Please purchase the course before starting the lesson. Tachycardia is defined as a heart rate greater than what is considered normal for a child’s age. Like bradycardia, tachycardia can be life-threatening if it compromises the heart’s ability to perfuse effectively. When the heart beats too quickly, there is a shortened relaxation
phase. This causes two main problems: the ventricles are unable to fill completely, so cardiac output is lowered; and the coronary arteries receive less blood, so supply to the heart is decreased. There are several kinds of tachycardia, and they can be difficult to differentiate in children on ECG due to the elevated heart rate.Signs and symptoms of tachycardia
Sinus tachycardia
Supraventricular tachycardia
Atrial fibrillation
Atrial flutter
Ventricular
tachycardia
Pediatric tachyarrhythmias are first divided into narrow complex or wide complex tachycardia. Measure the QRS complex on a standard ECG to assess its width.
NARROW QRS COMPLEX (≤ 0.09 s) | WIDE QRS COMPLEX (> 0.09 s) |
Atrial fibrillation or Atrial flutter | Ventricular tachycardia |
Sinus tachycardia | Unusual SVT |
Supraventricular Tachycardia (SVT) |
Table 16
Narrow QRS Complex
Atrial flutter is an uncommon rhythm distinguished on an ECG as a sawtooth pattern. It is caused by an abnormal pathway that causes the atria to beat very quickly and ineffectively. Atrial contractions may exceed 300 bpm but not all of these will reach the AV node and cause a ventricular contraction.
Most often, PALS providers will have to distinguish between two similar narrow QRS complex tachyarrhythmias: sinus tachycardia and supraventricular tachycardia (SVT). SVT is more commonly caused by accessory pathway reentry, AV node reentry, and ectopic atrial focus.
SINUS TACHYCARDIA | SUPRAVENTRICULAR TACHYCARDIA |
Infant: < 220 bpm | Infant: > 220 bpm |
Child: < 180 bpm | Child: > 180 bpm |
Slow onset | Abrupt start/stop |
Fever, hypovolemia | Pulmonary edema |
Varies with stimulation | Constant, fast rate |
Visible P waves | Absent P waves |
Table 17
Wide QRS Complex
Ventricular tachycardia (VT) is uncommon in children but can be rapidly fatal. Unless the person has a documented wide complex tachyarrhythmia, an ECG with a QRS complex greater than 0.09 seconds is VT until proven otherwise. Polymorphic VT, Torsades de Pointes, and unusual SVT (SVT with wide complexes due to aberrant conduction) may be reversible, e.g. magnesium for Torsades, but do not delay treatment for VT. Any of these rhythms can devolve into ventricular fibrillation (VF). VT may not be particularly rapid (simply greater than 120 bpm) but is regular. Generally, P waves are lost during VT or become dissociated from the QRS complex. Fusion beats are a sign of VT and are produced when both a supraventricular and ventricular impulse combine to produce a hybrid appearing QRS (fusion beat) (Figure 14).
Last reviewed: 30 Sep 2022
Last updated: 18 Oct 2019
Summary
A ventricular rhythm faster than 100 bpm lasting at least 30 seconds or requiring termination due to hemodynamic instability.
ECG findings include wide QRS complex (duration >120 milliseconds) at a rate greater than 100 bpm.
Patients may have a normal cardiac output or may be hemodynamically compromised during episodes of ventricular tachycardia (VT). Presence or absence of symptoms does not differentiate VT from supraventricular tachycardia.
Torsades de pointes: polymorphic VT with a characteristic twisting morphology occurring in the setting of QT interval prolongation.
Sustained VT is usually observed in ischemic and nonischemic cardiomyopathy, but idiopathic VT may also be observed in patients without structural heart disease.
Among patients with prior myocardial infarction or nonischemic cardiomyopathy, VT is usually due to reentry involving regions of slowed conduction adjacent to scar.
Owing to the unpredictable and life-threatening nature of most etiologies of sustained VT, prophylactic implantable cardioverter defibrillator implantation is recommended in high-risk patients.
Definition
Sustained ventricular tachycardia (VT) is a ventricular rhythm faster than 100 bpm lasting at least 30 seconds or requiring termination earlier due to hemodynamic instability. VT is defined as a wide complex tachycardia (QRS 120 milliseconds or greater) that originates from one of the ventricles, and is not due to aberrant conduction (e.g., from
bundle branch block), at a rate of 100 bpm or greater. "Idiopathic" VT occurs in the absence of apparent structural heart disease (e.g., prior myocardial infarction, active ischemia, cardiomyopathy, valvular disease, arrhythmogenic right ventricular cardiomyopathy, left ventricular noncompaction, or other disorders of the myocardium), known channelopathy (e.g., long QT syndrome, Brugada syndrome, catecholaminergic polymorphic VT, short QT syndrome), drug toxicity, or electrolyte imbalance. VT
can be described as monomorphic or polymorphic. Torsades de pointes is a polymorphic VT with a characteristic twisting morphology occurring in the setting of QT interval prolongation. Sustained VT usually results in hypotension and symptoms of weakness, syncope, or palpitations; however, the arrhythmia may be present in patients who are asymptomatic and normotensive.[Figure caption and citation for the preceding image
starts]: Sustained (monomorphic) ventricular tachycardiaFrom the collection of Prof Sei Iwai; used with permission [Citation ends].
History and exam
Key diagnostic factors
- coronary artery disease
- tachycardia
- hypotension
More key diagnostic factors
Other diagnostic factors
- weak pulse
- syncope
- presyncope
- airway compromise
- impaired consciousness
- lightheadedness
- dizziness
- diminished responsiveness
- chest discomfort
- dyspnea
- asymptomatic
Other diagnostic factors
Risk factors
- coronary artery disease
- acute myocardial infarction
- left ventricular systolic dysfunction
- hypertrophic cardiomyopathy
- long QT syndrome
- short QT syndrome
- Brugada syndrome
- family history of sudden death
- mental or physical stress
- ventricular pre-excitation
- arrhythmogenic right ventricular cardiomyopathy
- electrolyte imbalance
- drug toxicity
- Chagas disease and other cardiomyopathies
More risk factors
Diagnostic investigations
1st investigations to order
- ECG
- electrolytes
- troponin I
- creatine kinase-MB
More 1st investigations to order
Investigations to consider
- transthoracic echocardiogram
- cardiac catheterization
- cardiac MRI
- electrophysiologic study
- genetic screening
More investigations to consider
Treatment algorithm
hemodynamically unstable ventricular tachycardia with a pulse
torsades de pointes
catecholaminergic polymorphic ventricular tachycardia
hemodynamically stable nonidiopathic sustained ventricular tachycardia
hemodynamically stable idiopathic sustained ventricular tachycardia
nonidiopathic: at high risk for ventricular tachycardia or history of sustained ventricular tachycardia/cardiac arrest without identifiable reversible cause
idiopathic ventricular tachycardia
Contributors
Authors
Sei Iwai, MD, FACC, FHRS
Professor of Clinical Medicine
New York Medical College
Director, Cardiac Electrophysiology
Westchester Medical Center Health Network
Valhalla
NY
DisclosuresSI is on the Biosense-Webster speakers' bureau. He receives honoraria from Biotronik, Boston Scientific, and Medtronic for lectures, and research grant support from Boston Scientific.
Acknowledgements
Prof Sei Iwai would like to gratefully acknowledge Dr Kenneth Stein and Dr Richard Keating, previous contributors to this topic.
DisclosuresKS declares he is an employee of and shareholder in Boston Scientific, a manufacturer of implantable cardioverter defibrillators and ablation catheters. RK declares that he has no competing interests.
Peer reviewers
Suneet Mittal, MD
Director
Electrophysiology Laboratory
The St. Luke's-Roosevelt Hospital Center
New York
NY
DisclosuresSM declares that he has no competing interests.
Kenneth A. Ellenbogen, MD
Kontos Professor of Cardiology
Medical College of Virginia
Richmond
VA
DisclosuresKAE declares that he has no competing interests.
Kim Rajappan, MA, MD, MRCP
Consultant Cardiologist and Electrophysiologist
Cardiac Department
John Radcliffe Hospital
Oxford
UK
DisclosuresKR declares that she has no competing interests.
Differentials
- Supraventricular tachycardia with aberrancy
- Supraventricular tachycardia with preexcitation
- Electrical artifact
More Differentials
Guidelines
- HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias
- American Heart Association web-based integrated guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Part 7: adult advanced cardiovascular life support
More Guidelines
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