Dr. Usman's Cardiology Notes

  Role of Mavacamten in Hypertrophic Cardiomyopathy (HCM) Mavacamten is a first-in-class cardiac myosin inhibitor used in the treatment of symptomatic obstructive hypertrophic cardiomyopathy (HCM). It targets the underlying pathophysiology of the disease rather than only treating symptoms. --- Mechanism of Action In HCM, excessive interaction between actin and myosin leads to hypercontractility and impaired relaxation of the myocardium. Mavacamten works by: • Inhibiting cardiac myosin ATPase activity • Reducing actin–myosin cross-bridge formation • Decreasing hypercontractility of the left ventricle This leads to: • Reduction in LV outflow tract (LVOT) obstruction • Improvement in diastolic relaxation • Decrease in myocardial energy consumption --- Clinical Effects Mavacamten has been shown to: • Reduce LVOT gradient • Improve NYHA functional class • Improve exercise capacity (peak VO₂) • Reduce symptoms such as dyspnea and chest pain --- Key Clinical Trial The EXPLORER‑HCM trial d...

ICD Indications in Hypertrophic Cardiomyopathy (HCM) Hypertrophic cardiomyopathy (HCM) is one of the most common inherited cardiac disorders and an important cause of sudden cardiac death (SCD), particularly in young individuals and athletes. Implantable cardioverter-defibrillator (ICD) therapy is the most effective strategy for preventing SCD in these patients. Current recommendations are mainly derived from the American Heart Association and American College of Cardiology guidelines. --- Purpose of ICD in HCM The primary role of an ICD in HCM is prevention of sudden cardiac death due to malignant ventricular arrhythmias such as ventricular tachycardia or ventricular fibrillation. ICD therapy is used in two situations: • Secondary prevention • Primary prevention (based on risk stratification) --- 1. Secondary Prevention ICD ICD implantation is strongly recommended (Class I indication) in HCM patients with any of the following: • Prior cardiac arrest due to ventricular fibrillation • S...

  PAINESD Score for Assessing Hemodynamic Instability Risk in Ventricular Tachycardia Ablation Introduction Catheter ablation for ventricular tachycardia (VT) can precipitate acute hemodynamic decompensation (AHD), particularly in patients with severe structural heart disease. To predict this risk before the procedure, the PAINESD score was developed. It is a validated clinical risk score used to estimate the likelihood of periprocedural hemodynamic instability during VT ablation and helps guide decisions regarding mechanical circulatory support (MCS) such as Impella or ECMO. --- Components of the PAINESD Score PAINESD is an acronym derived from the key predictors of hemodynamic compromise. Parameter Points P – Pulmonary disease (COPD) 5 A – Age > 60 years 3 I – Ischemic cardiomyopathy 6 N – NYHA Class III or IV heart failure 6 E – Ejection Fraction < 25% 3 S – VT Storm 5 D – Diabetes Mellitus 3 Maximum possible score: 31 points --- Risk Stratification PAINESD Score Risk of A...

  Triad of Hypothyroidism  Hypothyroidism is a common endocrine disorder characterized by reduced thyroid hormone production, leading to a generalized slowing of metabolic processes. Although the clinical presentation can be broad and nonspecific, a classic and easily remembered clinical combination is the Triad of Hypothyroidism, which includes weight gain, fatigue, and cold intolerance. Recognizing this triad can help clinicians suspect hypothyroidism early and prompt appropriate laboratory evaluation. --- Weight Gain Weight gain in hypothyroidism is primarily due to reduced basal metabolic rate and accumulation of interstitial fluid rather than true fat deposition alone. Thyroid hormones normally regulate energy expenditure and lipid metabolism. When hormone levels fall, metabolic activity decreases, resulting in gradual weight gain. Patients often report difficulty losing weight despite unchanged diet or activity levels. --- Fatigue Fatigue is one of the most common presen...

Mechanical Complications of Myocardial Infarction Mechanical complications are rare but life-threatening consequences of acute myocardial infarction (MI). They usually occur within the first week after MI, particularly in patients with delayed reperfusion or large transmural infarctions. Early recognition is critical because most cases require urgent surgical intervention. --- Types of Mechanical Complications 1. Papillary Muscle Rupture Papillary muscle rupture leads to acute severe mitral regurgitation (MR) due to loss of leaflet support. Key Points • Usually occurs 2–7 days after MI • Most commonly involves the posteromedial papillary muscle because it has single blood supply from the PDA • Causes sudden pulmonary edema and cardiogenic shock Clinical Features • Acute dyspnea • Hypotension • Loud holosystolic murmur at apex radiating to axilla Diagnosis • Echocardiography shows flail mitral leaflet and severe MR. Management • Urgent mitral valve surgery • Hemodynamic stabilization wi...

Intracardiac Echocardiography (ICE) – A Practical Overview Download PDF of all the Key Views >> What is Intracardiac Echocardiography (ICE)? Intracardiac echocardiography (ICE) is an invasive ultrasound imaging technique in which a specialized ultrasound catheter is introduced into the heart via the venous system to obtain real-time, high-resolution images of cardiac structures. It is widely used in electrophysiology (EP) procedures and structural heart interventions because it provides direct visualization of intracardiac anatomy without the need for general anesthesia or esophageal intubation. --- ICE Catheter and Access ICE is performed using a phased-array ultrasound catheter inserted most commonly through the femoral vein. Typical catheter characteristics: Size: 8–10 Fr Imaging frequency: 5–10 MHz Provides 90° sector imaging Advanced catheters allow 4-way steering The catheter is usually positioned in the right atrium, from where multiple cardiac structures can be visualized...

AHA / ACC / HRS Guideline–Based Indications for Implantable Cardioverter Defibrillator (ICD) (Adapted from American Heart Association / American College of Cardiology / Heart Rhythm Society ventricular arrhythmia and sudden cardiac death guidelines) --- 1. Secondary Prevention (Class I Indications) ICD is recommended in patients who have already experienced life-threatening ventricular arrhythmias not due to reversible causes. Indications • Survivors of cardiac arrest due to VF or hemodynamically unstable VT • Sustained VT with syncope or hemodynamic instability • Sustained VT with structural heart disease • Spontaneous sustained VT even if hemodynamically stable Important condition • No reversible cause (e.g., acute ischemia, electrolyte imbalance, drug toxicity) --- 2. Primary Prevention (Class I Indications) ICD recommended to prevent sudden cardiac death in high-risk patients. Ischemic Cardiomyopathy • LVEF ≤35%, NYHA II–III, at least 40 days after MI, on optimal medical therapy, s...