Dictionary

May your heart find its way through the maze of terminology. Use this dictionary to help guide you!

Term	Description
ACS / Acute coronary syndrome	Acute event that results from the rupture of an atherosclerotic plaque and the formation of a blood clot (thrombus) within a coronary artery, leading to a sudden reduction in blood flow. ACS includes conditions like unstable angina, NSTEMI, and STEMI. ACS is a complication of CAD (which is a chronic condition).
Adenosine	Induce transient hyperemia (short term increased blood flow) by causing coronary vasodilation. It mimics the effects of exercise or stress on the heart. Always used in FFR and IMR. In FFR, it maximises blood flow in the arteries, allowing accurate measurement of pressure differences across a lesion and determining the significance of coronary stenosis.
Air Kerma	Kinetic energy released per unit mass. Quantifies the energy transferred from the X-rays to the air particles
Angioplasty	Using a balloon to stretch open a narrowed artery. Typically involves stenting as well, which is a type of angioplasty.
Aramine	Vasopressor used to increase blood pressure when a patient experiences hypotension (low blood pressure). This effect is crucial in maintaining adequate perfusion, especially in patients whose blood pressure may drop during or after sedative administration.
Balloon Brushing	Technique where a balloon catheter is inflated in a narrowed or occluded coronary artery and then gently "brushed" or moved back and forth. The goal is to dislodge some of the plaque, helping to create a clearer path for guidewires.
Balloon Pump	A balloon catheter which is place in the descending aorta to increase blood flow, usually insterted when a patient had heart attack, heart failure, cardiogenic shock or before/after a major surgery. It is timed to inflate during the heart's relaxation phase, which helps push blood forward to the body, and deflate during the heart's contraction phase, allowing blood to flow back into the heart more easily - triggered by the ECG. May remain for a few days, all the while the patient must remain supine.
Beta Blocker	Used to optimize patients with stable angina, ACS and hypertensive by reducing oxygen demand and controlling heart rate. Results in negative chronotropic (slow heart rate down) and inotropic effects (decreases the force of myocardial contraction). This results in less motion artefact from pts with tacchychardia.
BMW / Balance Middle Weight	Type of guidewire that has a flexible core (can be turned with a torquer device), a hydrophilic coating (provides lubricity), and a soft tip that can be bent to prevent perforation.
Cardioversion	Procedure used to restore a normal heart rhythm in pts with arrhythmias, such as AF, atrial flutter, or supraventricular tachycardia (SVT). It can be performed electrically or chemically (with medications)! Cardioversion is synchronised whereas defibrillation is unsynchronized and used for life-threatening arrhythmias (e.g., ventricular fibrillation, pulseless VT). May be used before ablation since a normal rhythm is necessary to properly map the hearts electrical activity or to safely position catheters, as well as after ablating to confirm the effectiveness of the ablation.
CRTD / Cardiac Resynchronization Therapy Defibrillator	Combines cardiac resynchronisation with an ICD. The CRT is essentially a biventricular pacemaker - delivers biventricular pacing to synchronize the contractions of the left and right ventricles. The ICD monitors the heart for life-threatening arrhythmias, such as VF, and delivers electric shocks to restore a normal rhythm.
CTO / Chronic Total Occlusion	The vessel has been totally occluded over a long period of time (resulting in hard plaque or fibrotic tissue) making it very difficult to stent. May require use of rotablation, and typically 2 access points (radial and femoral artery) are used to wire the artery from both ends. Distally, collateral connections are accessed to create a retrograde path through the occlusion.
Damping	Pressure measured from the tip is 'damp' (inaccurate/changed waveform) because the catheter tip is not free, there is an air bubble or a clot in the system. Important to let the cardiologist know so they can readjust the catheter position or flush the catheter. When accessing the RCA, the conus artery may accidentally be engaged. This is particularly dangerous since the conus artery supplies the right ventricular outflow tract (RVOT), which is closely associated with the conduction system of the heart specifically the His-Purkinje system. If contrast is injected it may cause ischaemia and STEMI!
DAP / Dose area product	Area multiplied by air kerma. Relevant to stochastic effects.
DEB / Drug eluting balloon or DCB / Drug coating balloon	As per a normal stent, pre-dilation is required. The balloon is then inflated, releasing the drug rapidly to prevent it from being washed away in the bloodstream (dr may ask for a timer!). It inhibits smooth muscle growth and prevents the artery from narrowing again. DEBs are particularly useful for in-stent restenosis and small vessel disease. It releases what is essentially an immunosuppressent to prevent the own body from 'rejecting' the stent and prevent clot formation/restenosis!
Deterministic effects	Has a clear threshold, higher dose = greater severity and observable tissue effects (skin redness, burns, hair loss etc,)
DFR / Diastolic flow ratio	Similar to FFR, DFR measures coronary pressure to assess stenosis severity; however, it is performed at rest, without the need for adenosine or hyperemia induced. Unlike FFR, which evaluates pressure across the entire cardiac cycle, DFR is measured only during diastole, when resting flow rate is most stable.
Dual antiplatelet therapy	Combined use of two antiplatelet medications to reduce the risk of blood clot (thrombus) formation. Typically aspirin and P2Y12 Inhibitor. Aspirin prevents aggregation/chaining of RBC. Especially important for patients to comply to DAPT after stenting! (Compliance may effect decision of stenting vs DEB)
Ectopic	Abnormal electrical impulse that originates outside the normal conduction pathway of the heart. These impulses cause premature or extra heartbeats, disrupting the normal rhythm.
EDP / End diastolic pressure	Refers to the pressure within a heart chamber (ventricle or atrium) at the end of diastole, just before the heart contracts during systole; pressure when the heart is filled with blood to its maximum volume. LVEDP is often clinically significant as it reflects left ventricular preload and helps assess left heart function. Elevated LVEDP indiacts heart failure (measured via PAWP)
FFR / Fractional Flow Reserve	Provides quantitative measurement of severity of stenosis, pressure of artery and aids in stent choice. Calculated by obtaining the proximal aortic pressure (Pa) and distal coronary pressure (Pd) during maximum hyperaemia. Hyperemia (induced by adenosine) ensures that the resistance in small vessels remains constant, making the pressure ratio a true reflection of stenosis severity. If there is a gradient FFR ≤ 0.80 then the lesion is significant enough to stent.
Filter catheter	A catheter with a 'bucket' at the end made of a self-expanding mesh fibre allowing blood to flow through but catching thrombi or atheromatous plaques during intervention. Prevents emboli from traveling to smaller vessels and causing ischemia (e.g., stroke or distal tissue damage). Commonly used for vein graft stenting which has a high risk of embolisation, a filter catheter is advanced and deployed distal to the lesion in the vein graft.
GTN / Glyceryl Trinitrate	Vasodilator, used to distinguish true vessel narrowing due to disease from a temporary vasospasm. If the artery widens after GTN administration, it suggests the narrowing was likely due to spasm, not a permanent lesion.
Heparin	Anticoagulant which reduces chance of thrombosis/blood clot during procedure whilst inserting equipment into arteries. Inhibits clotting factors like thrombin and factor Xa. Administered amount depends on patient weight.
ICD / Implantable Cardioverter Defibrillator	For patients with rapid heart rhythms (tacchychardia) that could lead to cardiac arrest/VF. Can act as a PPM, but can additionally deliver much higher-energy electrical shocks to restore normal rhythm.
IMR / Index of Microcirculatory Resistance	Characterises coronary microvascular dysfunction by estimating coronary blood flow and microcirculatory resistance. Performed when pt has angina/indicative symptoms but no clear signs of large vessel disease. Product of distal coronary pressure and mean transit time of saline boluses. IMR of < 25 is normal
IVL / Intravascular lithotripsy.	Technique that uses acoustic pressure waves (shockwaves) to fracture deep calcium deposits within the artery wall. Compared to rotablation, it has a shallow learning curve, is easier to use and lower probability of complications (e.g. perforation/restenosis). Read more about it here
IVUS / Intravascular Ultrasound	A unique catheter with US probe on the end is placed at the site of stenosis. Imaging is used to quantify vessel lumen and wall diameter to characterise lesion/plaque and ultimately guide stent sizing/length.
JL / Judkins Left or JR / Judkins Right	Flexible catheters that curve 'J' for easier access to their respective arteries, allowing for easier engagement and manipulation to reach the ostiums. A smaller JR size (e.g. JR 4) may be chosen for diagnostic examinations whilst a larger size (JR 6) may be used if ballooning/stenting. Other factors for size choice include body size, vascular health or access site (radial vs femoral). Named after Melvin Judkins who was an American physician that pioneered interventional radiology techniques and equipment, including invention of pre-shaped catheters.
LAA / left atrial appendance	A small, ear-shaped pouch extending from the LA of the heart. It plays a role in atrial contraction and blood storage but is also a common site for blood clot formation, especially in patients with atrial fibrillation (AF). Clots from the LAA can enter the bloodstream and increase the risk of stroke.
LAD / Left anterior descending a.	Supplies the anterior portion of the left ventricle and anterior ventricular septum!
Manifold	A multi-port device used to control and direct the flow of fluids, such as contrast media, saline, and heparin, while also allowing for pressure monitoring during interventional procedures. A manifold typically consists of 3-5 ports, each controlled by a stopcock (a rotating valve) that can open, close, or divert flow between different fluid lines. It's purpose is for efficient fluid management, minimise contamination and air embolisms, ensure accurate delivery of contrast and pressure readings. The thing on the end of every bed that the nurses 'tap' air out of.
Midazolam	Sedative and anxiolytic (anti-anxiety medication) commonly used to help patients feel relaxed and comfortable during procedures.
MLA / minimal luminal area	The smallest cross-sectional area within a coronary artery at a site of stenosis, as measured by IVUS or OCT. For the LMCA, MLA <6.0 mm² is significant and likely require PCI. For all other vessels, MLA <4.0 mm² is significant.
NC / Non-compliant	Referring to the balloon type. Non-compliant balloons are used post-stenting to appose the stent to the vessel wall. May also be used pre-stenting depending on plaque characteristics.
Nominal	The manufacturer-recommended inflation pressure at which a balloon catheter fully expands to its intended/labelled size. NC (non-compliant) balloons maintain their size even at higher pressures, whereas semi-compliant balloons may expand slightly beyond nominal size.
NSTEMI / Non-ST elevated myocardial infarction	A less severe type of heart attack, with only partial blockage of the artery (or blockage in a small artery) and thus a small portion of the myocardium dying. The pt will typically experience less pain compared to a STEMI, and not as likely to go into VF. Treatment is more conservative (i.e. may not stent) and not as time critical.
OCT / Optical coherence tomography	Captures intra-luminal imaging - contrast is injected to fill the vessel, while pulling back the catheter and obtaining the image (the contrast replaces the blood to get an accurate representation of the interior of the vessel). Performed pre-stenting to obtain information on morphology or occlusion, length and diameter of stent. Performed post-stenting to check apposition (adherence to vessel wall) and positioning of stent
PAWD / PA wedge pressure or PCWP / Pulmonary Capillary Wedge Pressure	Pressure within the pulmonary arteries when a balloon-tipped catheter is wedged into a small/distal branch, essentially blocking blood flow. It reflects the filling pressure in the left atrium. Increased pressure indicates heart failure, mitral stenosis, or myocardial infarction.
PDA / Posterior Descending a.	Supplies the inferior wall of the left ventricle and interventricular septum.
Pericardiocentesis	Pericardial tap - procedure to aspirate/remove fluid from the pericardium. Using echo guidance, excess pericardial fluid is removed from the pericardial sac. When the pressure of the fluid exceeds the pressure in the heart, the pressure within the heart is reduced and less blood is able to be pumped out.
PLV / Posterior Left Ventricular a.	Supplies the posterolateral wall of the left ventricle.
PPM / Pacemaker	For patients with slow heart rate (bardycardia) Delivers small, low-energy electrical impulses to maintain or regulate the heart rate. Made of 2 components - pulse generator and leads. Leads inserted via the subclavian vein, with the lead tips situated in either the RV and/or RA. Uses electrical impulses to correct irregular heartbeats.
PSD / Peak Skin Dose	Highest dose to the imaged area. Relevant to deterministic effects/tissue retention, taking into account the back scatter and overlapping projections.
Pullback	A pressure wire is inserted into the artery, and as the catheter is pulled back, it continuously measures the pressure at different locations, helping to determine if a lesion is functionally significant and if it affects blood flow. Typically performed at the end of a LHC to measure the pressure differences between the LV and aorta for aortic valve stenosis.
Ramus	Artery that comes off the left main. If it branches off from the LCx, it is named an OM instead.
Rotablation	Rotational Atherectomy (Rotablation) uses a diamond-tipped burr that rotates at a fixed high speed (140,000–180,000 RPM) to break down heavily calcified plaque (e.g. in CTO). It grinds the hard plaque into microscopic particles that are safely absorbed by the body. Orbital rotablation is an advanced technique that uses an eccentric diamond-coated crown that moves in an orbital motion around the artery, increasing contact area while allowing blood flow during the procedure.
Shockwave	Shockwave is the brand name of the IVL system, developed by Shockwave Medical.
Sion Blue / Black	Types of guidewire which have excellent torque control and trackability. The Sion Blue has a softer tip, allowing it to be more forgiving when navigating through tight or angulated coronary arteries, chosen when precise navigation and high torque control are needed. The Sion Black has a stiffer tip and provides more support and stability to traverse stiff lesions or calcified plaques.
STEMI	ST-Elevation Myocardial Infarction. Complete blockage of a major artery, causing a spike in the ST segment in an ECG.
STENTBOOST	Setting used in post-dilation of stents to clearly visualise stent walls and apposition to vessel wall. A reference image of the vessel is used, and any motion is stabilized by the software. During post-processing, a frame-averaging algorithm to combine multiple frames into one and contrast enhancement algorithms to increase spatial resolution. Doctors will typically cone in themselves, and afterwards a reference image will automatically be saved (meaning if you have auto-reference button you might need to take it off!).
Stochastic effects	Random probability of occurring based on the dose but does not have a threshold. The higher the dose, the greater the likelihood of the effect, but its severity is not dose-dependent. Effects include cancer and genetic mutations.
SVT / Supraventricular tacchychardia	Rapid heartbeat involving an electrical pathway above the ventricles. Treated with SVT ablation.
Threatened STEMI	High risk of STEMI but not quite meeting all the criteria. For example, a transient ST evelation which returned to normal caused by temporary ischemia from a partially occluded coronary artery. May be ST-segment elevation in certain leads, but it might not be as widespread or as marked as in a full STEMI.
Thrombolysed STEMI	When thrombolytic therapy (also known as fibrinolysis) is used to dissolve the clot obstructing a coronary artery, restoring blood flow to the heart. Used when PCI is not available or feasible within the recommended time window, usually within 12 hours of symptom onset.
TOE / Trans-oesophageal echo	Ultrasound imaging technique that uses a probe inserted into the esophagus to obtain detailed images of the heart and blood vessels. In cathlab, it is used to guide procedures such as ASD/PFO closure (to assess defect size and ensure proper device placement), mitral valve interventions (e.g., MitraClip or balloon valvuloplasty for better valve visualization), left atrial appendage closure (to confirm anatomy and rule out thrombus), and TAVI (for assessing aortic valve sizing and deployment accuracy).
Trop / troponin	Protein found in the cells of your heart muscle. Without oxygen from blood, heart muscle cells die and release troponin (thus higher levels = indicator of heart attack). Troponin I is only found in the heart muscle, while troponin T is found in the heart muscle and other muscles. Troponin levels usually increase sharply within 3-12 hours after a heart attack and peak about 24 hours after the heart attack before taking several days to return to normal.
Verapamil	Always used prior to radial access- reduces vasospasms making it easier to access/wire. It is a calcium channel blocker that inhibits the influx of calcium ions into cardiac and smooth muscle cells, leading to relaxation of blood vessels and reduced heart workload. Verapamil is especially effective as an anti-arrhythmic due to its ability to slow conduction through the AV node and suppress abnormal electrical activity in the heart.
VF / Ventricular Fibrillation	A life-threatening cardiac arrhythmia where the ventricles quiver instead of contracting effectively, preventing blood from being pumped to the body. It is typically the cause of sudden cardiac arrest and requires immediate defibrillation to restore a normal heart rhythm.
Warfarin	Anticoagulant that is orally taken and usually for long-term therapy as opposed to short-term like herpain. Requires INR (International Normalized Ratio) monitoring unlike aspirin. Specifically, it inhibits the synthesis of vitamin K-dependent clotting factors.
Watchmans	The Watchman device is a LAA closure device used to reduce the risk of stroke in patients with AF who are at high risk of clot formation but need an alternative to long-term anticoagulation. Over time, heart tissue grows over the device, permanently sealing off the LAA to prevent clot formation and embolization.