Echocardiogram vs. EKG – A CARE Guide About Uses & Differences

What Is an EKG (ECG or Electrocardiogram)?

The EKG is the most common diagnostic tool that measures and records the electrical activity of the heart – your heartbeats and heart rhythm. An EKG captures these electrical signals as waveforms on graph paper or a digital system for analysis. This allows the cardiologist or healthcare provider to look for any irregularities and to assess your heart health. [1]

If you wonder why EKG is sometimes written with K and other times with C, there is a simple explanation for that. The abbreviation EKG refers to the original German spelling “Elektrokardiogramm” while ECG literally stands for the English translation “electrocardiogram”.

How Does an EKG Work & What Does It Do?

Did you know that the human body works on bioelectricity? An EKG works by attaching electrodes to specific points on your body, typically on the chest, arms, and legs, to detect the electrical signals produced by your heart as it beats. These signals are then recorded and displayed as a waveform, allowing doctors to analyze the rhythm, strength, and timing of each heartbeat. [1]

1. Electrical Activity of the Heart: Your heart is not just a muscle; it's a complex electrical system. Each heartbeat is triggered by electrical impulses that originate in a part of your heart called the sinoatrial node (SA node). These impulses travel through the heart, causing the heart muscle to contract and pump blood.
2. Recording Electrical Signals: An EKG translates these electrical impulses into a graph. This is achieved by placing electrodes (small, sticky patches) on the skin of your chest, arms, and legs. These electrodes detect the tiny electrical changes on the skin that arise from the heart muscle's electrophysiologic pattern of depolarizing during each heartbeat.
3. Graphical Representation: The electrical impulses are displayed as waves on a paper or a screen. An EKG produces a series of waves and complexes, like the P wave (representing atrial depolarization), the QRS complex (ventricular depolarization), and the T wave (ventricular repolarization). [1]
4. Analysis of Heart Rhythm: By analyzing these waves, healthcare professionals can determine the rhythm of your heart, whether it's regular or irregular. They can also tell the speed of your heart rate and whether it’s normal, too fast (tachycardia), or too slow (bradycardia). [1]
5. Diagnosis of Heart Conditions: EKGs are crucial in diagnosing various heart conditions. For example, they can indicate a myocardial infarction (heart attack) by showing changes in the ST segment or the presence of Q waves. They can also detect heart enlargement, previous heart attacks, and issues with your heart's conduction system (a network of cells and electrical signals that control your heartbeat). [1]

Different Types of EKGs

• Standard (Resting) EKG: The Standard Resting EKG is the most common type. It records the heart's electrical activity while you are at rest, usually for a few minutes. It's used for detecting heart rhythm problems, heart attacks, and other heart issues and to assess your general heart health.
• Holter Monitor (Ambulatory EKG): The Holter Monitor is a portable device worn for a day or more to continuously record the heart's activity during your regular daily activities. It's useful for detecting heart rhythm irregularities that might not show up during a standard EKG.
• Event Monitor: Similar to a Holter monitor, this smaller device is used for longer-term monitoring, up to several weeks. In contrast to the Holter monitor, the event monitor does not record continuously, rather than being activated by you when feel symptoms. It's helpful for diagnosing intermittent arrhythmias or in analyzing your specific symptoms. [2]
• Stress Test (Exercise EKG): The exercise EKG monitors your heart while you exercise, usually on a treadmill or stationary bike. It helps to determine how well your heart handles physical activity and can uncover heart problems that are not evident when your heart is at rest.
• Signal-Averaged EKG: The signal-averaged EKG is a more detailed type of EKG used to detect subtle abnormalities in heart rhythm that could indicate an increased risk of heart rhythm disorders. It's often used in people who've had a heart attack or have other heart conditions.

What Is an Echocardiogram?

An echocardiogram (“echocardiography”) is another diagnostic tool that creates an ultrasound scan of your heart by using high-frequency sound waves (above the threshold of human hearing) to paint a moving and multidimensional picture of your heart. The echocardiogram provides information on the structure and function of your heart. [3]

How Does an Echocardiogram Work & What Does It Do?

In an echocardiogram, you will wear a special robe and usually lie on your left-hand side while ultrasound waves are directed toward your heart using a transducer that is moved over your chest. The transducer is a device that both emits and receives the sound waves. Using this imaging technique, cardiologists are able to thoroughly assess the entire structure and function of your heart, enabling them to anticipate potential heart issues and assess your heart health. [3]

1. Sound Wave Emission and Echo Detection: The transducer emits sound waves that travel through your body's tissues and fluids. When these waves encounter boundaries between different types of tissues, such as those between blood and heart muscle, they are reflected back to the transducer. This process is known as echolocation.
2. Image Creation: The time it takes for the echoes to return and their amplitude (strength) are processed by a computer. This data is used to construct real-time images of your heart's structures. These images are displayed on a monitor and can be recorded for further analysis. [3]
3. Heart Examination: The echocardiogram provides detailed information about your heart's structure and function. It can assess the size of your heart chambers, the thickness and motion of your heart walls, the functioning of your heart valves, and the direction and speed of your blood flow. It can also identify abnormalities like congenital heart defects, myocardial damage, and pericardial diseases. [3]

Different Types of Echocardiograms

There exist various types of echocardiograms, each tailored for specific diagnostic needs.

• Transthoracic Echocardiogram (TTE): The TTE is the most common type of echocardiogram. A transducer is moved over your chest, with ultrasound gel applied to it, to create images of your heart. The transthoracic echocardiogram is non-invasive, not painful and used for general heart examinations. Some advanced TTEs can also provide three-dimensional images of your heart, aiding in the assessment of heart valves and chambers. [3]

• Transesophageal Echocardiogram (TEE): In this type, a small transducer is guided down your esophagus, which is closer to the heart. This technique provides more detailed images, especially useful for examining heart valve function.

• Stress Echocardiogram: The stress echocardiogram is done before and after your heart is stressed, either through exercise or medication. It helps to assess how well your heart functions under stress which is useful in detecting coronary artery disease. [3]

• Doppler Echocardiogram: The Doppler technique focuses on blood movement through your heart and major blood vessels. It measures the speed and direction of blood flow, helping to identify abnormalities in blood flow patterns such as blood clots.

What Is the Difference Between an Echocardiogram and an EKG?

Both the echocardiogram and EKG are common non-invasive heart tests in cardiology used to paint a picture of your heart health, but they focus on different aspects. An echocardiogram uses ultrasound technology to create images of your heart's structure and motion, providing a visual assessment of the heart's size, shape, and pumping ability. [3]

In contrast, an EKG records the electrical activity of your heart, translating it into waveform lines that help detect heart rhythm and potential heart rate issues, as well as electrical conduction problems. [1]

While an echocardiogram is excellent for evaluating the physical and functional aspects of the heart, an EKG is key for analyzing the heart's electrical system and rhythm disorders. [1] [3]

Most cardiologists decide to use both tests in conjunction since they are complementary to each other. Together, these heart tests allow for a comprehensive insight into your heart health.

When Are Echocardiogram and EKG Tests Used?

Echocardiograms and EKGs are used in different clinical scenarios to diagnose and monitor various heart conditions or to assess heart health in general:

When Is An EKG Ordered?

The EKG is the most commonly ordered heart test to assess the electrical activity of the heart, and it is also used in more specific medical scenarios, listed below:

• Monitoring Heart Health: As a preventative measure, especially in patients with existing heart conditions, like after a heart attack or with implanted devices like pacemakers.
• Chest Pain or Heart Attack: To diagnose a heart attack or other forms of heart disease that can cause chest pain or discomfort.
• Arrhythmias: To detect irregular heartbeats, like atrial fibrillation or flutter.
• Pre-surgery Evaluation: As part of a routine checkup before surgical procedures.
• Evaluating the Effectiveness of Certain Heart Medications: To see how medicines are affecting heart rhythm. [1]

When Is An Echocardiogram Ordered?

Echocardiograms are typically used when there's a specific need to assess the structure and function of the heart visually.

They are particularly helpful in medical cases like:

• Damage After a Heart Attack: To evaluate areas of the heart that may have been damaged after a cardiac event.
• Cardiac Function: To assess the heart's pumping function, particularly in cases of heart failure or cardiomyopathy.
• Heart Murmurs: To evaluate abnormal heart sounds and determine their cause.
• Heart Valve Issues: To check for problems like valve stenosis (narrowing) or regurgitation (leaking).
• Congenital Heart Disease: To diagnose congenital disabilities in the heart's structure. [3]