Tachycardia (Tachyarrhythmia) is defined as a rhythm with a heart rate greater than 100 bpm.
The systematic approach algorithm is used to direct the care of the critically-ill or injured child. However, once it is recognized that an infant or child is experiencing symptomatic tachycardia, the tachycardia algorithm is used to simplify and streamline the evaluations and interventions to be carried out.
PALS Tachycardia Algorithm with a Pulse:
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Tachycardia with a Pulse Diagram
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Evaluate:
Tachycardia vs. Tachyarrhythmia:
Tachycardia:
Tachycardia is a term used to describe any heart rate that is rapid compared with the normal heart rate that should be present. A “normal” rate is determined by the child’s/infant’s age. “Normal” for the patient may also vary depending on the child’s baseline.
Sinus Tachycardia is the basic rhythm that can be classified as tachycardia and is not associated with an arrhythmia.
Tachyarrhythmia:
A tachyarrhythmia is an abnormally rapid heartbeat accompanied by an irregular rhythm. The electrical impulse of the rhythm may have its origin in the atria or the ventricles.
Signs & Symptoms:
Sinus tachycardia (ST) is typically a normal response to fever and other forms of stress that increase the metabolic demands of the infant or child. ST will not display a fixed rate but will rise and fall as the demands of the body change. ST in infants and children is common and results from exercise, illness, metabolic stress, etc.
Tachyarrhythmias in infants and children can be difficult to detect until cardiac output becomes significantly compromised.
Symptoms in children that may be present include palpitations, chest pain, dizziness, light-headedness, and syncope. Signs in infants that may be seen include fatigue, shortness of breath, and poor feeding.
Signs that may be present are typically associated with compromised cardiac output and hemodynamic instability. These include hypotension, altered mental status, and other signs of shock.
There are three problems caused by prolonged periods of tachycardia.
- Poor cardiac output: Decreased ventricular filling time during diastole leads to a reduced stroke volume and subsequent reduced cardiac output.
- Decreased blood flow to the heart muscle: Blood flow to the heart muscle takes place primarily during diastole, and diastole is compromised because of the extreme heart rate.
- Increased myocardial oxygen demand: The rapid heart rate leads to further myocardial dysfunction due to the increased myocardial oxygen demand.
**(When tachyarrhythmias go untreated they can result in cardiogenic shock.)**
Identify:
When the symptoms discussed above are recognized and you have identified that the patient has tachycardia, it is important to determine the nature of the tachycardia or tachyarrhythmia. Correct identification of the tachycardia or tachyarrhythmia determines the interventions that will be carried out within the tachycardia algorithms. The common tachyarrhythmias that occur in infants and children and that are discussed here include:
- Sinus tachycardia
- Supraventricular tachycardia
- Atrial flutter
- Ventricular tachycardia
- Wide-complex QRS tachycardia
Once a tachyarrhythmia is recognized, identify whether any life-threatening conditions exist. Indicators include signs of shock, hypotension, changes in the level of consciousness, etc.
Intervene:
Initial interventions:
The interventions for the initial management of both stable and unstable tachyarrhythmias are identical to the treatment for any critically-ill child. Begin with the support of the airway, breathing, and circulation and treating the underlying cause of the tachyarrhythmia.
Specific interventions include:
- Maintain an open airway, provide oxygenation and ventilation support
- Monitor oxygen saturation
- Monitor rhythm (attach ECG monitor/defibrillator)
- Obtain 12-Lead ECG (if possible)
- Establish IV/IO access
- Obtain pertinent laboratory studies (studies that may be pertinent include potassium, ionized calcium, magnesium, and glucose. An ABG may also be necessary to assess the status of the pH)
- Begin consideration of medications for use within the appropriate tachycardia algorithm
- Identify and treat any underlying reversible cause of the tachyarrhythmia
Critical interventions:
Critical interventions for patients experiencing tachyarrhythmias are determined by the degree to which the tachyarrhythmia is compromising perfusion. Use the appropriate pathway within the tachycardia algorithm to determine the interventions necessary. (see diagram below)
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Specific critical interventions commonly used in the treatment of tachyarrhythmias include:
- Vagal maneuvers for specific types of SVT
- Synchronized cardioversion
- Medication administration (Antiarrhythmics)
Click to review the algorithm, and click again to close the diagram.
Tachycardia with a Pulse Diagram
or Members Download the Hi-Resolution PDF Here.
amirhossein hashemi says
hello there ,
before everything i should say this site is perfect … i say you thank you for all you did and doing …
my english is not good sorry
i have a question about psvt
when we have a patient .. for example 41 years old man with PR 180 and BP= 80/60 and it is narrow and regular complex ..pateint has chest pain and feeling dyspnea .. i mean he is not stable .. in this case the first thing is vagal maneuver and adenosine …. and the secound step is synchronised dc shock .. my question is in here .. in this case for delivering shock we have to use sadative drugs like banzodiazepins .. ( in our ambulances we have only diazepam and midazolam ) i am worry the effect of banzodiazpins on blood pressure .. i hope i could say my mean problem .. can i use for example midazolam in this case ? ( BP=80/60 ) …. thnk you again
ACLS says
In the case you’ve described, administering benzodiazepines for sedation before synchronized cardioversion requires careful consideration due to the patient’s already low blood pressure (80/60 mmHg). While sedation is important for patient comfort during cardioversion, the potential hypotensive effects of benzodiazepines must be weighed against the need for immediate treatment.
Benzodiazepines, including midazolam, can cause a decrease in blood pressure:
1. Midazolam has been associated with a dose-dependent reduction in blood pressure, particularly in older patients[1][2].
2. Even low doses of midazolam can cause significant hypotension in some patients[3].
3. The hypotensive effect is more pronounced with intravenous administration[2].
Given the patient’s unstable condition (chest pain, dyspnea) and low blood pressure:
1. Prioritize cardioversion: The immediate need to treat the presumed supraventricular tachycardia (based on the narrow complex and rate of 180) may outweigh the risks of sedation[5].
2. Minimal sedation: If sedation is deemed necessary, use the lowest effective dose of midazolam[6].
3. Alternative options: Consider using etomidate instead of benzodiazepines if available, as it has less effect on blood pressure[3].
4. **Prepare for hypotension**: Have vasopressors ready and be prepared to provide fluid resuscitation if blood pressure drops further[5].
5. Continuous monitoring: Closely monitor the patient’s vital signs, especially blood pressure and oxygen saturation, during and after the procedure[7].
Recommendation
If sedation is absolutely necessary and only benzodiazepines are available:
1. Use midazolam at the lowest possible dose (e.g., 1-2 mg IV initially)[6].
2. Titrate slowly and carefully while monitoring blood pressure continuously[7].
3. Be prepared to manage potential hypotension with fluids and vasopressors[5].
4. Consider proceeding with cardioversion without sedation if the risk of further hemodynamic compromise is too high.
Remember, the primary goal is to treat the underlying arrhythmia causing the patient’s instability. In some cases, successful cardioversion may actually improve blood pressure by restoring normal sinus rhythm[5].
Above information curated is of Perplexity reviewed and edited by this author.
Sources:
[1] Benzodiazepines Reduce Blood Pressure in Short Term – PubMed https://pubmed.ncbi.nlm.nih.gov/37581768/
[2] Hemodynamic characteristics of midazolam, propofol, and … https://pmc.ncbi.nlm.nih.gov/articles/PMC3828053/
[3] Midazolam is more likely to cause hypotension than etomidate in … https://pmc.ncbi.nlm.nih.gov/articles/PMC1726487/
[4] Midazolam use in the emergency department – PubMed https://pubmed.ncbi.nlm.nih.gov/2302291/
[5] Benzodiazepine Consumption Is Associated With Lower Blood … https://academic.oup.com/ajh/article-abstract/31/4/431/4564985?redirectedFrom=fulltext&login=false
[6] Effect of a low dose of midazolam on high blood pressure in dental … https://pubmed.ncbi.nlm.nih.gov/27006286/
[7] Midazolam (injection route) – Mayo Clinic https://www.mayoclinic.org/drugs-supplements/midazolam-injection-route/description/drg-20064813
[8] effects of benzodiazepines on orthostatic blood pressure in older … https://journals.lww.com/jhypertension/abstract/2021/04001/effects_of_benzodiazepines_on_orthostatic_blood.1117.aspx
[9] Midazolam Side Effects: Common, Severe, Long Term – Drugs.com https://www.drugs.com/sfx/midazolam-side-effects.html
[10] [PP.16.16] REGULAR BENZODIAZEPINES CONSUMPTION … https://journals.lww.com/jhypertension/Abstract/2017/09002/_PP_16_16__REGULAR_BENZODIAZEPINES_CONSUMPTION.649.aspx
Kind regards,
Jeff
amirhossein hashemi says
hello dear sir. and thank you for your complete and very useful answer .
Irka7 says
Hi there,
I’m kind of confused. In the Tachy Algorithm for pt with pulse/poor perfusion, where it says “presume VT”(right branch), then next step is to determine if pt is unstable (hypotension, LOC change, signs of shock). My question is: if they are with pulse and inadequate perfusion- are the not considered unstable anyway, namely because of hypoperfusion?
What am I missing? THanks in advance!
ACLS says
Yes you are correct. Tachycardia with a pulse can be either adequate perfusion or inadequate perfusion. Determination of whether the patient has adequate perfusion or inadequate perfusion will determine the intervention and the algorithm that you will follow.
Kind regards,
Jeff
Jody says
Very belpful site,,,I depend mainly on it, and I pass with high score ,,,, ,only one thing need to be added, chapter of team dynamics, not mentioned here