Amiodarone is a medication that is recommended to be administered after the third shock in a shockable cardiac arrest (Vf/pVT) while chest compressions are being performed. The prescribed dose is 300 mg, given as an intravenous bolus that is diluted in 5% dextrose to a volume of 20 mL. It is important to note that amiodarone is not suitable for treating PEA or asystole.

In cases where VF/pVT persists after five defibrillation attempts, an additional dose of 150 mg of amiodarone should be given. However, if amiodarone is not available, lidocaine can be used as an alternative. The recommended dose of lidocaine is 1 mg/kg. It is crucial to avoid administering lidocaine if amiodarone has already been given.

Amiodarone is classified as a membrane-stabilizing antiarrhythmic drug. It works by prolonging the duration of the action potential and the refractory period in both the atrial and ventricular myocardium. This medication also slows down atrioventricular conduction and has a similar effect on accessory pathways.

Additionally, amiodarone has a mild negative inotropic action, meaning it weakens the force of heart contractions. It also causes peripheral vasodilation through non-competitive alpha-blocking effects.

It is important to note that while there is no evidence of long-term benefits from using amiodarone, it may improve short-term survival rates, which justifies its continued use.

Tricuspid regurgitation is characterized by a continuous murmur that spans the entire systolic phase of the cardiac cycle. This murmur is best audible at the lower left sternal edge and has a low frequency. Interestingly, the intensity of the murmur increases during inspiration and decreases during expiration, a phenomenon referred to as Carvallo’s sign.

Further Reading:

Tricuspid regurgitation (TR) is a condition where blood flows backwards through the tricuspid valve in the heart. It is classified as either primary or secondary, with primary TR being caused by abnormalities in the tricuspid valve itself and secondary TR being the result of other conditions outside of the valve. Mild TR is common, especially in young adults, and often does not cause symptoms. However, severe TR can lead to right-sided heart failure and the development of symptoms such as ascites, peripheral edema, and hepatomegaly.

The causes of TR can vary. Primary TR can be caused by conditions such as rheumatic heart disease, myxomatous valve disease, or Ebstein anomaly. Secondary TR is often the result of right ventricular dilatation due to left heart failure or pulmonary hypertension. Other causes include endocarditis, traumatic chest injury, left ventricular systolic dysfunction, chronic lung disease, pulmonary thromboembolism, myocardial disease, left to right shunts, and carcinoid heart disease. In some cases, TR can occur as a result of infective endocarditis in IV drug abusers.

Clinical features of TR can include a pansystolic murmur that is best heard at the lower left sternal edge, Carvallo’s sign (murmur increases with inspiration and decreases with expiration), an S3 heart sound, and the presence of atrial arrhythmias such as flutter or fibrillation. Other signs can include giant C-V waves in the jugular pulse, hepatomegaly (often pulsatile), and edema with lung crepitations or pleural effusions.

The management of TR depends on the underlying cause and the severity of the condition. In severe cases, valve repair or replacement surgery may be necessary. Treatment may also involve addressing the underlying conditions contributing to TR, such as managing left heart failure or pulmonary hypertension.

Adrenaline should be administered promptly once access to the circulatory system has been established in cases of non-shockable cardiac arrests such as PEA or asystole. The recommended dose is 1 mg, which can be given either as 10 mL of a 1:10,000 solution or as 1 mL of a 1:1000 solution through the intravenous (IV) or intraosseous (IO) routes.

In cases of shockable cardiac arrests like ventricular fibrillation (Vf) or pulseless ventricular tachycardia (pVT), adrenaline should be administered after the third shock has been delivered and chest compressions have been resumed. The same dose of 1 mg can be given using the same concentration options as mentioned earlier.

Subsequently, adrenaline should be administered every 3-5 minutes, alternating with chest compressions, without interrupting the compressions. The alpha-adrenergic effects of adrenaline cause constriction of blood vessels throughout the body, leading to increased pressures in the coronary and cerebral circulation.

The beta-adrenergic effects of adrenaline have positive effects on the heart, increasing its contractility (inotropic) and heart rate (chronotropic), which may also enhance blood flow to the coronary and cerebral arteries. However, it is important to note that these benefits may be counteracted by increased oxygen consumption by the heart, the potential for abnormal heart rhythms, temporary decrease in oxygen levels due to abnormal blood flow in the lungs, impaired microcirculation, and increased dysfunction of the heart after the cardiac arrest.

While there is no evidence supporting the long-term benefits of adrenaline use in cardiac arrest cases, some studies have shown improved short-term survival rates, which justifies its continued use.

Cardiac tamponade is characterized by several classical signs, including distended neck veins, muffled heart sounds, and hypotension. When neck veins are distended, it suggests that the right ventricle is not filling properly. In cases of trauma, this is often caused by the compression of air (tension pneumothorax) or fluid (blood in the pericardial space). One important distinguishing feature is the deviation of the trachea.

Further Reading:

Cardiac tamponade, also known as pericardial tamponade, occurs when fluid accumulates in the pericardial sac and compresses the heart, leading to compromised blood flow. Classic clinical signs of cardiac tamponade include distended neck veins, hypotension, muffled heart sounds, and pulseless electrical activity (PEA). Diagnosis is typically done through a FAST scan or an echocardiogram.

Management of cardiac tamponade involves assessing for other injuries, administering IV fluids to reduce preload, performing pericardiocentesis (inserting a needle into the pericardial cavity to drain fluid), and potentially performing a thoracotomy. It is important to note that untreated expanding cardiac tamponade can progress to PEA cardiac arrest.

Pericardiocentesis can be done using the subxiphoid approach or by inserting a needle between the 5th and 6th intercostal spaces at the left sternal border. Echo guidance is the gold standard for pericardiocentesis, but it may not be available in a resuscitation situation. Complications of pericardiocentesis include ST elevation or ventricular ectopics, myocardial perforation, bleeding, pneumothorax, arrhythmia, acute pulmonary edema, and acute ventricular dilatation.

It is important to note that pericardiocentesis is typically used as a temporary measure until a thoracotomy can be performed. Recent articles published suggest that pericardiocentesis has a low success rate and may delay thoracotomy, so it is advised against unless there are no other options available.

Unstable angina is characterized by the presence of one or more of the following symptoms: angina of effort occurring over a few days with increasing frequency, episodes of angina occurring recurrently and predictably without specific provocation, or an unprovoked and prolonged episode of cardiac chest pain. The electrocardiogram (ECG) may appear normal or show T-wave/ST-segment changes, and cardiac enzymes are typically within normal range.

On the other hand, stable angina is defined by central chest pain that is triggered by activities such as exercise and emotional stress. This pain may radiate to the jaw or left arm and is relieved by resting for a few minutes. It is usually brought on by a predictable amount of exertion.

Prinzmetal angina, although rare, is a variant of angina that primarily occurs at rest between midnight and early morning. The attacks can be severe and tend to happen in clusters. This type of angina is caused by coronary artery spasm, and patients may have normal coronary arteries.

Decubitus angina, on the other hand, is angina that occurs when lying down. It often develops as a result of cardiac failure due to an increased volume of blood within the blood vessels, which places additional strain on the heart.

Lastly, Ludwig’s angina is an extremely serious and potentially life-threatening cellulitis that affects the submandibular area. It most commonly arises from an infection in the floor of the mouth, which then spreads to the submandibular space.

This patient’s medical history suggests a diagnosis of acute coronary syndrome. It is important to provide pain relief as soon as possible. This can be achieved by administering GTN (sublingual or buccal), but if there is suspicion of an acute myocardial infarction (MI), intravenous opioids such as morphine should be offered.

Aspirin should be given to all patients with unstable angina or NSTEMI as soon as possible and should be continued indefinitely, unless there are contraindications such as a high risk of bleeding or aspirin hypersensitivity. A single loading dose of 300 mg should be given immediately after presentation.

For patients without a high risk of bleeding and no planned coronary angiography within 24 hours of admission, fondaparinux should be administered. However, if coronary angiography is planned within 24 hours, unfractionated heparin can be offered as an alternative to fondaparinux. For patients with significant renal impairment (creatinine above 265 micromoles per litre), unfractionated heparin should be considered, with dose adjustment based on clotting function monitoring.

Routine administration of oxygen is no longer recommended, but oxygen saturation should be monitored using pulse oximetry as soon as possible, preferably before hospital admission. Supplemental oxygen should only be given to individuals with an oxygen saturation (SpO2) below 94% who are not at risk of hypercapnic respiratory failure, aiming for an SpO2 of 94-98%. For individuals with chronic obstructive pulmonary disease at risk of hypercapnic respiratory failure, a target SpO2 of 88-92% should be achieved until blood gas analysis is available.

Bivalirudin, a specific and reversible direct thrombin inhibitor (DTI), is recommended by NICE as a potential treatment for adults with STEMI undergoing percutaneous coronary intervention.

For more information, refer to the NICE guidelines on the assessment and diagnosis of chest pain of recent onset.

In stable patients with SVT, it is recommended to first try vagal manoeuvres before resorting to drug treatment. This approach is particularly applicable to patients who do not exhibit any adverse features, as mentioned in the case above.

Further Reading:

Supraventricular tachycardia (SVT) is a type of tachyarrhythmia that originates from the atria or above the bundle of His in the heart. It includes all atrial and junctional tachycardias, although atrial fibrillation is often considered separately. SVT typically produces a narrow QRS complex tachycardia on an electrocardiogram (ECG), unless there is an underlying conduction abnormality below the atrioventricular (AV) node. Narrow complex tachycardias are considered SVTs, while some broad complex tachycardias can also be SVTs with co-existent conduction delays.

SVT can be classified into three main subtypes based on where it arises: re-entrant accessory circuits (the most common type), atrial tachycardias, and junctional tachycardias. The most common SVTs are AVNRT (AV nodal re-entry tachycardia) and AVRT (AV re-entry tachycardia), which arise from accessory circuits within the heart. AVNRT involves an accessory circuit within the AV node itself, while AVRT involves an accessory pathway between the atria and ventricles that allows additional electrical signals to trigger the AV node.

Atrial tachycardias originate from abnormal foci within the atria, except for the SA node, AV node, or accessory pathway. Junctional tachycardias arise in the AV junction. The ECG features of SVTs vary depending on the type. Atrial tachycardias may have abnormal P wave morphology, an isoelectric baseline between P waves (in atrial flutter), and inverted P waves in certain leads. AVNRT may show pseudo R waves in V1 or pseudo S waves in certain leads, with an RP interval shorter than the PR interval. AVRT (WPW) may exhibit a delta wave on a resting ECG and retrograde P waves in the ST segment, with an RP interval shorter than the PR interval. Junctional tachycardias may have retrograde P waves before, during, or after the QRS complex, with inverted P waves in certain leads and upright P waves in others.

Treatment of SVT follows the 2021 resuscitation council algorithm for tachycardia with a pulse. The algorithm provides guidelines for managing stable patients with SVT.

Orthostatic hypotension is a condition where patients feel lightheaded and may experience tunnel vision when they stand up from a lying down position. These symptoms are often worse in the morning. The patient’s history of recurrent episodes after being in a supine position for a long time strongly suggests orthostatic hypotension. There are no signs of epilepsy, such as deja-vu or jambs vu prodrome, tongue biting, loss of bladder or bowel control, or postictal confusion. The normal ECG and consistent timing of symptoms make postural orthostatic tachycardia syndrome (PAF) less likely. There are no neurological deficits to suggest a transient ischemic attack (TIA). The prodromal symptoms, such as tunnel vision and lightheadedness, align more with orthostatic hypotension rather than vasovagal syncope, which typically occurs after long periods of standing and is characterized by feeling hot and sweaty. Although carotid sinus syndrome could be considered as a differential diagnosis, as the patient’s head turning on getting out of bed may trigger symptoms, it is not one of the options.

Further Reading:

Blackouts, also known as syncope, are defined as a spontaneous transient loss of consciousness with complete recovery. They are most commonly caused by transient inadequate cerebral blood flow, although epileptic seizures can also result in blackouts. There are several different causes of blackouts, including neurally-mediated reflex syncope (such as vasovagal syncope or fainting), orthostatic hypotension (a drop in blood pressure upon standing), cardiovascular abnormalities, and epilepsy.

When evaluating a patient with blackouts, several key investigations should be performed. These include an electrocardiogram (ECG), heart auscultation, neurological examination, vital signs assessment, lying and standing blood pressure measurements, and blood tests such as a full blood count and glucose level. Additional investigations may be necessary depending on the suspected cause, such as ultrasound or CT scans for aortic dissection or other abdominal and thoracic pathology, chest X-ray for heart failure or pneumothorax, and CT pulmonary angiography for pulmonary embolism.

During the assessment, it is important to screen for red flags and signs of any underlying serious life-threatening condition. Red flags for blackouts include ECG abnormalities, clinical signs of heart failure, a heart murmur, blackouts occurring during exertion, a family history of sudden cardiac death at a young age, an inherited cardiac condition, new or unexplained breathlessness, and blackouts in individuals over the age of 65 without a prodrome. These red flags indicate the need for urgent assessment by an appropriate specialist.

There are several serious conditions that may be suggested by certain features. For example, myocardial infarction or ischemia may be indicated by a history of coronary artery disease, preceding chest pain, and ECG signs such as ST elevation or arrhythmia. Pulmonary embolism may be suggested by dizziness, acute shortness of breath, pleuritic chest pain, and risk factors for venous thromboembolism. Aortic dissection may be indicated by chest and back pain, abnormal ECG findings, and signs of cardiac tamponade include low systolic blood pressure, elevated jugular venous pressure, and muffled heart sounds. Other conditions that may cause blackouts include severe hypoglycemia, Addisonian crisis, and electrolyte abnormalities.

An abnormal QTc, which is the measurement of the time it takes for the heart to recharge between beats, is generally considered to be greater than 450 ms in males. However, some sources may use a cutoff of greater than 440 ms as abnormal in males. To further categorize the QTc, a measurement of 430ms or less is considered normal, 431-450 ms is borderline, and 450 ms or more is considered abnormal in males. Females typically have a longer QTc, so the categories for them are often quoted as less than 450 ms being normal, 451-470 ms being borderline, and greater than 470ms being abnormal.

Further Reading:

Long QT syndrome (LQTS) is a condition characterized by a prolonged QT interval on an electrocardiogram (ECG), which represents abnormal repolarization of the heart. LQTS can be either acquired or congenital. Congenital LQTS is typically caused by gene abnormalities that affect ion channels responsible for potassium or sodium flow in the heart. There are 15 identified genes associated with congenital LQTS, with three genes accounting for the majority of cases. Acquired LQTS can be caused by various factors such as certain medications, electrolyte imbalances, hypothermia, hypothyroidism, and bradycardia from other causes.

The normal QTc values, which represent the corrected QT interval for heart rate, are typically less than 450 ms for men and less than 460ms for women. Prolonged QTc intervals are considered to be greater than these values. It is important to be aware of drugs that can cause QT prolongation, as this can lead to potentially fatal arrhythmias. Some commonly used drugs that can cause QT prolongation include antimicrobials, antiarrhythmics, antipsychotics, antidepressants, antiemetics, and others.

Management of long QT syndrome involves addressing any underlying causes and using beta blockers. In some cases, an implantable cardiac defibrillator (ICD) may be recommended for patients who have experienced recurrent arrhythmic syncope, documented torsades de pointes, previous ventricular tachyarrhythmias or torsades de pointes, previous cardiac arrest, or persistent syncope. Permanent pacing may be used in patients with bradycardia or atrioventricular nodal block and prolonged QT. Mexiletine is a treatment option for those with LQT3. Cervicothoracic sympathetic denervation may be considered in patients with recurrent syncope despite beta-blockade or in those who are not ideal candidates for an ICD. The specific treatment options for LQTS depend on the type and severity of the condition.

Beta blockers are the primary treatment for long QT syndrome (LQTS). This patient probably has an undiagnosed congenital LQTS because there is no obvious cause. If there is a known cause of LQTS that can be removed, removing it may be the only necessary treatment. However, in all other cases, beta blockers are usually needed to prevent ventricular arrhythmias. Ventricular arrhythmias happen because of increased adrenergic activity. Beta blockers reduce the effects of adrenergic stimulation.

Further Reading:

Long QT syndrome (LQTS) is a condition characterized by a prolonged QT interval on an electrocardiogram (ECG), which represents abnormal repolarization of the heart. LQTS can be either acquired or congenital. Congenital LQTS is typically caused by gene abnormalities that affect ion channels responsible for potassium or sodium flow in the heart. There are 15 identified genes associated with congenital LQTS, with three genes accounting for the majority of cases. Acquired LQTS can be caused by various factors such as certain medications, electrolyte imbalances, hypothermia, hypothyroidism, and bradycardia from other causes.

The normal QTc values, which represent the corrected QT interval for heart rate, are typically less than 450 ms for men and less than 460ms for women. Prolonged QTc intervals are considered to be greater than these values. It is important to be aware of drugs that can cause QT prolongation, as this can lead to potentially fatal arrhythmias. Some commonly used drugs that can cause QT prolongation include antimicrobials, antiarrhythmics, antipsychotics, antidepressants, antiemetics, and others.

Management of long QT syndrome involves addressing any underlying causes and using beta blockers. In some cases, an implantable cardiac defibrillator (ICD) may be recommended for patients who have experienced recurrent arrhythmic syncope, documented torsades de pointes, previous ventricular tachyarrhythmias or torsades de pointes, previous cardiac arrest, or persistent syncope. Permanent pacing may be used in patients with bradycardia or atrioventricular nodal block and prolonged QT. Mexiletine is a treatment option for those with LQT3. Cervicothoracic sympathetic denervation may be considered in patients with recurrent syncope despite beta-blockade or in those who are not ideal candidates for an ICD. The specific treatment options for LQTS depend on the type and severity of the condition.