Dr. Usman's Cardiology Notes

Extracardiac uses of ranolazine 1. Neuropathic pain Blocks late Na⁺ current in neurons Reduces neuronal hyperexcitability Studied in diabetic neuropathy and chronic pain syndromes 2. Myotonia (off-label) Decreases skeletal muscle membrane excitability Helpful in myotonic disorders when mexiletine is not tolerated 3. Skeletal muscle cramps Reduces repetitive muscle fiber firing Anecdotal benefit in chronic painful cramps 4. Glycemic control (metabolic effect) Improves insulin sensitivity Lowers HbA1c in patients with diabetes (observed in trials) Mechanism: altered cellular Na⁺/Ca²⁺ handling and metabolism 5. Pulmonary hypertension (investigational) Improves right ventricular diastolic function May reduce pulmonary vascular remodeling via Na⁺/Ca²⁺ modulation 6. Neuroprotection (experimental) Late Na⁺ current inhibition may reduce neuronal calcium overload Studied in ischemia-related neuronal injury (preclinical data) Key concept Ranolazine’s late sodium current (INa-late) inhibition exp...

Conditions in which you should give anticoagulation in AF regardless of CHA₂DS₂-VASc score 1. Hypertrophic cardiomyopathy (HCM) 2. Fontan circulation 3. Systemic right ventricle 4. Intracardiac repair in congenital heart disease 5. Cyanotic heart disease 6. After AF ablation – minimum 8 weeks 7. After cardioversion – minimum 4 weeks 8. Mechanical prosthetic heart valve 9. Moderate or severe mitral stenosis 10. Anticoagulation for other indications   • Deep vein thrombosis (DVT)   • Pulmonary embolism (PE)   • Left ventricular thrombus 11. Thyrotoxicosis (reported in some studies) 12. Cardiac amyloidosis For more infographics: drmusmanjaved.com

Standard ECG calibration refers to the fixed paper speed and voltage gain used to record electrocardiograms, allowing accurate measurement and universal interpretation of ECG waveforms across patients, machines, and settings. STANDARD ECG SETTINGS Paper speed The standard ECG paper speed is 25 mm/second. At this speed: • 1 small square (1 mm) = 0.04 seconds (40 ms) • 1 large square (5 mm) = 0.20 seconds (200 ms) • 25 mm (5 large squares) = 1 second Some situations use alternative speeds: • 50 mm/second – improves visualization of tachyarrhythmias, flutter waves, or pacing spikes • 12.5 mm/second – rarely used, mainly for long rhythm strips Voltage (Amplitude) calibration Standard ECG gain is 10 mm/mV. At this calibration: • 1 mV electrical activity produces a vertical deflection of 10 mm • 1 small square (1 mm) = 0.1 mV • 1 large square (5 mm) = 0.5 mV This applies to both limb and chest leads unless otherwise stated. Calibration signal At the beginning of an ECG tracing, a calibration...

Modified European Heart Rhythm Association symptom scale for AF.

Left Ventricular Hypertrophy (LVH) on ECG: Diagnostic Criteria Explained Left ventricular hypertrophy refers to an increase in left ventricular muscle mass, most commonly due to chronic pressure overload such as long-standing hypertension or aortic stenosis. Although echocardiography is the gold standard for diagnosis, the ECG remains a widely used, inexpensive, and readily available screening tool. Several ECG criteria have been developed to identify LVH, each with its own strengths and limitations. Why ECG Criteria Matter ECG criteria for LVH are highly specific but relatively insensitive. This means that when criteria are met, LVH is likely present, but a normal ECG does not exclude LVH. ECG-detected LVH is clinically important because it independently predicts cardiovascular morbidity and mortality, including heart failure, arrhythmias, stroke, and sudden cardiac death. Sokolow–Lyon Criteria The Sokolow–Lyon criteria are among the oldest and most commonly taught ECG criteria for LV...

  Narrow Complex Tachycardia: ECG-Based Diagnostic Approach Narrow complex tachycardia (NCT) refers to a tachyarrhythmia with a heart rate >100 bpm and a QRS duration <120 ms. A narrow QRS indicates that ventricular activation occurs via the normal His–Purkinje system, implying a supraventricular origin of the rhythm. Systematic ECG analysis allows rapid and accurate diagnosis, which is crucial for appropriate management. --- Definition and ECG Criteria • Heart rate >100 beats per minute • QRS duration <120 ms • Usually supraventricular in origin --- Step 1: Assess Rhythm Regularity The first and most important step is to determine whether the rhythm is regular or irregular. --- Regular Narrow Complex Tachycardia Common causes include: 1. Sinus tachycardia • Gradual onset and offset • Normal P waves preceding each QRS • PR interval constant 2. Atrial flutter with regular block (e.g., 2:1 block) • Ventricular rate often ~150 bpm • Flutter waves may be hidden 3. AVNRT (At...

Ankle–Brachial Pressure Index (ABPI) Definition Ankle–Brachial Pressure Index (ABPI), also called Ankle–Brachial Index (ABI), is a simple, non-invasive bedside test that compares systolic blood pressure at the ankle with systolic blood pressure at the brachial artery to assess lower-limb arterial perfusion. --- Principle Peripheral arterial disease (PAD) causes reduced systolic pressure distal to arterial stenosis or occlusion. Comparing ankle pressure with arm pressure provides an objective estimate of arterial flow to the legs. --- Formula ABPI = Highest ankle systolic pressure (dorsalis pedis or posterior tibial) ÷ Highest brachial systolic pressure Measured separately for each leg. --- Methods of Measuring ABPI 1. Doppler-Assisted ABPI (Gold Standard) Equipment Hand-held Doppler (8–10 MHz) Sphygmomanometer cuffs (appropriate size) Steps 1. Patient rests supine for ≥10 minutes 2. Measure systolic BP in both brachial arteries using Doppler 3. Measure systolic BP at: Dorsalis pedis ar...