The Cardiac Survivor Glossary

This glossary is a living document. I add to it as I learn. Last updated: September 2026.

I'm not a doctor. These definitions reflect my personal understanding as a cardiac survivor who has spent five years researching his own recovery. Always discuss your specific numbers with your physician.

If there's a term you've heard that isn't here — reply to any newsletter issue and ask. I'll add it.

ApoB (Apolipoprotein B)
The more accurate alternative to LDL. Every single LDL particle carries exactly one ApoB molecule — so ApoB gives you the actual particle count, not an estimate of cargo weight. Think of it this way: LDL counts the weight of the cargo. ApoB counts the number of trucks. Two people with identical LDL levels can have very different ApoB counts — and very different cardiac risk profiles.

Fasting insulin
The most direct measure of insulin resistance available. Reveals whether your body is responding to insulin appropriately — long before blood sugar or A1c becomes abnormal. Costs less than $20. Takes one tube of blood. Almost never ordered by cardiologists.

HbA1c (Glycated hemoglobin)
A measure of your average blood sugar over the past three months. Standard diabetes screening. Normal is below 5.7%. Pre-diabetes is 5.7–6.4%. Diabetes is 6.5% and above. A useful trend marker but a lagging indicator — it doesn't show what your blood sugar is doing after individual meals.

HDL cholesterol (High-Density Lipoprotein)
The number your doctor calls "good cholesterol." HDL particles travel through the bloodstream collecting excess cholesterol and transporting it back to the liver for disposal. Think of it as the cleanup crew. The higher your HDL, generally the better. Normal is above 40 mg/dL for men and above 50 mg/dL for women. Optimal is above 60 mg/dL. HDL is one half of the TG/HDL ratio — the most accessible proxy for insulin resistance available from a standard lipid panel.

hsCRP (High-sensitivity C-reactive protein)
A marker of systemic inflammation — the chronic fire inside the arteries that drives plaque formation. Normal is below 1.0 mg/L. Optimal is below 0.5 mg/L. Lower hsCRP means less arterial inflammation and less damage for particles like Lp(a) to attach to.

LDL cholesterol (Low-Density Lipoprotein)
The number your doctor checks every year, commonly called "bad cholesterol." Here's what most people don't know: LDL is not directly measured. It's calculated using a mathematical formula — the Friedewald equation — from your total cholesterol, HDL, and triglycerides. It's an estimate, not a count of actual particles. According to Harvard research, LDL has the lowest predictive value of all major cardiac risk factors. It's the number the system manages most — and the weakest signal of actual risk.

Lp(a) — Lipoprotein little-a
A genetically influenced lipoprotein that most cardiologists don't routinely test. Present in elevated levels in roughly 1 in 5 people. Far stickier than regular LDL — more likely to lodge in damaged arterial walls and trigger plaque formation. Major cardiology societies now recommend testing Lp(a) once in every adult. Only 1 in 1,000 adults has ever been tested.

TG/HDL ratio (Triglyceride to HDL ratio)
The most accessible proxy for insulin resistance available from a standard lipid panel. Divide your triglycerides by your HDL. A ratio above 2.0 is a warning. Above 3.0 is a red flag. Most doctors never calculate it — they look at LDL in isolation, which is the weakest predictor of cardiac events.

Coronary arteries
The blood vessels that supply oxygen to the heart muscle itself. Your heart pumps blood to your entire body — but it also needs its own blood supply to keep working. The coronary arteries are that supply line. When one gets blocked, the heart muscle it feeds starts dying. That's a heart attack.

Diastolic function
How well your heart relaxes and fills with blood between beats. Most people only hear about the squeeze (systolic function / ejection fraction). Diastolic function is the other half — and it's the form of heart failure most closely linked to metabolic disease. Grade I diastolic dysfunction means mild impairment of filling.

Ejection fraction (EF)
The percentage of blood your heart pumps out with each beat. Normal is 55–70%. A heart attack can damage the pumping muscle and reduce this number. EF measures the squeeze — how forcefully the heart contracts — but says nothing about how well the heart fills between beats.

Left ventricle (LV)
The main pumping chamber of your heart — the one doing the heaviest work, pushing blood out to your entire body with every beat. Most cardiac damage from a heart attack affects the left ventricle.

LV mass / LV mass index
The total weight of your left ventricle's muscle wall. When the heart works under chronic high blood pressure, the wall thickens to compensate — like any muscle responding to heavy work. This is called hypertrophy. Normal LV mass index for men is below 115 g/m². Borderline hypertrophy is 116–132 g/m².

Mitral valve / Mitral regurgitation
The mitral valve is the door between the upper and lower left chambers of your heart. Mitral regurgitation means the door doesn't close completely — blood leaks backward with each beat, making the heart work harder. Graded from trace (barely detectable) to severe.

Pericardial effusion
A small amount of fluid around the heart. A trivial pericardial effusion is a common finding and usually clinically insignificant. Worth monitoring at future scans to confirm it remains stable.

Pulmonary pressure (RVSP)
The pressure inside the blood vessels connecting your heart to your lungs. When a valve leaks backward, blood backs up and raises pressure in the lungs. Normal pulmonary pressure is below 35 mmHg.

Ramus intermedius
A fourth coronary artery present in roughly 1 in 5 people. Most people never know they have it. It supplies blood to a portion of the heart wall that would otherwise be served by branches of the left anterior descending or circumflex arteries. Clinically significant in the event of a heart attack affecting those territories.

Regional wall motion abnormality
An area of the heart wall that moves differently from the rest — usually because it was damaged by a heart attack and replaced by scar tissue. Described as hypokinetic (moves less than normal) or akinetic (does not move at all). Permanent findings from a heart attack do not reverse.

TAPSE (Tricuspid Annular Plane Systolic Excursion)
A measurement of how well your right ventricle — the heart's pump to the lungs — is contracting. Normal is 1.8 cm or above. Below 1.6 cm indicates impaired right ventricular function.

Aspirin
A blood thinner that reduces the ability of platelets to clump together and form clots. For post-heart attack and post-stent patients, aspirin is part of standard care — typically alongside a second antiplatelet medication for a period after the event. For people who have never had a cardiac event, current guidelines no longer recommend daily aspirin for most people — the bleeding risk outweighs the cardiac benefit. If you've had a cardiac event and are taking aspirin, do not stop without discussing it with your cardiologist.

Beta blocker (Carvedilol / Coreg)
A class of drugs that slows the heart rate and reduces blood pressure by blocking adrenaline. Commonly prescribed after heart attacks to reduce strain on the heart and manage arrhythmia. Also used in heart failure to improve long-term outcomes. If prescribed, do not stop taking without discussing it with your cardiologist.

Ezetimibe (Zetia)
A cholesterol-lowering medication that reduces the absorption of cholesterol from food in the small intestine. Works differently from statins, which reduce the liver's production of cholesterol. Often prescribed alongside a statin when LDL targets aren't reached with a statin alone, or as an alternative for patients who experience statin side effects. Primarily addresses LDL — it does not directly target insulin resistance, inflammation, or Lp(a).

PCSK9 inhibitors (Repatha, Praluent)
A newer class of injectable medications that lower LDL cholesterol by 50–60% on top of statin therapy. They work by blocking a protein that normally breaks down LDL receptors in the liver — leaving more receptors available to clear LDL from the bloodstream. Some research suggests they also modestly reduce Lp(a) by 20–30%. Administered by injection every two to four weeks. Typically reserved for high-risk patients who can't reach LDL targets on statins alone. Cost is significant — often $5,000–$7,000 per year before insurance.

Prednisone
A corticosteroid — a powerful anti-inflammatory medication commonly prescribed for conditions ranging from allergic reactions and respiratory infections to autoimmune diseases and joint inflammation. It works by suppressing the immune system's inflammatory response. For cardiac survivors, prednisone carries specific risks worth knowing. It can elevate heart rate, raise blood pressure, cause fluid retention, and temporarily worsen insulin resistance — all of which place additional strain on a heart already managing post-MI recovery. Even a short course can produce measurable changes in heart rate and glucose levels in people with underlying cardiac vulnerability. If you are prescribed prednisone for any reason — even a brief course — inform your cardiologist.

Statin
A class of drugs that lowers LDL cholesterol by inhibiting an enzyme in the liver involved in cholesterol production. The most commonly prescribed cardiac medication. Statins have meaningful benefit for secondary prevention — preventing a second cardiac event in post-MI patients. Their benefit for primary prevention is more modest. Statins primarily address LDL — they do not directly target insulin resistance, inflammation, or Lp(a).

CGM (Continuous Glucose Monitor)
A small sensor worn on the arm that measures blood glucose levels in real time — every few minutes, around the clock. Shows what happens to your blood sugar after every meal, during exercise, and while you sleep. Reveals patterns that annual bloodwork and even HbA1c cannot capture.

Insulin resistance
When your cells stop responding to insulin efficiently. The pancreas compensates by producing more. Over time, chronically elevated insulin inflames arterial walls, raises blood pressure, promotes visceral fat accumulation, and creates the metabolic environment in which plaque builds. According to Harvard research, insulin resistance is six times more predictive of cardiac events than LDL cholesterol.

Metabolic syndrome
A cluster of conditions that occur together and significantly increase cardiac risk: elevated blood pressure, high blood sugar, excess abdominal fat, and abnormal cholesterol or triglycerides. Having three or more of these meets the diagnostic criteria. Carries a six-fold increased risk of cardiac events according to Harvard research.

TOFI — Thin Outside, Fat Inside
A person who appears to be at a healthy weight but carries significant visceral fat around their organs. Normal BMI. Normal body weight. Metabolic damage accumulating invisibly — including insulin resistance, arterial inflammation, and building plaque. A normal weight tells you nothing about what's happening inside.

Visceral fat
Fat stored around your internal organs — liver, pancreas, intestines — rather than under the skin. Unlike subcutaneous fat (the kind you can pinch), visceral fat is metabolically active. It produces inflammatory signals that damage arterial walls and worsen insulin resistance. BMI and body weight do not measure visceral fat.

CAC scan (Coronary Artery Calcium scan)
A direct imaging of calcified plaque in your coronary arteries. Not a proxy. Not a prediction. The actual problem — visible on a scan. Costs roughly $100–$150. Takes about 10 minutes. Gives you a score that tells you precisely how much arterial plaque burden you're carrying. Most cardiologists never order it.

ECHO (Echocardiogram)
An ultrasound of the heart. Shows the structure and function of the heart in real time — valve function, wall motion, ejection fraction, chamber size, and pressure measurements. The most comprehensive non-invasive cardiac imaging test available in routine care.

Holter monitor
A portable device worn for 7–14 days that continuously records your heart's electrical activity. Captures arrhythmias that might be missed in a standard ECG taken during a brief office visit.

NSVT (Non-Sustained Ventricular Tachycardia)
A rapid heart rhythm originating in the ventricles — the lower chambers of the heart — that starts and stops on its own within 30 seconds. Considered non-sustained because it terminates spontaneously. Worth investigating in post-MI patients to determine the underlying cause.

Sleep study (Polysomnography)
An overnight test that monitors brain activity, eye movement, heart rate, breathing, and oxygen levels during sleep. Used to diagnose sleep apnea and other sleep disorders. Relevant for cardiac survivors because untreated sleep apnea increases sympathetic nervous system activity, raises resting heart rate, worsens insulin resistance, and is associated with increased cardiac risk.

If you heard a term in a cardiology appointment, in the webinar, or in a newsletter issue that isn't defined here — reply to any newsletter issue and ask. I'll add it to the next update of this glossary.

This glossary reflects Dennis Isip's personal understanding as a cardiac survivor and is not medical advice. Always consult your physician or cardiologist regarding your specific situation.

— Dennis
Cardiac Survivor · Your Friend in Recovery
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