Hypothermia can cause various changes in an electrocardiogram (ECG). These changes include a slower heart rate (bradycardia), the presence of Osborn waves (also known as J waves), a prolonged PR interval, a widened QRS complex, and a prolonged QT interval. Additionally, shivering artifact, ventricular ectopics (abnormal heartbeats originating from the ventricles), and even cardiac arrest (ventricular tachycardia, ventricular fibrillation, or asystole) may occur.

Further Reading:

Hypothermic cardiac arrest is a rare situation that requires a tailored approach. Resuscitation is typically prolonged, but the prognosis for young, previously healthy individuals can be good. Hypothermic cardiac arrest may be associated with drowning. Hypothermia is defined as a core temperature below 35ºC and can be graded as mild, moderate, severe, or profound based on the core temperature. When the core temperature drops, basal metabolic rate falls and cell signaling between neurons decreases, leading to reduced tissue perfusion. Signs and symptoms of hypothermia progress as the core temperature drops, initially presenting as compensatory increases in heart rate and shivering, but eventually ceasing as the temperature drops into moderate hypothermia territory.

ECG changes associated with hypothermia include bradyarrhythmias, Osborn waves, prolonged PR, QRS, and QT intervals, shivering artifact, ventricular ectopics, and cardiac arrest. When managing hypothermic cardiac arrest, ALS should be initiated as per the standard ALS algorithm, but with modifications. It is important to check for signs of life, re-warm the patient, consider mechanical ventilation due to chest wall stiffness, adjust dosing or withhold drugs due to slowed drug metabolism, and correct electrolyte disturbances. The resuscitation of hypothermic patients is often prolonged and may continue for a number of hours.

Pulse checks during CPR may be difficult due to low blood pressure, and the pulse check is prolonged to 1 minute for this reason. Drug metabolism is slowed in hypothermic patients, leading to a build-up of potentially toxic plasma concentrations of administered drugs. Current guidance advises withholding drugs if the core temperature is below 30ºC and doubling the drug interval at core temperatures between 30 and 35ºC. Electrolyte disturbances are common in hypothermic patients, and it is important to interpret results keeping the setting in mind. Hypoglycemia should be treated, hypokalemia will often correct as the patient re-warms, ABG analyzers may not reflect the reality of the hypothermic patient, and severe hyperkalemia is a poor prognostic indicator.

Different warming measures can be used to increase the core body temperature, including external passive measures such as removal of wet clothes and insulation with blankets, external active measures such as forced heated air or hot-water immersion, and internal active measures such as inhalation of warm air, warmed intravenous fluids, gastric, bladder, peritoneal and/or pleural lavage and high volume renal haemofilter.

This patient’s ECG shows signs consistent with hyperkalemia, including broad QRS complexes, tall-peaked T waves, and bizarre p waves. It is estimated that around 10% of patients with SLE have hyperkalemia, which is believed to be caused by hyporeninemic hypoaldosteronism. Additionally, the patient has been taking a high dose of ibuprofen, which can also contribute to the development of hyperkalemia. NSAIDs are thought to induce hyperkalemia by reducing renin secretion, leading to decreased potassium excretion.

The mortality rate associated with pulmonary edema as a result of acute heart failure secondary to cardiogenic shock during hospitalization is 50%.

Further Reading:

Cardiac failure, also known as heart failure, is a clinical syndrome characterized by symptoms and signs resulting from abnormalities in the structure or function of the heart. This can lead to reduced cardiac output or high filling pressures at rest or with stress. Heart failure can be caused by various problems such as myocardial, valvular, pericardial, endocardial, or arrhythmic issues.

The most common causes of heart failure in the UK are coronary heart disease and hypertension. However, there are many other possible causes, including valvular heart disease, structural heart disease, cardiomyopathies, certain drugs or toxins, endocrine disorders, nutritional deficiencies, infiltrative diseases, infections, and arrhythmias. Conditions that increase peripheral demand on the heart, such as anemia, pregnancy, sepsis, hyperthyroidism, Paget’s disease of bone, arteriovenous malformations, and beriberi, can also lead to high-output cardiac failure.

Signs and symptoms of heart failure include edema, lung crepitations, tachycardia, tachypnea, hypotension, displaced apex beat, right ventricular heave, elevated jugular venous pressure, cyanosis, hepatomegaly, ascites, pleural effusions, breathlessness, fatigue, orthopnea, paroxysmal nocturnal dyspnea, nocturnal cough or wheeze, and Presyncope.

To diagnose heart failure, NICE recommends three key tests: N-terminal pro-B-type natriuretic peptide (NT‑proBNP), transthoracic echocardiography, and ECG. Additional tests may include chest X-ray, blood tests (U&Es, thyroid function, LFT’s, lipid profile, HbA1C, FBC), urinalysis, and peak flow or spirometry.

Management of cardiogenic pulmonary edema, a complication of heart failure, involves ensuring a patent airway, optimizing breathing with supplemental oxygen and non-invasive ventilation if necessary, and addressing circulation with loop diuretics to reduce preload, vasodilators to reduce preload and afterload, and inotropes if hypotension or signs of end organ hypoperfusion persist.

The ECG shows the following findings:
– There is ST depression in leads V1-V4 and aVR.
– There is ST elevation in leads V5-V6, II, III, and aVF.
– There is a positive R wave in leads V1 and V2, which indicates a reverse Q wave.
These ECG changes indicate that there is an acute inferoposterior myocardial infarction.

The clinical symptoms of mitral stenosis include shortness of breath, which tends to worsen during exercise and when lying flat. Tiredness, palpitations, ankle swelling, cough, and haemoptysis are also common symptoms. Chest discomfort is rarely reported.

The clinical signs of mitral stenosis can include a malar flush, an irregular pulse if atrial fibrillation is present, a tapping apex beat that can be felt as the first heart sound, and a left parasternal heave if there is pulmonary hypertension. The first heart sound is often loud, and a mid-diastolic murmur can be heard best at the apex in the left lateral position during expiration using the bell of the stethoscope.

Mitral stenosis is typically caused by rheumatic heart disease, with about two-thirds of patients being female. During pregnancy, the increase in plasma volume can lead to elevated left atrial and pulmonary venous pressures. This can exacerbate any symptoms related to mitral stenosis and potentially result in pulmonary edema, as seen in this case.

This particular patient has a high risk of experiencing an acute coronary syndrome. Therefore, it is recommended to administer aspirin at a dosage of 300 mg and clopidogrel at a dosage ranging from 300-600 mg.

Further Reading:

Acute Coronary Syndromes (ACS) is a term used to describe a group of conditions that involve the sudden reduction or blockage of blood flow to the heart. This can lead to a heart attack or unstable angina. ACS includes ST segment elevation myocardial infarction (STEMI), non-ST segment elevation myocardial infarction (NSTEMI), and unstable angina (UA).

The development of ACS is usually seen in patients who already have underlying coronary heart disease. This disease is characterized by the buildup of fatty plaques in the walls of the coronary arteries, which can gradually narrow the arteries and reduce blood flow to the heart. This can cause chest pain, known as angina, during physical exertion. In some cases, the fatty plaques can rupture, leading to a complete blockage of the artery and a heart attack.

There are both non modifiable and modifiable risk factors for ACS. non modifiable risk factors include increasing age, male gender, and family history. Modifiable risk factors include smoking, diabetes mellitus, hypertension, hypercholesterolemia, and obesity.

The symptoms of ACS typically include chest pain, which is often described as a heavy or constricting sensation in the central or left side of the chest. The pain may also radiate to the jaw or left arm. Other symptoms can include shortness of breath, sweating, and nausea/vomiting. However, it’s important to note that some patients, especially diabetics or the elderly, may not experience chest pain.

The diagnosis of ACS is typically made based on the patient’s history, electrocardiogram (ECG), and blood tests for cardiac enzymes, specifically troponin. The ECG can show changes consistent with a heart attack, such as ST segment elevation or depression, T wave inversion, or the presence of a new left bundle branch block. Elevated troponin levels confirm the diagnosis of a heart attack.

The management of ACS depends on the specific condition and the patient’s risk factors. For STEMI, immediate coronary reperfusion therapy, either through primary percutaneous coronary intervention (PCI) or fibrinolysis, is recommended. In addition to aspirin, a second antiplatelet agent is usually given. For NSTEMI or unstable angina, the treatment approach may involve reperfusion therapy or medical management, depending on the patient’s risk of future cardiovascular events.

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.

Lown-Ganong-Levine (LGL) syndrome is a condition that affects the electrical conducting system of the heart. It is classified as a pre-excitation syndrome, similar to the more well-known Wolff-Parkinson-White (WPW) syndrome. However, unlike WPW syndrome, LGL syndrome does not involve an accessory pathway for conduction. Instead, it is believed that there may be accessory fibers present that bypass all or part of the atrioventricular node.

When looking at an electrocardiogram (ECG) of a patient with LGL syndrome in sinus rhythm, there are several characteristic features to observe. The PR interval, which represents the time it takes for the electrical signal to travel from the atria to the ventricles, is typically shortened and measures less than 120 milliseconds. The QRS duration, which represents the time it takes for the ventricles to contract, is normal. The P wave, which represents the electrical activity of the atria, may be normal or inverted. However, what distinguishes LGL syndrome from other pre-excitation syndromes is the absence of a delta wave, which is a slurring of the initial rise in the QRS complex.

It is important to note that LGL syndrome predisposes individuals to paroxysmal supraventricular tachycardia (SVT), a rapid heart rhythm that originates above the ventricles. However, it does not increase the risk of developing atrial fibrillation or flutter, which are other types of abnormal heart rhythms.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, affecting around 5% of patients over the age of 70-75 years and 10% of patients aged 80-85 years. While AF can cause palpitations and inefficient cardiac function, the most important aspect of managing patients with AF is reducing the increased risk of stroke.

AF can be classified as first detected episode, paroxysmal, persistent, or permanent. First detected episode refers to the initial occurrence of AF, regardless of symptoms or duration. Paroxysmal AF occurs when a patient has 2 or more self-terminating episodes lasting less than 7 days. Persistent AF refers to episodes lasting more than 7 days that do not self-terminate. Permanent AF is continuous atrial fibrillation that cannot be cardioverted or if attempts to do so are deemed inappropriate. The treatment goals for permanent AF are rate control and anticoagulation if appropriate.

Symptoms of AF include palpitations, dyspnea, and chest pain. The most common sign is an irregularly irregular pulse. An electrocardiogram (ECG) is essential for diagnosing AF, as other conditions can also cause an irregular pulse.

Managing patients with AF involves two key parts: rate/rhythm control and reducing stroke risk. Rate control involves slowing down the irregular pulse to avoid negative effects on cardiac function. This is typically achieved using beta-blockers or rate-limiting calcium channel blockers. If one drug is not effective, combination therapy may be used. Rhythm control aims to restore and maintain normal sinus rhythm through pharmacological or electrical cardioversion. However, the majority of patients are managed with a rate control strategy.

Reducing stroke risk in patients with AF is crucial. Risk stratifying tools, such as the CHA2DS2-VASc score, are used to determine the most appropriate anticoagulation strategy. Anticoagulation is recommended for patients with a score of 2 or more. Clinicians can choose between warfarin and novel oral anticoagulants (NOACs) for anticoagulation.

Before starting anticoagulation, the patient’s bleeding risk should be assessed using tools like the HAS-BLED score or the ORBIT tool. These tools evaluate factors such as hypertension, abnormal renal or liver function, history of bleeding, age, and use of drugs that predispose to bleeding.

Adrenaline is recommended to be administered after the third shock in a shockable cardiac arrest (Vf/pVT) once chest compressions have been resumed. The recommended dose is 1 mg, which can be administered as either 10 mL of a 1:10,000 solution or 1 mL of a 1:1000 solution.

Subsequently, adrenaline should be given every 3-5 minutes, alternating with chest compressions. It is important to administer adrenaline without interrupting chest compressions to ensure continuous circulation and maximize the chances of successful resuscitation.