Successful management of refractory supraventricular tachycardia in a 4-month-old infant

Suba. P¹, S. J. Soniya Mercy Anbu², Ruby Ravichandran³

¹ER Staff Nurse, Maa Kauvery, Trichy, Tamil Nadu

²Assistant Nursing Superintend, Maa Kauvery, Trichy, Tamil Nadu

³Deputy Nursing Superintend, Maa Kauvery, Trichy, Tamil Nadu

Introduction

Supraventricular tachycardia (SVT) is a common cardiac arrythmia characterized by abnormally rapid heart rate originating above the ventricles, typically involving the atria or artrioventricular AV node. It often presents with sudden onset and termination of palpitations, dizziness, chest discomfort, dyspnea, or syncope, and may occur in individuals with or without underlying structural heart disease. SVT is frequently encountered in emergency and critical care settings and requires prompt recognition and management to prevent hemodynamic instability and associated complications. Although generally considered benign, recurrent or prolonged episodes can significantly impact quality of life and may lead to adverse outcomes, if left untreated. This is a case of SVT to highlight its clinical presentation, diagnostic evaluation, acute management, and outcome, emphasizing the importance of early intervention and appropriate drug therapy

4 months old male child was brought with the complaints of coryza and cough for 2 weeks, intermittent and non productive cough, He was initially treated as an outpatient with oral medications and nebulization. Coryza settled but intermittent dry cough persistant and child became irritable with poor oral intake and fast breathing for a day. Child was treated in a hospital prior to admission and was noted to have extreme tachycardia, hence referred for further management.

There was no history of vomiting / loose stools / abdominal distension / recent travel / seizures / altered sensorium

Past history: Nil significant

Antenatal & Birth history: Term / Birth weight: 3.8kg / LSCS / no NICU stay

Development history: Appropriate for age

Language: Cooing and babbling present

Social: Smiles at mother

Immunization history: Immunized till date in according to NIS

Clinical Findings: Child was irritable but consolable

Pulse volume: Good

Vitals signs

Temp	98 F
HR	280/mt
RR	50/mt
SPO2	98 %
BP	90/60 mmHg.

Anthropometry	Measurement	Centile
Weight	6.7kg	0 to 2SD
Height	67cm	0 to 2SD
Weight for HT / LT	-	-2 to -3SD
Head circumference	43cm	1 to 2SD
Inference: Normal

Systemic Examination

CVS	Heart sounds were normal:there was no murmur , Tachycardia present
RS	There were subcostal retractions and scattered crepitation.
P/A	Liver palpable 3cm below right costal margin, No splenomegaly
CNS	Irritable but consolable , E4 VC M6, Bilateral pupils 2mm equally to light, Tone :Normal in all four limbs, Power : >3/5 in all four limbs

Supra ventricular tachycardia

Sinus tachycardia

Mangement

On arrival, the child was in extreme tachycardia (>250/mt) with minimal subcostal retractions and bilateral minimal crepitation’s, mild hepatomegaly, and irritable cry but was consolable. 12 lead ECG showed, supra ventricular tachycardia with good peripheral pulse, but was highly irritable hence 2 doses of Adenosine trial were given but not reverted. On defibrillator monitor, was suggestive of the rhythm supra ventricular tachycardia with wide QRS complex. Peripheral pulses became feeble. Synchronized cardioversion was attempted under sedation initially with 0.5J/kg followed by 2J/kg. There was no response. The child continued to be irritable, peripheral pulses were feeble, and there was ventricular tachycardia on defibrillator hence 3J/kg was given transiently reverted but ventricular tachycardia was persistent. 4J/kg shock was given and there was transient sinus rhythm for 15-20 seconds but reverted back to ventricular tachycardia. Inj Amiodarone 5mg/kg loading dose given evoked no response. 4J/kg was repeated again. and inj Esmolol 500 mcg/kg bolus was given after which there was sinus rhythm. ECG showed sinus tachycardia with nonspecific ST/T wave changes.

The child was alert, afebrile, HR 140/minute, peripheral pulses felt, stable blood pressure. Cardiac POCUS showed full IVC, EF of 35-40% with an intracardiac mass. He was started on Dobutamine infusion at 10 mcg/kg/min followed by Esmolol infusion @ 25mcg/kg/min. Initial possibility of viral URI with viral myocarditis and SVT/VT (refractory)/ RA mass induced was considered. After stabilisation the child was started on 2/3 rd IV fluids, continued on Dobutamine, Esmolol infusion and Vitamin K.

Three hours after admission, the child developed again tachycardia (HR >270/min) with poor peripheral and central pulse. There was ventricular tachycardia on ECG. Repeat shock with 4J/kg was given under sedation, there was transient sinus rhythm for 15 seconds, then reverted back to VT, 6J /kg shock was given, VT reverted to SVT. Recovery was associated with poor GCS and gasping efforts. Infant was intubated and started on IMV, CVC secured. He was also given one more esmolol bolus followed by trial of Inj. Lignocaine and Inj. MgSO4. However, there was no response. As central pulses were feeble he was started on adrenaline infusion. NG tube was inserted and one dose of propranolol and ivabradine were administered.

An addition dose of shock was given with 5 J/kg heart reverted back to sinus rhythm. ECG showed sinus rhythm with ST/T wave changes. Esmolol infusion was hiked to 50 mcg/kg/mt. Child was continued on IMV, esmolol and dobutamine infusion. Repeat POCUS showed moderate Left ventricular systolic dysfunction. Perfusion became better and adrenaline was tapered and stopped, IV fluids were restricted then child was shifted to PICU for further care.

Initial blood investigations showed

Thrombocytosis,

1	Na	133 meq/lit
2	K	5.59 mmol/lit
3	Calcium	Normal
4	Hemoglobin	11.1 g/dl
5	Total count	12110/mm3
6	Neutrophil	30 /,
7	Lymphocyte	62
8	Platlet	5.28 Laks/mm3
9	Urea	4 mg/dl
10	Creatinine	0.43 mg dl
11	Sodium	132 meq/dl
12	Potassium	5.59 meq/dl
13	Chloride	101 meq/dl
14	Bicarbonate	19.4 meq/dl
15	Procalcitonin	Negative
16	CPK-MB	Normal
17	Coagulation profile	Normal.

Diagnosis

Refractory supraventricular tachycardia with intracardiac mass

Pediatric cardiologist opinion was obtained and advised to do echo cardiogram

ECHO cardiogram: small lesion in right atrium probable RA myxoma, moderate left ventricular dysfunction, tachycardia induced cardiomyopathy.

CECT chest: No evidence of solid mass lesion / filling defect in right atrium

Advised to continue

Esmolol and Propranolol were continued

Cardiac CT was planned after adequate hemodynomics stabilized

On day 2 of PICU stay, Cardiac POCUS showed ejection fraction 35 – 40% with mild LV dilatation, infant was started on Inj. Milrinone 0.3mcg/kg/min and dobutamine was tapered and stopped. Nasopharyngeal swab PCR was postive for RSV and negative for FLU, hence possibility of Respiratory Syncytial Virus bronchiolitis was considered. Repeat VBG showed normal lactate. To check the nature of Right atrial mass, CECT chest taken suggested no evidence of solid mass lesion / filling defect in right atrium.

On day 3 of PICU stay, during sedation window, he had GCS E4VTM6, fixing and following objects. He was given spontaneous breathing trial and tolerated well, and extubated to face mask. After extubation, child had minimal stridor, relieved by low dose adrenaline and Budecort nebulization. Child had no further SVT episodes, and esmolol infusion was gradually tapered and stopped.

On Day 4 of PICU stay, repeat cardiac pocus showed good ejection fraction of 45 – 50%. Milrinone infusion was gradually tapered and stopped. (Pediatric cardiologist planned to keep on follow-up for the RA mass lesion considering small size/ well adhered to the IAS and not causing RV inflow obstruction and advised to continue Propranolol for heart rate control)

Child was alert, active, afebrile, hemodynamically stable, no distress / hypoxia, no further SVT episodes and tolerated direct breast feeds, and shifted to HDU.Close monitoring was advised regarding (R) atrial mass lesion considering a possibility of small mass adhering to IAS and not causing hemodynamic disturbances

In HDU infant remained active, alert, and had one episode of excessive irritability associated with abnormal rolling eye movements while giving oral medication. The episode settled by itself and child became alert and active. Neurological examination was normal. Brain AF was at level. Orally accepting well. Cranial POCUS was normal. Advised MRI and EEG if symptoms reoccur.

Child was discharged in a stable condition

Condition at discharge

Child stable,
a febrile,
Hydration adequate,
Urine output adequate,
Vitals stable.

Treatment given

IV Fluids,

Midazolam + Inj. Fentanyl,
Milrinone, Inj. Dobutamine, Inj. Adrenaline, Inj. Esmolol
Ceftriaxone
Cefpodoxime
Enoxaparin
Lasix
Propranolol

Advice on discharge

Diet –Direct breast feeding

To repeat ECHO and to look for size of RA mass on follow up

Paediatric cardiologist review

S. No	Drug Name	Generic name /Strength	Route of Admin	Relationship with meal	Frequency
1	Syr. Cepodem	Cefpodoxime 50 m g/ 5 ml	Oral	After food	BD
2	Tab. Propranolol	Propranolol 6 mg (tab of 10mg in 5 Ml of water)	Oral	After food	BD

Medications advice on discharge

Conclusion

Supraventricular tachycardia is a frequently encountered cardiac arrhythmia that requires prompt recognition and timely management to prevent hemodynamic compromise and associated complications. This case highlights the importance of early diagnosis through clinical assessment and electrocardiographic evaluation, followed by appropriate acute interventions such as cardio version and pharmacological therapy. With timely treatment, patients with SVT generally have an excellent prognosis. Increased awareness among health care professionals, especially those working in emergency and critical care settings, is essential to ensure rapid intervention, reduce recurrence, and improve patient outcomes. Ongoing follow up and patient education play a vital role in long term management and prevention of recurrent episodes.

Successful management of refractory supraventricular tachycardia in a 4-month-old infant

Successful management of refractory supraventricular tachycardia in a 4-month-old infant

Suba. P1, S. J. Soniya Mercy Anbu2, Ruby Ravichandran3

Nightingale Journals

Suba. P¹, S. J. Soniya Mercy Anbu², Ruby Ravichandran³