Fondaparinux is a synthetic pentasaccharide that exerts its anticoagulant effect by binding to antithrombin III, inducing a conformational change that selectively inhibits activated factor X (Xa). Unlike unfractionated heparin or low molecular weight heparins, fondaparinux does not inhibit thrombin (factor IIa) and is too small to promote platelet activation, making the risk…
Spontaneous coronary artery dissection (SCAD) is typically due to either a tear in the coronary artery’s intimal layer leading to blood propagation into the media layer and the creation of two distinct lumens (true and false) compromising blood flow to the myocardium. SCAD accounts for only 0.5-1% of acute coronary…
The WATCHMAN FLX™ Pro left atrial appendage (LAA) closure device is implanted percutaneously via the femoral vein → right atrium → a transseptal puncture → left atrium pathway to seal the LAA – a small pouch in the left heart where blood clots can form and potentially lead to strokes…
The left ventricle’s (LV) pressure-volume (P-V) loop visually represents an important relationship between the chamber’s pressure and volume over a single cardiac cycle. In the following diagram, systole is red, and diastole is blue. The P-V loop consists of four events:
Isosorbide mononitrate (Imdur, ISMN) and isosorbide dinitrate (Isordil, ISDN) are two nitrates used to induce venodilation and alleviate angina pectoris, but they differ in their pharmacokinetics and clinical applications. Both ISMN and ISDN are prodrugs that undergo biotransformation to release nitric oxide (NO). This occurs more directly in ISMN, whereas…
Understanding abnormal arterial waveforms is crucial in diagnosing various cardiovascular conditions. These waveforms, visualized through arterial pressure tracings, provide insight into the mechanical performance of the heart and the vascular system. Here are some common abnormal arterial waveforms: Pulsus bisferiens has two distinct systolic peaks (or the second in early…
2° atrioventricular block – Mobitz I (often referred to as the Wenckebach phenomenon) is characterized by the progressive lengthening of the PR interval with each successive heartbeat until a beat is completely blocked (a P wave not followed by a QRS complex). Mobitz I generally involves progressive fatigue of AV…
Double sequential external defibrillation (DSED) can be used in ventricular fibrillation (VF) which remains refractory to conventional ACLS protocols. It involves utilizing two defibrillators to rapidly deliver two shocks in succession to increase energy sent to the myocardium with multiple vectors at a lower shock impedance. This technique has also…
Unilateral cardiogenic pulmonary edema (CPE) accounts for ~2% of pulmonary edema cases and is classically caused by posterior papillary muscle rupture, resulting in acute, severe, eccentric mitral regurgitation. Flow is directed specifically to the right-sided pulmonary veins. This, in turn, overwhelms the lymphatic capacity of the right lung and results…
The right ventricle (RV) is designed to be a compliant volume chamber that pumps against a low-pressure, low-resistance pulmonary arterial (PA) system. RV-PA coupling refers to the proportional alignment between RV contractility and afterload. In situations of increased RV afterload like pulmonary hypertension, the RV can adapt (e.g., anatomic remodeling…