Dr. Usman's Cardiology Notes

𝐀𝐧𝐚𝐭𝐨𝐦𝐢𝐜 𝐚𝐩𝐩𝐫𝐨𝐚𝐜𝐡 𝐭𝐨 𝐬𝐥𝐨𝐰 𝐩𝐚𝐭𝐡𝐰𝐚𝐲 𝐚𝐛𝐥𝐚𝐭𝐢𝐨𝐧 𝐢𝐧 𝐀𝐕𝐍𝐑𝐓.  The septal aspect of the tricuspid annulus from the CS ostium to the His bundle is divided in posterior (Post), mid (Mid), and anterior (Ant) sections (from the RAO view). The ablation catheter is initially placed in the posterior section and RF applications are started here. Successful ablation may require progressive advancement of the ablation catheter to the mid and then to the anterior sites with increased risk of AV block in the more superior and anterior sites. The anatomic method targets the slow pathway region in the right atrial posteroseptum, guided by fixed landmarks rather than detailed electrogram criteria. Key Anatomical Landmarks 1. Triangle of Koch — the critical map: Apex: His bundle region Base: Ostium of the coronary sinus (CS) Septal leaflet of the tricuspid valve (TV) forming the third border 2. Slow pathway zone: Located inferior and posterior to the His region T...

Key Echocardiography Findings in atrial fibrillation patient Echo does not replace ECG for confirmation of AF, but several findings together can make the diagnosis highly likely. Key echocardiographic indicators: 1. Loss of atrial contraction There is no A-wave seen on mitral inflow Doppler. There is no A’ wave on TDI of the mitral annulus. LV filling is dominated by the E-wave only, and sometimes an L-wave appears in restrictive filling. 2. Irregular ventricular response Beat-to-beat variation in mitral inflow Doppler E-wave height and deceleration time. Irregular LVOT stroke volume from one beat to another. Variable cycle length with no pattern, reflecting irregular R-R intervals mechanically. 3. Left atrial changes suggesting chronic AF Marked LA enlargement. Reduced LA emptying function. Low atrial strain values. Presence of spontaneous echo contrast or thrombus especially in the appendage on TEE. 4. TEE features strongly supportive Low appendage emptying velocity often below 20–30...

  Understanding ICD Indications: A Complete Guide to Life-Saving Technology Every year, sudden cardiac death claims hundreds of thousands of lives worldwide. For many at-risk patients, an implantable cardioverter defibrillator (ICD) can be the difference between life and death. But who exactly needs this device, and when is it recommended? This comprehensive guide explores the indications for ICD implantation and helps demystify this critical cardiac intervention. ## What Is an ICD? An implantable cardioverter defibrillator is a small device, about the size of a pocket watch, that's surgically placed under the skin near the collarbone. Connected to the heart via thin wires called leads, an ICD continuously monitors heart rhythm and can deliver electrical shocks to restore normal rhythm when dangerous arrhythmias occur. Think of it as a personal emergency medical team that's always on duty, ready to restart your heart if it stops beating effectively. ## The Two Main Categories: ...

 

Following are some good references for the Modified Sgarbossa Criteria (MSC) for diagnosing myocardial infarction in the presence of wide QRS (e.g. Left Bundle Branch Block — LBBB — or paced rhythm): ✅ What is the Modified Sgarbossa Criteria The Modified Sgarbossa Criteria was proposed by Stephen W. Smith et al (2012) to improve the diagnostic accuracy of the original Sgarbossa Criteria in patients with LBBB or ventricular paced rhythm.  The key modification is replacing the “absolute ST-elevation ≥ 5 mm in a lead with a negative (discordant) QRS” rule with a proportional rule based on the ST-segment to S-wave amplitude ratio (ST/S ratio).  Using a proportional cutoff (e.g. ST/S ≤ –0.25, or ST elevation ≥ 25% of the depth of the S wave) improves sensitivity compared with the original fixed-mm rule, while maintaining high specificity.  --- 📚 Key Literature / References Reference / Source Notes / Findings Smith SW, Dodd KW, Henry TD, Dvorak DM, Pearce LA. “Diagnosis of ST-...

  True Aneurysm vs Pseudoaneurysm: Understanding the Difference in a Way That Actually Makes Sense When you hear the word aneurysm, it often brings a sense of alarm — and rightly so. But in clinical practice, not all aneurysms behave the same way. Two terms frequently come up that sound similar but are worlds apart in meaning and management: True Aneurysm and Pseudoaneurysm. Key Difference: True aneurysm = the vessel wall stretches out but stays whole. Pseudoaneurysm = the vessel wall actually tears, and a fake sac forms outside. Let’s break them down in a simple, relatable way — the kind you’d actually explain to a friend or even a patient. --- Imagine the Blood Vessel as a House Wall… 🏠 A True Aneurysm is like a wall that has stretched out… but hasn’t broken. All three layers of the arterial wall — intima, media, and adventitia — balloon outwards together. Think of it like an old wall bulging because of water damage… the wall is still intact, but it’s weak. 💥 A Pseudoaneurysm i...

KEY FACTS OF Peripartum Cardiomyopathy - PPCM Peripartum Cardiomyopathy (PPCM): The Heart Condition Every Clinician Should Recognize Pregnancy is often described as a physiological stress test for the body. While most women adapt remarkably well, a small number develop a rare but potentially life-threatening cardiac condition known as Peripartum Cardiomyopathy (PPCM). Despite improved awareness, PPCM continues to be underdiagnosed—mainly because its symptoms mimic normal pregnancy-related discomforts. In this article, we explore what PPCM is, how it presents, why it happens, and why early recognition makes all the difference. --- What Is Peripartum Cardiomyopathy? Peripartum cardiomyopathy is an idiopathic form of heart failure characterized by left ventricular systolic dysfunction that develops during a very specific period: **✔ From the last month of pregnancy ✔ To up to 5 months after delivery** Women must not have had any prior structural heart disease, and the LVEF is typically ...

Understanding the Rentrop Classification: A Guide to Coronary Collateral Circulation When a coronary artery becomes completely blocked, the heart doesn't always lose all blood supply to that area. Thanks to collateral circulation, smaller vessels can sometimes step in to provide alternate routes for blood flow. The Rentrop classification system helps cardiologists assess just how well these backup pathways are working during coronary angiography. What is the Rentrop Classification? Developed to standardize the assessment of coronary collateral vessels, the Rentrop classification grades collateral circulation on a scale from 0 to 3. This grading system is particularly important when evaluating patients with chronic total occlusions or severe coronary artery disease. The presence and quality of collateral circulation can significantly impact patient outcomes, treatment decisions, and prognosis. The Four Grades Explained Grade 0: No Visible Collaterals In Grade 0, there are no visible...

  HOMA-IR Clinical uses and interpretation of HOMA-IR? HOMA-IR is a simple surrogate marker used to estimate insulin resistance, calculated from fasting glucose and fasting insulin. ✅ Normal Values and Interpretation There is no universal cut-off. Cutoffs vary by population, ethnicity, and assay used. But clinical practice generally uses: HOMA-IR Value Interpretation < 1.0. Excellent insulin sensitivity 1.0 – 1.9. Normal insulin sensitivity 2.0 – 2.5 Early insulin resistance 2.5 – 3.9. Moderate insulin resistance ≥ 4.0 Severe insulin resistance / hyperinsulinemic state For South Asian / Middle Eastern populations, even HOMA-IR > 2.0 already suggests significant insulin resistance. Clinical Uses of HOMA-IR HOMA-IR is most useful for: 1) Diagnosing insulin resistance Especially in: Obesity Metabolic syndrome Acanthosis nigricans PCOS Pre-diabetes NAFLD / NASH Because fastin...

 Wells Criteria for Pulmonary Embolism: A Comprehensive Clinical Guide  Introduction The Wells Criteria for Pulmonary Embolism (PE) is a validated clinical prediction rule designed to help healthcare providers estimate the probability of PE in patients presenting with suggestive symptoms. Developed by Dr. Philip Wells and colleagues, this scoring system has become an essential tool in emergency departments and outpatient settings worldwide, helping clinicians make informed decisions about diagnostic testing and management. ## Understanding Pulmonary Embolism Pulmonary embolism occurs when a blood clot, typically originating from the deep veins of the legs, travels through the bloodstream and lodges in the pulmonary arteries, blocking blood flow to the lungs. PE is a life-threatening condition that requires prompt recognition and treatment. However, its symptoms can be nonspecific, making diagnosis challenging. Common presenting symptoms include sudden shortness of breath, ches...

Coronary Artery Dilation: Three Essential Terms Every Cardiac Professional Should Know The cardiac catheterization laboratory, commonly known as the cath lab, is where some of the most critical diagnostic and therapeutic procedures in cardiology take place. Among the many findings that interventional cardiologists encounter, coronary artery dilations represent a unique and clinically significant category that requires precise terminology and careful assessment. Today, we'll explore three fundamental terms that every cardiac professional should understand: coronary artery aneurysm, coronary artery ectasia, and giant coronary aneurysm. Why Precise Terminology Matters in the Cath Lab In the high-stakes environment of interventional cardiology, precise communication can literally save lives. When discussing coronary artery abnormalities, using the correct terminology ensures that the entire healthcare team understands the exact nature, extent, and severity of the pathology. This clarit...

Thte H's and T's: Reversible Causes of Cardiac Arrest Every Healthcare Professional Must Know When a patient goes into cardiac arrest, every second counts. While high-quality CPR and defibrillation are essential, they may not be enough if we fail to identify and treat the underlying cause. This is where the "H's and T's" mnemonic becomes a lifesaving tool. These 12 reversible causes of cardiac arrest represent conditions that, if identified quickly, can be treated effectively, potentially saving a patient's life. Let's explore each one in detail. Understanding the Framework The H's and T's mnemonic helps medical teams systematically search for treatable causes during resuscitation. While performing chest compressions and managing the airway, the team must simultaneously consider these potential culprits. Missing even one could mean the difference between successful resuscitation and tragic loss. The Six H's 1. Hypovolemia (Low Blood Volume)...

✅ When to use pharmacological cardioversion (PCV) PCV is intended for hemodynamically stable patients with AF — unstable patients still generally merit electrical cardioversion.  The decision between PCV vs electrical cardioversion should also reflect patient preference, underlying heart disease / structural heart disease, and risk factors including thromboembolism.  Before any rhythm control (including PCV), the patient’s thromboembolic risk must be assessed; and anticoagulation should be started (or continued) appropriately.  For patients with AF of unclear duration > 24 hours, PCV (or any cardioversion) is not recommended unless there has been “therapeutic anticoagulation for ≥ 3 weeks” or a transesophageal echocardiography (TOE) has excluded atrial thrombus.  After cardioversion, oral anticoagulation (OAC) should be continued in nearly all patients for at least 4 weeks — and long-term in those with thromboembolic risk factors, regardless of whether sinus rhyth...

tPA (Alteplase) Dosing for STEMI, Pulmonary Embolism & Stuck Prosthetic Valve tPA (alteplase) is a fibrin-specific thrombolytic used globally for rapid reperfusion in acute ischemic events. Unlike streptokinase, tPA has no antigenicity, works faster, and produces more targeted clot dissolution. Below are the standard accepted alteplase regimens for: STEMI Acute Pulmonary Embolism Prosthetic Valve Thrombosis (PVT / stuck valve) --- 1. Alteplase Dose for STEMI Two main regimens are used: the accelerated 90-minute regimen (most common) and the 3-hour regimen. --- A) Accelerated 90-Minute Regimen (Preferred) Total dose: 100 mg If weight ≥ 67 kg: 15 mg IV bolus 50 mg over 30 minutes 35 mg over the next 60 minutes If weight < 67 kg: 15 mg IV bolus Then 0.75 mg/kg over 30 minutes (max 50 mg) Then 0.5 mg/kg over 60 minutes (max 35 mg) --- B) 3-Hour Regimen (Alternative) Total dose: 100 mg over 3 hours 1 mg/kg over 60 minutes Then 1 mg/kg over the next 2 hours (Max total 100 mg) Used whe...

  Streptokinase (SK) Dosing Guide for STEMI, Pulmonary Embolism & Stuck Prosthetic Valve: A Complete Clinical Overview Streptokinase (SK) is one of the earliest and most widely used fibrinolytic agents across the world, especially in resource-limited settings. Despite the availability of newer thrombolytics like tenecteplase and alteplase, SK continues to play a major role because of its proven efficacy, affordability, and broad clinical acceptance. In this post, we break down the standard streptokinase dosing regimens for three major life-threatening conditions: ST-Elevation Myocardial Infarction (STEMI) Acute Pulmonary Embolism (PE) Thrombotic Mechanical Valve Obstruction (Stuck Valve) Each condition has specific goals and dosing strategies. Understanding these differences is crucial for safe and effective reperfusion therapy. --- 1. Streptokinase Dose for STEMI STEMI requires rapid reperfusion to salvage myocardium. Streptokinase has been used for decades as a reliable throm...

  Anticoagulation Recommendations in Thrombocytopenia: Practical Clinical Guide Anticoagulation in patients with thrombocytopenia is one of the most common real-world dilemmas across cardiology, hematology, oncology, and critical care. The challenge is to balance the risks of thrombosis—often high in cancer, AF, prosthetic valves, or VTE—against the risk of major bleeding when platelet counts are low. Modern evidence suggests that anticoagulation is often possible, even safe, at lower platelet thresholds than previously assumed, provided the intensity and agent are adjusted carefully. --- Why Thrombocytopenia Matters Platelets are essential for primary hemostasis. As counts decline, the risk of spontaneous bleeding increases, particularly below 50,000/µL. However, the risk of fatal thrombosis (e.g., stroke in AF, pulmonary embolism in cancer) also remains significant even in thrombocytopenic states. This makes a nuanced, threshold-based approach essential. --- Key Principles 1. Avo...