Heart Disease 101
Updated: Oct 7, 2021
A blog by our CMO, David Bragg, MD
Heart disease is a general term that primarily consists of four different disease states:
Coronary heart disease (CHD)- also called coronary artery disease (CAD) is the leading cause of death in the US. It accounts for over $219 billion in direct medical costs and lost productivity annually (2015, CDC data). Over 655,000 Americans die annually from CHD, or 1 person every 36 seconds. It’s a chronic condition that most commonly caused by decreased blood flow through the coronary arteries, resulting in diminished pumping capacity of the heart, especially with increased cardiac demands (physical exertion).
Heart Attack- the medical term is myocardial infarction (MI), or acute myocardial infarction (AMI). This occurs from a sudden blockage of blood flow in a coronary artery by a blood clot. Most MI’s are the result of CAD. There are approximately 1.5 million MI’s annually, of which 1 in 5 are “silent”, meaning the patient has little or no symptoms. One person has an MI approximately every 40 seconds in the US.
Arrhythmias- this is an irregular heart rhythm due to changes in the conduction of electrical impulses throughout the heart. The most common cause of arrhythmias is CAD, but can also be caused by heart muscle injury (physical, MI, heart surgery, other). The most common sustained arrhythmia is atrial fibrillation (A Fib, or AF). The most common arrhythmia is PVC’s (Premature Ventricular Contractions), which are mostly harmless and require no treatment. AF can be paroxysmal, persistent, or permanent. AF increases with age, The most important aspect of AF is determining its risk of causing thromboembolism-blood clots, esp. strokes, or Cardiovascular Accidents (CVA’s).
Heart failure (CHF)- Congestive Heart Failure (CHF) occurs when the heart muscle is unable to adequately pump blood throughout the heart arteries and the rest of the body. CHF can result from failure of the right side of the heart or left side of the heart. The etiologies for L and R sided CHF are different. Over 550,000 people are diagnosed with CHF each year, primarily occurring in people over age 65. The main causes of CHF are:
HTN (hypertension, or high blood pressure)
Conditions that overwork the heart like COPD (chronic obstructive pulmonary disease), kidney failure, especially ESRD (end stage renal disease), liver failure (cirrhosis, chronic hepatitis, other)
Congenital heart defects
Risk factors for heart disease are age, smoking, high cholesterol-especially high LDL and low HDL, sex (men > women), poor diet, HTN, family history (15% of MI’s due to genetics), and sedentary lifestyle.
Diagnostic testing- the most commonly used and useful tests are the following:
ECG (EKG)- can display arrhythmias, electrical conduction issues, ischemia (inadequate cardiac blood flow), MI’s (either acute or past), and other things. Important measurements of an ECG include waveforms, rhythms, heart rate, and analysis of electrical components (see QRST section below).
Traditional Holter monitoring- mostly 24 or 48 hour tests (occasionally 72 hour) using a 5 or 7 lead wired device. The monitor is usually about 50% larger than the Recobro. It detects irregular heart rhythms often not detected on a single resting ECG. They usually are able to detect waveforms, rhythms, and electrical irregularities (QRST analysis). Results are usually read anywhere from 1-7 days after monitoring completion and return of the device. It is typical to take 1-2 weeks for a patient to receive results from a traditional Holter monitor test. It is primarily used for arrhythmia detection, but can also detect electrical conduction defects and signs of ischemia. IHD (Ischemic Heart Disease) is important as it causes Angina (chest pain from inadequate cardiac blood flow) and/or MI. ECG patch monitoring (like LifeSignals) has been increasingly used over the last few years., although still comprise a minority off the extended cardiac market. They typically use 2 leads to capture the waveform, rhythm, and some QRST irregularities, depending on the device. Studies have clearly demonstrated that 7-10 day cardiac monitoring captures significantly more important events than does traditional 24-48 hour Holter monitors.
Stress testing- this is primarily used to detect CAD and exercise capacity/limitations. Stress testing can often detect CAD that’s not evident on a resting ECG. Stress testing can be done in multiple ways, including using a treadmill (most common). The standard protocol is using a Bruce protocol that increases both the speed and incline of the treadmill, trying to evoke a cardiac problem if it’s there. Stress testing can be done using injected nuclear medications in conjunction with echocardiograms that increase the sensitivity of the test.
Cardiac catheterization (cath)- this procedure injects a dye into the veins that are then circulated through the heart arteries to try to detect areas of blockage. If coronary artery blockage is found, then angioplasty (balloon expansion) with or without stents can often be performed to open up the blockage. Stents are basically permanent tubes placed in the area of blockage after the balloon has opened the blocked artery. Stents can be “drug eluding”, meaning they contain a drug designed into the stent that helps prevent re-closure of the artery. There are limitations to angioplasty depending on blockage size, location, accessibility, etc). If angioplasty cannot be performed due to different reasons, then CABG (Coronary Artery Bypass Grafting) or medication management is usually the alternative.
Imaging- Coronary CT scans are often used, along with echocardiograms and chest x-rays.
Blood tests- certain blood tests can be helpful in evaluating heart disease, such as BNP (B type Natriuretic Peptide) in helping diagnose and manage CHF.
Heart Disease and RPM
Managing cardiovascular disease (CVD) with remote patient monitoring (RPM) has shown significant improvement in patient outcomes. Data indicate that the use of RPM devices can lead to reductions in blood pressure, predict CHF decompensation, and detect arrhythmias early to enable faster interventions. RPM has also been shown to detect early indications of infection (such as Covid-19) using both temperature and RR (Respiratory Rate) monitors, worsening signs of COPD, and other disease states. There are multiple studies indicating overall cost reductions, improved patient outcomes, and increased patient satisfaction using RPM in most all of these conditions.