Cardio 1 Arrhythmia # Flashcards
What are the normal ranges for the QRS complexes on an ECG?
Rate: Normal = 60-100 bpm
Regularity: R-R interval should be the same.
Normal vs. Wide: A wide QRS indicates ventricular tachycardia.
What are the characteristics of P-waves in a normal ECG?
In Normal Sinus Rhythm, the P-wave should appear before every QRS complex, be upright in lead II, and biphasic in V1.
PR interval: 0.12–0.21 secs.
QT interval: Less than 0.4 secs.
Every P-wave should be followed by a QRS complex.
What is the normal ECG appearance for sinus tachycardia?
Heart rate: >100 bpm.
P-wave followed by QRS, regular R-R interval.
Narrow QRS.
Camel hump appearance: The P-wave merges with the T-wave.
What are some causes of sinus tachycardia?
Sympathetic activation or vagal withdrawal on the SA node.
Conditions like increased sympathetic tone (e.g., exercise, anxiety, pregnancy), alcohol use, and use of stimulants (e.g., caffeine).
Systemic causes: fever, hypotension, hypovolemia, anemia, thyrotoxicosis, congestive heart failure (CHF), myocardial infarction (MI), shock, pulmonary embolism.
How is sinus tachycardia treated?
Treatment should focus on addressing the underlying cause.
Beta blockers can be used if the tachycardia is symptomatic, or calcium channel blockers (CCBs) can be used if beta blockers are contraindicated.
What is respiratory sinus arrhythmia?
It is a variation in sinus rhythm with respiration.
Inspiration leads to faster heart rate, while expiration slows it down.
What are the characteristics of paroxysmal supraventricular tachycardia (SVT)?
Abrupt onset and offset, typically seen in young patients with no structural heart disease.
Regular rhythm with a heart rate around 250 bpm.
Narrow QRS.
P-wave may be hidden due to the fast heart rate, and ST depression may be observed.
What are the two types of paroxysmal SVT?
AVRT (Atrioventricular Reentry Tachycardia): Anatomical re-entry via an accessory pathway between the atria and ventricles (e.g., Wolf-Parkinson-White syndrome).
AVNRT (Atrioventricular Nodal Reentry Tachycardia): Functional reentry within the AV node, more common.
How is paroxysmal SVT treated?
First-line treatment: Vagal maneuvers like carotid massage. If unsuccessful, IV adenosine is administered.
Second-line treatment: IV beta blockers, diltiazem, or verapamil.
If the patient is unstable, emergency cardioversion is required.
Long-term management: Ablation of the accessory pathway is preferred for curing SVT.
❌
Vagal maneuvers are techniques used to stimulate the vagus nerve and can help slow down the heart rate, often used for managing supraventricular tachycardias (SVT), such as paroxysmal atrial tachycardia (PAT) or AV nodal reentrant tachycardia (AVNRT). Here are some examples of vagal maneuvers:
- Valsalva Maneuver
• How to do it: Inhale deeply, hold your breath, and bear down as if you’re having a bowel movement. This increases pressure in the chest, which can stimulate the vagus nerve and slow the heart rate.
• When to use it: Often used for patients with SVT to break the arrhythmia.
• Technique:
• Have the person sit upright or lie flat.
• Instruct the patient to take a deep breath and exhale forcefully while keeping their mouth and nose closed. - Carotid Sinus Massage
• How to do it: Gently massage one side of the neck over the carotid artery (just below the angle of the jaw) for 5-10 seconds. This stimulates the vagus nerve and can slow the heart rate.
• When to use it: This is usually performed by a healthcare provider, especially in the case of SVT or in emergencies.
• Caution: This maneuver should not be performed in patients with a history of carotid artery disease or stroke risk. - Diving Reflex (Cold Water Immersion)
• How to do it: Submerge the face in cold water, or place a cold, wet cloth over the face, particularly around the eyes and forehead. This can trigger the diving reflex, which slows the heart rate.
• When to use it: Used in some emergency settings or in the presence of a healthcare provider, it may help to terminate an arrhythmia. - Coughing
• How to do it: Instruct the patient to cough forcefully. The act of coughing increases intra-abdominal pressure, stimulating the vagus nerve.
• When to use it: It can sometimes help in terminating certain types of SVT. - Gag Reflex
• How to do it: Stimulating the back of the throat can trigger the vagus nerve. This is often done by a healthcare provider using a tongue depressor or similar instrument.
• When to use it: In some emergency situations, although it is less commonly used than other maneuvers. - Squatting
• How to do it: The patient can squat down and then stand up slowly. This maneuver increases vagal tone and can help slow the heart rate.
• When to use it: Sometimes used in children with certain types of SVT. - Breathing Exercises (Slow, Deep Breaths)
• How to do it: Inhale slowly through the nose, hold for a few seconds, and then exhale slowly through the mouth. Repeating this technique can help activate the parasympathetic nervous system, which can slow the heart rate.
• When to use it: This can be helpful in reducing anxiety and sometimes in managing episodes of tachycardia.
These maneuvers are typically used under medical supervision or with professional guidance, especially if there is a history of arrhythmia or cardiovascular conditions. If the heart rate does not return to normal after performing vagal maneuvers, it is important to seek medical assistance.
What are the characteristics of atrial fibrillation (A. Fib) on an ECG?
Irregularly irregular rhythm.
No distinct P-waves, only fine oscillations.
Narrow QRS complexes.
Can be fast or slow depending on AV node conduction.
What are the most feared complications of atrial fibrillation?
Ventricular fibrillation.
Embolism leading to stroke.
What are the symptoms of atrial fibrillation?
Palpitations.
Fatigue.
Dyspnea (shortness of breath).
Syncope (fainting).
Atrial fibrillation may also precipitate or worsen heart failure.
What are the common causes of atrial fibrillation?
Cardiac causes: MI, mitral stenosis, hypertension.
Non-cardiac causes: Thyrotoxicosis, pulmonary embolism, alcohol, and hypokalemia.
How is atrial fibrillation diagnosed?
ECG is the primary tool to diagnose atrial fibrillation.
If a new diagnosis is confirmed, an echocardiogram is needed to assess cardiac function and rule out underlying structural heart disease.
If atrial fibrillation is suspected but not confirmed on ECG, a Holter monitor may be used.
What is the treatment approach for atrial fibrillation?
If the patient is hemodynamically unstable: Immediate DC (direct current) cardioversion.
If stable:
1. Rate control: Beta blockers (BB), calcium channel blockers (CCB), or digoxin.
2. Rhythm control:
• Electrical: DC cardioversion.
• Pharmacological: Amiodarone (if structural heart disease), flecainide, or propafenone (if no heart disease).
3. Anticoagulation:
• For valvular A. Fib (e.g., with prosthetic valves or moderate-severe mitral stenosis), use warfarin or NOACs (Non-vitamin K oral anticoagulants).
• For non-valvular A. Fib, anticoagulation is guided by the CHA₂DS₂-VASc score.
• Score of 0: No anticoagulation needed.
• Score of 1: Use aspirin.
• Score of 2 or more: Use warfarin or NOACs.
How is atrial fibrillation managed long-term?
Long-term treatment should involve rate and rhythm control, as well as anticoagulation therapy to prevent thromboembolic events like stroke.
What are the characteristics of atrial flutter on an ECG?
No distinct P-waves, but saw-toothed flutter waves are seen.
Always some degree of AV block (e.g., 2:1, 3:1, 4:1).
A typical rate: 150 bpm with a 2:1 block (results in a 75 bpm ventricular rate).
What are the common causes of atrial flutter?
Underlying heart disease, such as cardiomyopathy, COPD, hyperthyroidism, and hypertension.
How is atrial flutter treated?
If unstable (e.g., hypotension, CHF, or angina): Electrical cardioversion.
If stable:
1. Rate control: Beta blockers, diltiazem, verapamil, or digoxin.
2. Chemical cardioversion: Sotalol, amiodarone, or class I antiarrhythmics.
3. Anticoagulation: Follow the same guidelines as for atrial fibrillation.
4. Long-term management: Antiarrhythmic drugs like amiodarone, flecainide, propafenone, or radiofrequency ablation.
What is multifocal atrial tachycardia?
A rapid, irregular atrial rhythm originating from multiple ectopic foci within the atria.
Most commonly seen in patients with severe COPD or congestive heart failure.
What are the characteristics of multifocal atrial tachycardia on an ECG?
Irregularly irregular rhythm with varying PP, PR, and RR intervals.
No distinct flutter waves.
At least 3 different P-wave morphologies in the same lead.
What is the treatment for multifocal atrial tachycardia?
It is typically treated by addressing the underlying condition, such as improving lung function in COPD or managing heart failure.
Control of the heart rate may be achieved with medications like beta blockers or calcium channel blockers.
Considered a poor prognostic sign when developing during acute illness.
What is ventricular tachycardia (VT) on an ECG?
VT is characterized by 3 or more consecutive premature ventricular beats.
Regular rhythm with a rate usually between 140-200 bpm.
Wide, bizarre-shaped QRS complexes.
Can be classified into monomorphic VT (more common) and polymorphic VT (e.g., Torsades de Pointes).
What are the symptoms of ventricular tachycardia?
Dizziness.
Syncope (fainting).
Shortness of breath.
Chest pain.
Palpitations.
In severe cases, it can lead to sudden death.
