primary cardiac tumors).[1],[6],[7] However, the mass in the case reported here was pedunculated, arising from the inter-atrial septum and projecting into the left atrium and is hence unlikely to be a rhabdomyoma. This is likely to be a myxoma due to its pedunculated nature and location. Though rare (10 to 15% of primary cardiac tumors in children), myxomas can occur even in neonates, often mimicking congenital heart disease. Arrhythmias arising due to cardiac tumors are well known, as they can be located in the region of the conduction system of the heart.[6] Medical management was ineffective in this patient; surgical intervention would have been curative.
Ventricular tachyarrhythmias are rare events in neonates[1],[2],[7], and are often secondary. Hyperkalemia and metabolic acidosis, in addition to hypocalcemia in one and renal failure in the other, resulted in ventricular tachyarrhythmias in two neonates (no.8, 9). Correction of metabolic abnormalities that caused the rhythm disturbances led to reversion to normal rhythm in both the cases. However, the ultimate outcome was determined by the underlying illness that led to the metabolic abnormalities.
Septicemia with meningitis led to recurrent ventricular tachycardia in one neonate (no.6). There were no obvious electrolyte imbalances, or hypoglycemia. Hypoxia and ischemia due to septicemia and the resultant shock could have contributed to ventricular tachycardia. An adverse outcome was noted in this baby, again reflecting the seriousness of the underlying illness.
Ventricular tachyarrhythmias in the neonate are not only rare, but also poorly understood.[7] Idiopathic ventricular tachycardia in neonates has been described, which has a favourable outcome.[7] Various reports of ventricular tachyarrhythmias secondary to metabolic abnormalities including hyperkalemia,[8],[9] hypoglycemia[10] and hypoxia are available. The current case-series highlights the same and it is hence of utmost importance to correct these metabolic abnormalities before using conventional anti-arrhythmic therapy.[8]
In conclusion, awareness about the various arrhythmias that can present in the neonatal period is necessary. A careful search for precipitating factors such as metabolic abnormalities, if any, should be undertaken promptly and unnecessary anti-arrhythmic medication and investigations may be avoided.
References
1. Long WA, Frantz EG, Henry GW, Freed MD and Brook M. Evaluation of newborns with possible cardiac problems. In Taeusch HW, Ballard RA, eds. Avery's diseases of the newborn. 7th edn. Noida; Harcourt Asia Pte Ltd., 2000, 711-763.
2. Tanel RE, Rhodes LA. Fetal and neonatal arrhythmias. Clin Perinatology 2001; 28(1): 187-207.
3. Goraya JS, Basu S, Parmar VR. Fetal and neonatal extrasystoles. Indian Pediatr 2000; 37(7): 784-786.
4. Pinsky WW, Gillette PC, Garson AT, Mc Namara DG. Diagnosis, management and long-term results of patients with complete atrioventricular block. Pediatrics 1982; 69: 728-733.
5. Litsey SE et al. Maternal connective tissue disease and congenital heart block: demonstration of immunoglobulin in cardiac tissue. N Engl J Med 1985; 312 : 98-100.
6. Ludomirsky A. Cardiac tumours. In Garson A, Bricker JT, Fisher DJ, Neish SR, eds. The science and practice of pediatric cardiology. 2nd edn. Baltimore; Williams and Wilkins, 1998; 1885-1893.
7. Villain E, Butera G, Bonnet D, Acar P, Aggoun Y, Kachaner J. [Neonatal ventricular tachycardia] (article in French). Arch Mal Couer Vaiss 1998; 91(5): 623-9
8. Virdi VS, Bharti B, Poddar B, Basu S, Parmar VR. Ventricular tachycardia in congenital adrenal hyperplasia. Anaesth Intensive Care 2002; 30: 380-381.
9. Singh D, Dutta S, Narang A. Hyperkalemia and ventricular tachycardia in ELBW infant. Indian Pediatr 2003; 40(1): 64-66.
10. Chelliah YR. Ventricular tachycardia associated with hypoglycemia. Anaesth Intensive Care 2000; 28: 698-700.(Poddar Banani, Basu Srika)
Abstract
Objective : Neonatal arrhythmias are not uncommon; however, they rarely cause hemodynamic compromise. This paper aims to study the etiology, spectrum and outcome of neonates with arrhythmias who presented to a pediatric department. Methods : All neonates, either inborn or brought to the pediatric emergency with rhythm disorders, between August 1999 to August 2002, were included prospectively. Evaluation including a search for secondary causes of rhythm disorder and a chest X-ray, standard 12-lead electrocardiography and echocardiography in all. The management required in each and the outcomes were noted. Results : Nine neonates were identified, of which 4 were inborn. Tachycardia was seen in 8 neonates, and bradycardia in only one. Three neonates had an antenatal onset of arrhythmias; in the rest it was postnatal in onset. Five neonates had a secondary rhythm disorder, secondary to metabolic derangements in 4 and a cardiac mass in 1. Five had ventricular arrhythmias, and 5 had hemodynamic compromise due to the arrhythmia. The outcome was poor in 4 and was related to the underlying illness. Conclusion : Tachyarrhythmia is more common than bradyarrhythmia in the neonate. Arrhythmias secondary to various metabolic causes are more common than primary rhythm disorders.
Keywords: Neonatal Arrhythmias; Tachycardia; Ventricular; Diseases; Metabolic; Hyperkalemia
Symptomatic neonatal arrhythmias are rare[1]; supraventricular tachycardia (SVT) being the commonest among them. Ventricular arrhythmias are often secondary to metabolic disturbances and are hence potentially easily treatable.[1] This report presents the neonates with arrhythmias, who presented to a pediatric department, over a 3-year period.
Between August 1999 to August 2002, 9 neonates with dysrhythmias were identified; 4 of them were inborn, while the rest presented to the emergency. A complete septic work-up, serum electrolytes, renal function tests, blood sugar, arterial blood gas analysis were done in the symptomatic babies; and chest x-ray, a standard 12-lead electrocardiogram and echocardiography were done in all. The details of the patients are as in table1.
Four babies had a primary rhythm disorder, and in the rest it was secondary. Three babies had benign atrial ventricular ectopics detected antenatally, which disappeared in early infancy. One neonate had congenital complete heart block (no. 4) and showed no increment in heart rate with drugs and remained in shock. Following temporary cardiac pacing, the heart rate normalized but the child died due to the effects of prolonged hypoxia.
The secondary arrhythmias were ventricular in origin in four out of five babies. The arrhythmias were secondary to metabolic disturbances in 4, septicemia with meningitis in one and left atrial mass lesion in another.
One neonate (no. 5) had a pedunculated mass arising from the inter - atrial septum and projecting into the left atrium leading to recurrent episodes of SVT. She required intravenous adenosine twice to revert the rhythm to normal and was subsequently started on digoxin. The pathology of this mass lesion could not be confirmed as the parents refused to take the child to a higher center for further management.
One neonate with septicemia and meningitis (no. 6) had two episodes of pulseless ventricular tachycardia requiring defibrillation and was started on a lidocaine infusion subsequently. He succumbed to his underlying illness within 24 hours of admission.
Severe acidosis (mixed), along with hypoxia, led to runs of ventricular ectopics in a sick, low birth-weight neonate (no. 7); however, there was no evidence of hemodynamic compromise. Hyperkalemia and metabolic acidosis induced transient ventricular tachyarrhythmias in two neonates, in addition to hypocalcemia in one (no. 8) and renal failure in the other (no. 9). These neonates required no active intervention for ventricular arrhythmias and the rhythm reverted to normal with correction of the underlying metabolic abnormalities.
Discussion
Cardiac arrhythmias have been reported in up to 1% of apparently normal newborns.[1] However, a majority of them are clinically asymptomatic, while life-threatening arrhythmias occur rarely.
Ventricular and supraventricular ectopics are benign and self-limited. On routine screening before discharge, ectopics have been reported to occur in about 1% of neonates. These arrhythmias may be seen with metabolic abnormalities and hypoxia but are also seen in otherwise normal newborns.[2] The prognosis is excellent, with ectopy disappearing within the first month of life.[1],[2],[3] Three neonates had benign ectopics, which disappeared in early infancy. One sick neonate with ectopics secondary to acidosis and hypoxia (no. 7), with disappearance of ectopics after correction of metabolic abnormalities, succumbed to his primary illness. Awareness regarding the harmless nature of these ectopics is necessary to avoid needless intervention.
Congenital complete heart block is relatively common, occurring in 1 in 15,000 to 20,000 live births.[1],[4] Its association with certain structural congenital heart lesions or maternal systemic lupus erythematosus (SLE) is well known.[5] Symptoms develop due to congestive heart failure and low cardiac output in babies with low heart rates[2],[4], as in the case described. Indications for emergency pacing in asymptomatic babies include ventricular rates < 55 bpm, wide complex escape rhythm, cardiomegaly etc; however, all symptomatic babies should receive a pacemaker.[2],[4]
SVT is the commonest tachyarrhythmia among the neonates[2]; however, we found only one such case (no.5). This neonate was found to have recurrent AV reciprocating re-entry tachycardia causing hemodynamic compromise due to a possible cardiac tumour. Cardiac tumors are very rare in the pediatric population and more so in infants.[1],[6] Rhabdomyomas are the commonest cardiac tumors in neonates (up to 50% of primary cardiac tumors).[1],[6],[7] However, the mass in the case reported here was pedunculated, arising from the inter-atrial septum and projecting into the left atrium and is hence unlikely to be a rhabdomyoma. This is likely to be a myxoma due to its pedunculated nature and location. Though rare (10 to 15% of primary cardiac tumors in children), myxomas can occur even in neonates, often mimicking congenital heart disease. Arrhythmias arising due to cardiac tumors are well known, as they can be located in the region of the conduction system of the heart.[6] Medical management was ineffective in this patient; surgical intervention would have been curative.
Ventricular tachyarrhythmias are rare events in neonates[1],[2],[7], and are often secondary. Hyperkalemia and metabolic acidosis, in addition to hypocalcemia in one and renal failure in the other, resulted in ventricular tachyarrhythmias in two neonates (no.8, 9). Correction of metabolic abnormalities that caused the rhythm disturbances led to reversion to normal rhythm in both the cases. However, the ultimate outcome was determined by the underlying illness that led to the metabolic abnormalities.
Septicemia with meningitis led to recurrent ventricular tachycardia in one neonate (no.6). There were no obvious electrolyte imbalances, or hypoglycemia. Hypoxia and ischemia due to septicemia and the resultant shock could have contributed to ventricular tachycardia. An adverse outcome was noted in this baby, again reflecting the seriousness of the underlying illness.
Ventricular tachyarrhythmias in the neonate are not only rare, but also poorly understood.[7] Idiopathic ventricular tachycardia in neonates has been described, which has a favourable outcome.[7] Various reports of ventricular tachyarrhythmias secondary to metabolic abnormalities including hyperkalemia,[8],[9] hypoglycemia[10] and hypoxia are available. The current case-series highlights the same and it is hence of utmost importance to correct these metabolic abnormalities before using conventional anti-arrhythmic therapy.[8]
In conclusion, awareness about the various arrhythmias that can present in the neonatal period is necessary. A careful search for precipitating factors such as metabolic abnormalities, if any, should be undertaken promptly and unnecessary anti-arrhythmic medication and investigations may be avoided.
References
1. Long WA, Frantz EG, Henry GW, Freed MD and Brook M. Evaluation of newborns with possible cardiac problems. In Taeusch HW, Ballard RA, eds. Avery's diseases of the newborn. 7th edn. Noida; Harcourt Asia Pte Ltd., 2000, 711-763.
2. Tanel RE, Rhodes LA. Fetal and neonatal arrhythmias. Clin Perinatology 2001; 28(1): 187-207.
3. Goraya JS, Basu S, Parmar VR. Fetal and neonatal extrasystoles. Indian Pediatr 2000; 37(7): 784-786.
4. Pinsky WW, Gillette PC, Garson AT, Mc Namara DG. Diagnosis, management and long-term results of patients with complete atrioventricular block. Pediatrics 1982; 69: 728-733.
5. Litsey SE et al. Maternal connective tissue disease and congenital heart block: demonstration of immunoglobulin in cardiac tissue. N Engl J Med 1985; 312 : 98-100.
6. Ludomirsky A. Cardiac tumours. In Garson A, Bricker JT, Fisher DJ, Neish SR, eds. The science and practice of pediatric cardiology. 2nd edn. Baltimore; Williams and Wilkins, 1998; 1885-1893.
7. Villain E, Butera G, Bonnet D, Acar P, Aggoun Y, Kachaner J. [Neonatal ventricular tachycardia] (article in French). Arch Mal Couer Vaiss 1998; 91(5): 623-9
8. Virdi VS, Bharti B, Poddar B, Basu S, Parmar VR. Ventricular tachycardia in congenital adrenal hyperplasia. Anaesth Intensive Care 2002; 30: 380-381.
9. Singh D, Dutta S, Narang A. Hyperkalemia and ventricular tachycardia in ELBW infant. Indian Pediatr 2003; 40(1): 64-66.
10. Chelliah YR. Ventricular tachycardia associated with hypoglycemia. Anaesth Intensive Care 2000; 28: 698-700.(Poddar Banani, Basu Srika)