Arrhythmias and Emergency Medicine- 1 - Free MCQ Practice Test with solutions,

The heart rate is irregular. Observe the horizontal rhythm strip markings.

Right axis deviation is present.

There is a right axis deviation present. The P wave is evident and displays various morphologies. The vertical markings emphasise the different shapes of the P waves. The existence of P waves effectively excludes atrial fibrillation and paroxysmal supraventricular tachycardia.

• qRS complexes are of normal duration.
• ST segment appears normal.
• Progression of the R wave towards the lateral chest leads is abnormal.
• Deep S waves in the lateral leads suggest a potential right ventricular enlargement.

The findings indicate a diagnosis of multifocal atrial tachycardia.

In individuals with SLE, the Ro antibody can be transmitted through the placenta to the fetus, leading to potential harm to the fetus's AV node. This may cause the infant to be born with complete heart block, also known as third-degree heart block.

• The neonate presents with bradycardia.
• There is an occurrence of AV dissociation.
• Pacing is necessary during the initial days after birth.

Torsades de pointes ('Twisting of the Points'; a form of polymorphic VT linked to extended QT intervals) refers to ventricular tachycardia (VT) marked by polymorphic qRS complexes that vary in amplitude and cycle length, creating a visual effect of oscillations around the baseline. This rhythm is inherently related to QT prolongation.

• Factors contributing to Torsades de pointes include:
• Administration of various antiarrhythmic medications, particularly quinidine
• Phenothiazine usage
• Tricyclic antidepressants
• Liquid protein diets
• Intracranial incidents
• Bradyarrhythmias, especially third-degree AV block
• Can manifest as a congenital condition, often presenting with Torsades de pointes (resulting in syncope or sudden death) at a young age

The electrocardiographic signature is polymorphic VT, typically preceded by significant QT prolongation, often exceeding 0.60 seconds. These patients frequently experience multiple episodes of nonsustained polymorphic VT that are linked to recurrent syncope; however, they may also progress to VT and sudden cardiac death.

PVCs are frequently observed in both individuals with and without heart conditions, being identified in 60% of adult males during Holter monitoring.

Rare unifocal PVCs do not indicate any of the underlying conditions mentioned.

This patient has a CHADS₂ score of 5 (stroke = 2 points, age = 2 points, and 1 point for hypertension). Aspirin alone may be adequate for a stroke patient without the complication of atrial fibrillation. However, for those with atrial fibrillation, where the stroke risk approaches 30%, therapeutic anticoagulation using warfarin significantly lowers the likelihood of future strokes when compared to aspirin.

• This specific patient might qualify for either medical or electrical cardioversion.
• This process requires pretreatment with Coumadin for 3 weeks if atrial fibrillation has lasted more than 48 hours or has an unknown onset.
• Alternatively, a transesophageal echocardiogram (TEE) could be conducted to rule out the presence of a left atrial thrombus.
• Following this, cardioversion can take place, followed by maintaining warfarin anticoagulation for 4 weeks.

Lidocaine is effective for ventricular arrhythmias, but not for supraventricular ones.

• These steps were found to be inconsistent and time-consuming.
• Consequently, the 2015 AHA Guidelines for CPR recommend the immediate activation of the emergency response system.
• Start chest compressions for any unresponsive adult victim who is not breathing or only gasping.

• Defibrillation at 200 joules, followed by
• If necessary, an intravenous (IV) push of 1 mg epinephrine every 3 to 5 minutes and/or
• Vasopressin to ensure adequate brain perfusion.

• An IV push of 300 mg amiodarone or
• An IV push of lidocaine at a dosage of 1.0 to 1.5 mg/kg.

All individuals with DMD are male and typically become wheelchair-dependent by the age of 12 to 15 years, subsequently succumbing to pneumonia.

• The heart is also affected in these patients, and dilated cardiomyopathy may lead to increased dyspnoea due to associated pulmonary oedema.
• The ECG findings noted indicate muscle hypertrophy of the heart, along with global dysfunction, which exacerbates the cardiovascular condition of these patients.

ALS is excluded since it usually manifests between the ages of 30 and 40 and does not involve cardiac issues.

Asymptomatic bradycardia does not necessitate treatment. However, a patient experiencing symptomatic bradycardia, such as:

• Fatigue
• Dizziness

should receive treatment with either an injection of atropine, an injection of isoprenaline, or a pacemaker.

• Complete AV block (Stokes-Adams attacks, congenital)
• Mobitz type II block
• Ongoing AV block following anterior MI
• Symptomatic bradycardia (e.g. sick sinus syndrome)

Atrioventricular Nodal Reentrant Tachycardia is the most frequently occurring paroxysmal regular supraventricular tachycardia (SVT).

• Neck pulsations arise from the concurrent contraction of the atria and ventricles.
• This occurs against a closed tricuspid valve, resulting in a cannon A wave.
• These pulsations can be experienced as a fluttering sensation in the neck.

This phenomenon is known as the frog sign.

All individuals with mitral regurgitation experience an enlargement of the left atrium, which increases the risk of chronic atrial fibrillation. In these cases, digoxin is prescribed to manage the heart rate. However, as it can lead to prolonged AV nodal block, bradycardia may occur, potentially resulting in syncope.

Atrial fibrillation can result in an embolic stroke, which may manifest as stupor or coma accompanied by neurological deficits. If there is elevated intracranial tension (ICT) due to a stroke, bradycardia can also be observed as part of the Cushing reflex.

Nevertheless, in this scenario, the patient's presentation is characterised by syncope without any neurological deficits, which eliminates the possibility of a stroke. Subarachnoid haemorrhage (SAH) typically presents with headache, nuchal rigidity, and signs of heightened sympathetic activity.

• After-depolarisations may spread to adjacent cells due to these refractory period differences, leading to re-entrant ventricular arrhythmias such as torsades de pointes or polymorphic VT.
• Early After-Depolarisations (EADs) observed in LQTS occur due to the re-opening of L-type calcium channels during the plateau phase of the cardiac action potential.
• As adrenergic stimulation can elevate the activity of these channels, this explains the heightened risk of sudden death in individuals with LQTS during states of increased adrenergic activity (e.g., exercise, excitement), particularly when repolarisation is compromised.
• Typically, during adrenergic states, repolarising currents are also boosted to reduce the duration of the action potential. In the absence of this shortening, combined with an elevated L-type calcium current, EADs can emerge.

• ECG observations in WPW syndrome include:
• Brief PR interval
• Delta wave accompanied by a broad QRS complex
• Subsequent changes in ST and T waves
• WPW syndrome is more prevalent in males.
• This condition can manifest in a healthy heart and is also noted in cases of MVP, cardiomyopathy, and Ebstein anomaly.

• VT
• PSVT with aberrant conduction, such as AF or atrial flutter.

a. PSVT. Narrow complex tachycardia (rate> 100 bpm, qRS width < 120ms),
b. Acute management: Vagotonic maneuvers followed by IV adenosine, esmolol or verapamil (if not on B-blocker); DC shock if hemodynamicatly compromised.
c. Maintenance therapy: β-blockers or verapamil.

Choices A, C, and D will extend the AV nodal delay and result in enhanced conduction through the aberrant pathway.

Mobitz I heart block is characterised by a gradual elongation of the P-R interval.

The heart rate measures 200 beats per minute with a normal axis. There is evidence of narrow complex tachycardia accompanied by hidden P waves. Additionally, widespread ST segment depression is observed in both limb and chest leads. The patient is experiencing AV nodal re-entrant tachycardia or paroxysmal supraventricular tachycardia.

• As the patient is unconscious and displays hypotension,
• cardioversion should be performed to reinstate normal sinus rhythm.

The ECG indicates a heart rate of 200/min along with broad complex tachycardia.

• Notching at the nadir of the S wave, referred to as the Josephson sign (indicated by an arrow), is observed.
• The rabbit ear appearance (marked by a circle) is seen at the peak of the R wave.

These characteristics are associated with ventricular tachycardia.

• Choice B is expected to yield a sinusoidal pattern.
• Choice C would result in twitching ventricles.
• Choice D produces electrical alternans.

Metabolic/endocrine factors contributing to Atrioventricular Block include:

• Hyperkalemia
• Adrenal insufficiency
• Hypermagnesemia
• Hypothyroidism

Arrhythmogenic right ventricular dysplasia can impact either of the two ventricles and is a defect of desmosomal proteins. It results in epsilon waves on an ECG and may provoke ventricular tachycardia (VT). Therefore, the use of an implantable cardioverter-defibrillator (ICD) is recommended to avert sudden death.
Brugada syndrome is defined by an ST segment elevation exceeding 0.2 mV, featuring a coved ST segment and negative T waves in more than one anterior precordial lead. Patients with this condition can experience polymorphic VT in the absence of structural heart disease, necessitating an ICD.
After 40 days or more following an actual episode of myocardial infarction (MI), patients with an ejection fraction (EF) of less than 35% who exhibit inducible VT in an electrophysiological laboratory are considered candidates for an ICD. The indications for ICD include:

Coronary heart disease may result in ischaemic injury to the conduction system. The existence of non-caseating granulomas in sarcoidosis causes harm to the conduction system. Myxedema cardiomyopathy is linked with a reversible type of heart block that reacts positively to thyroxine replacement. Therefore, by the process of elimination, the answer is Cushing syndrome.

The initial step of the BLS algorithm is outlined in the question (Highlighted Text).

• BLS Healthcare Provider
• Adult Cardiac Arrest Algorithm - 2015 Update

• Respiratory system: Symptoms resembling asthma, including coughing
• GIT: Diarrhoea, peptic ulcer disease (PUD), nausea with vomiting
• CVS: Angina, arrhythmias, coronary artery disease (CAD), extrasystoles, hypertension
• Eyes: Amblyopia and potential blindness
• Women: Osteoporosis, pregnancy-induced hypertension (PIH), preterm labour, and congenital malformations

• Nicotine sulfate used in insecticides
• Green tobacco sickness (affecting tobacco harvesters handling wet tobacco leaves)
• Incorrect usage of nicotine patches
• Ingesting nicotine chewing gum

The ECG displays a heart rate of 200 beats per minute with a normal axis. A broad qRS complex measuring 160 msec is observed. Additionally, the R wave exhibits a rabbit ear appearance, which is characteristic of Ventricular tachycardia.

According to ACLS guidelines, qRS synchronous electrical cardioversion is indicated for Ventricular tachycardia under the following circumstances:

• Presence of hypotension
• Impaired consciousness
• Pulmonary oedema

Amiodarone is the preferred drug of choice for stable VT.

• Although a PVC can indicate reduced oxygenation to the myocardium, they are often benign and may occur in otherwise healthy hearts.
• The prevalence of PVCs tends to increase with age.
• A PVC may be experienced as a 'skipped beat' or sensed as palpitations in the chest.

The electrocardiographic characteristics of various SVTs include:

• Sinus tachycardia: Heart rate over 100 bpm; P waves resemble those of sinus rhythm.
• Inappropriate sinus tachycardia (IST): Similar findings to sinus tachycardia; P waves resemble those of sinus rhythm.
• Sinus nodal reentrant tachycardia (SNRT): P waves resemble those of sinus rhythm; abrupt onset and offset.
• Atrial tachycardia: Heart rate between 120 and 250 bpm; P-wave morphology differs from sinus rhythm; typically long RP interval; AV block does not terminate the tachycardia.
• Multifocal atrial tachycardia: Heart rate between 100 and 200 bpm; three or more distinct P-wave morphologies.
• Atrial flutter: Atrial rate of 200 to 300 bpm; flutter waves; AV conduction ratio of 2:1 or 4:1.
• Atrial fibrillation: Irregularly irregular rhythm; absence of discernible P waves.
• AV Nodal Reentrant Tachycardia (AVNRT): Heart rate of 150 to 200 bpm; P wave located either within the QRS complex or shortly after it; short RP interval in typical AVNRT and long RP interval in atypical AVNRT.
• AV reentrant tachycardia (AVRT): Heart rate of 150 to 250 bpm; narrow QRS complex in orthodromic conduction and wide QRS in antidromic conduction; diagnosis ruled out by AV block during SVT; P wave appears after the QRS complex.

• Correcting electrolyte imbalances
• Administering Mg sulfate
• Utilising overdrive pacing