Dr. Usman's Cardiology Notes

 Pericardial Fat Pad Mimicking Cardiomegaly: Cause of Increased Cardiothoracic Ratio on Chest X-Ray Introduction An increased cardiothoracic ratio (CTR) on chest X-ray (CXR) is commonly interpreted as cardiomegaly. However, not all apparent cardiac enlargement reflects true cardiac pathology. One important and often overlooked cause is a pericardial fat pad, which can enlarge the cardiac silhouette without any increase in actual heart size. Recognizing this entity is essential to avoid misdiagnosis and unnecessary investigations. --- What Is a Pericardial Fat Pad? Pericardial fat refers to adipose tissue located: Epicardial fat: between the myocardium and visceral pericardium Paracardial (mediastinal) fat: outside the parietal pericardium When excessive, this fat can project over the cardiac borders on CXR, producing a falsely increased CTR. --- Why It Increases CTR on Chest X-Ray CTR is calculated as the ratio of maximal transverse cardiac diameter to maximal thoracic diameter (no...

Adenosine Response in Regular Narrow Complex Tachycardia (NCT) 🫀⚡ Regular narrow complex tachycardia (QRS < 120 ms) is most commonly due to supraventricular tachycardias (SVTs). Adenosine is both a diagnostic and therapeutic agent in this setting because of its transient AV nodal block. Understanding the ECG response to adenosine is crucial for accurate rhythm diagnosis at the bedside, emergency department, and EP lab. --- Mechanism of Action of Adenosine Adenosine acts primarily on A1 receptors in the AV node, leading to: Hyperpolarization of AV nodal tissue Transient complete AV block Very short half-life (≈ 10 seconds) This makes adenosine ideal for unmasking atrial activity or terminating AV node–dependent tachycardias. --- Why Adenosine Is Useful in Regular NCT In regular NCT, the differential diagnosis includes: AV nodal–dependent tachycardias Atrial tachyarrhythmias with rapid ventricular response Adenosine helps by answering one key question: Is the AV node essential for ma...

  Average LDL-C reduction with lipid-lowering therapies (ESC/EAS): ■ Statins are the foundation: Moderate-intensity ≈ 30% High-intensity ≈ 50% ■ Statin + non-statin combinations markedly improve efficacy: High-intensity statin + ezetimibe ≈ 60% High-intensity statin + bempedoic acid ≈ 58% ■ PCSK9 inhibitors provide the largest incremental effect: PCSK9 mAb alone ≈ 60% With statins ± ezetimibe → 75–80% ■ Maximal LDL-C lowering (~85–86%) is achieved with quadruple therapy (high-intensity statin + ezetimibe + bempedoic acid + PCSK9 mAb). ■ Clinical implication: very-high-risk patients usually require early combination therapy to reach ESC LDL-C targets. #medical #cardiology #hearthealth #heart #fblifestyle

  Bedside Hemodynamic Assessment: An Echocardiography Guide for the ICU Bedside echocardiography has become a cornerstone of modern ICU practice. Beyond simple assessment of left ventricular ejection fraction, focused echocardiography allows real-time evaluation of pressures, congestion, systemic flow, and shock physiology. A structured approach transforms echo from a descriptive tool into a true hemodynamic monitor. --- 1. Role of Echocardiography in ICU Hemodynamics Critically ill patients often have complex, rapidly changing physiology. Invasive monitoring is not always available or reliable. Bedside echocardiography provides: • Non-invasive, repeatable hemodynamic assessment • Immediate correlation with clinical status • Guidance for fluids, inotropes, and vasopressors • Etiologic diagnosis of shock A practical framework divides assessment into two domains: 1. Pressures and congestion 2. Systemic flow and shock state --- 2. Assessing Pressures and Venous Congestion A. Inferior ...

Systolic Anterior Motion (SAM) in Hypertrophic Cardiomyopathy Definition Systolic anterior motion (SAM) refers to anterior displacement of the mitral valve apparatus toward the interventricular septum during systole, leading to dynamic left ventricular outflow tract (LVOT) obstruction and mitral regurgitation. It is a hallmark pathophysiologic feature of hypertrophic cardiomyopathy (HCM), particularly the obstructive phenotype. --- Pathophysiology of SAM SAM is not simply a consequence of septal hypertrophy; it is the result of complex interactions between ventricular geometry, mitral valve anatomy, and flow dynamics. Key mechanisms include: 1. Venturi and Drag Forces High-velocity systolic flow through a narrowed LVOT creates drag forces that pull the anterior mitral leaflet toward the septum. 2. Mitral Valve Abnormalities Elongated anterior mitral leaflet Anterior displacement of papillary muscles Increased leaflet slack These abnormalities predispose the leaflet to systolic displace...

Evolution of ECG Changes in STEMI ST-elevation myocardial infarction (STEMI) produces a characteristic, time-dependent sequence of ECG changes that reflect ongoing myocardial ischemia, injury, and eventual necrosis. Understanding this evolution is critical for early diagnosis, localization of the infarct-related artery, reperfusion decisions, and assessment of infarct age. --- 1. Hyperacute Phase (Minutes to First Hour) Key ECG features Tall, broad-based, symmetrical T waves T wave height disproportionate to QRS complex Often localized to a coronary territory ST segment may still be isoelectric or minimally elevated Pathophysiology Local extracellular potassium accumulation due to acute transmural ischemia Earliest electrical manifestation of coronary occlusion Clinical relevance Easily missed or mistaken for hyperkalemia Recognition allows ultra-early reperfusion before ST elevation becomes obvious --- 2. Acute Injury Phase (Minutes to Hours) Key ECG features ST-segment elevation in c...

 Broken Heart Syndrome (Takotsubo Syndrome, Stress Cardiomyopathy) Definition Broken heart syndrome, also known as Takotsubo syndrome (TTS), is an acute, reversible heart failure syndrome characterized by transient left ventricular systolic dysfunction, usually triggered by intense emotional or physical stress, in the absence of obstructive coronary artery disease sufficient to explain the presentation. Epidemiology Predominantly affects postmenopausal women (≈85–90%) Accounts for 1–3% of patients presenting with suspected acute coronary syndrome (ACS) Increasing recognition due to routine coronary angiography and cardiac MRI Pathophysiology (Guideline-based concepts) Exact mechanism remains multifactorial and incompletely understood. Current ESC and international consensus emphasize: Catecholamine excess Sudden surge in catecholamines leading to myocardial stunning, microvascular dysfunction, and direct myocyte toxicity Coronary microvascular dysfunction Impaired coronary flow res...