Dr. Usman's Cardiology Notes

Carotid Sinus Hypersensitivity (CSH) Definition Carotid sinus hypersensitivity (CSH) is an exaggerated response to carotid sinus stimulation leading to: • Excessive bradycardia (cardioinhibitory response) • Hypotension (vasodepressor response) • Or a combination of both It is an important cause of unexplained syncope, especially in elderly patients. --- Anatomy and Physiology of the Carotid Sinus • Located at the bifurcation of the common carotid artery • Contains baroreceptors sensitive to stretch • Afferent pathway: Glossopharyngeal nerve (Hering’s nerve) • Central integration: Medulla • Efferent pathway: Vagus nerve → SA/AV node Normal function: Maintains blood pressure homeostasis In CSH: Minor stimulation → exaggerated reflex --- Epidemiology • More common in age > 60 years • Male predominance • Frequently associated with hypertension • Seen in patients with recurrent unexplained falls CSH may be present in asymptomatic elderly individuals, so clinical correlation is essential....

Downsloping of the TP segment (the Spodick sign) is a classic ECG feature of acute pericarditis, reflecting diffuse subepicardial inflammation. TP Segment on ECG – Clinical Significance and Interpretation --- Introduction The TP segment is one of the most overlooked yet clinically important portions of the ECG. Although it appears electrically silent, it serves as the true isoelectric baseline against which ST-segment deviations are measured. Understanding the TP segment is essential for accurate interpretation of ischemia, pericarditis, atrial repolarization abnormalities, and subtle ST changes. --- What is the TP Segment? The TP segment is the interval between the end of the T wave and the beginning of the next P wave. Electrophysiologically, it represents: • Completion of ventricular repolarization • Electrical diastole • A period with no net electrical activity Because both atria and ventricles are electrically silent, this segment is considered the true baseline of the ECG. --- Wh...

TIMI Risk Score A Practical Guide for Clinical Use What is TIMI Risk Score? The TIMI (Thrombolysis in Myocardial Infarction) Risk Score is a bedside clinical scoring system developed to estimate the risk of death and ischemic events in patients with: • Unstable Angina (UA) / NSTEMI • STEMI It helps in: • Early risk stratification • Guiding invasive vs conservative strategy • Predicting 14-day or 30-day outcomes Developed from the TIMI Study Group trials. --- 1️⃣ TIMI Risk Score for UA / NSTEMI Developed from the TIMI 11B Trial. Each variable = 1 point (Total = 0–7) Variable Criteria Age ≥ 65 years 1 ≥3 CAD risk factors (HTN, DM, smoker, FHx, dyslipidemia) Known CAD ≥50% stenosis Aspirin use in past 7 days 1 ≥2 angina episodes in 24 hrs 1 ST deviation ≥0.5 mm 1 Elevated cardiac biomarkers Troponin positive --- Risk Interpretation (14-day risk of death/MI/urgent revascularization) Score Risk 0–1 ~5% 2 ~8% 3 ~13% 4 ~20% 5 ~26% 6–7 ~41% Clinical Use • Score ≥3 → Early invasive strategy pre...

 Athlete’s Heart vs Hypertrophic Cardiomyopathy (HCM) Distinguishing physiological cardiac adaptation from pathological hypertrophy is a high-yield clinical problem, especially in young athletes with increased LV wall thickness on echocardiography. The implications range from reassurance to sudden cardiac death prevention. --- Definitions Athlete’s Heart A benign, reversible structural and functional cardiac remodeling due to chronic intensive training (endurance or strength). It represents physiological hypertrophy. Hypertrophic Cardiomyopathy A genetic myocardial disease characterized by unexplained LV hypertrophy, myocyte disarray, and risk of arrhythmias and sudden cardiac death. --- Pathophysiology (Core Difference) Aspect Athlete’s Heart HCM Trigger Chronic training load Sarcomeric gene mutations Hypertrophy Adaptive Maladaptive Fibrosis Absent Present (interstitial/replacement) Reversibility Yes (deconditioning) No --- Echocardiographic Differences (Most Important) Feature A...

Tc-99m PYP Imaging for Cardiac Amyloidosis -- Introduction Cardiac amyloidosis is an under-recognized cause of heart failure with preserved ejection fraction, restrictive cardiomyopathy, and unexplained left ventricular hypertrophy. Tc-99m pyrophosphate (PYP) imaging has emerged as a pivotal, non-invasive test for diagnosing transthyretin cardiac amyloidosis (ATTR-CM) and has dramatically reduced the need for endomyocardial biopsy in appropriate clinical settings. --- What is Tc-99m PYP Imaging? Tc-99m PYP imaging is a nuclear scintigraphy technique that uses technetium-99m–labeled pyrophosphate, a bone-seeking tracer. In the heart, this tracer shows avid uptake in myocardium infiltrated by transthyretin amyloid, while uptake is minimal or absent in light-chain (AL) amyloidosis. --- Why is it Important? Provides non-invasive diagnosis of ATTR-CM Helps differentiate ATTR from AL amyloidosis Avoids unnecessary endomyocardial biopsy Enables early diagnosis and treatment, especially in HFp...

Brugada Algorithm for Wide-Complex Tachycardia VT vs SVT with Aberrancy Why the Brugada Algorithm Matters Wide-complex tachycardia (WCT) is ventricular tachycardia (VT) until proven otherwise. Mislabeling VT as supraventricular tachycardia (SVT) with aberrancy can lead to inappropriate therapy and hemodynamic collapse. The Brugada algorithm provides a stepwise, ECG-based approach to rapidly differentiate VT from SVT with aberrancy using standard 12-lead ECG features. --- When to Apply the Algorithm Regular WCT (QRS ≥ 120 ms) Stable or unstable patient (do not delay cardioversion in instability) No obvious pacing spikes or polymorphic rhythms --- Step-by-Step Brugada Algorithm --- Step 1: Absence of RS Complexes in All Precordial Leads (V1–V6) Look for RS complexes (an R wave followed by an S wave). If no RS complex in any precordial lead → VT Interpretation Pure monophasic R or S waves across V1–V6 strongly favor VT. --- Step 2: RS Interval > 100 ms in Any Precordial Lead Measure fr...

  Criteria of Culprit Artery in Inferior Wall STEMI Identifying the culprit artery (RCA vs LCX) in inferior wall STEMI from surface ECG helps anticipate complications, guide cath strategy, and assess myocardial area at risk. This post summarizes ECG-based criteria commonly used to differentiate RCA from LCX occlusion. ST Elevation in Leads III and II Key principle: Lead III reflects RCA territory more strongly than lead II Findings favoring RCA occlusion ST elevation in lead III > lead II ST depression in aVL greater than lead I These patterns indicate an injury vector directed inferiorly and rightward, consistent with RCA involvement. --- Role of Lateral Precordial Leads (V5–V6) --- V5 and V6 have limited value in differentiating RCA from LCX occlusion Presence of ST elevation in V5–V6 suggests: Larger myocardial area at risk Possible extension beyond isolated inferior infarction They should be interpreted as markers of infarct size rather than culprit artery. --- ST-Segment Be...