What Causes Abnormal ECG Results

An ECG is a non-invasive test that measures the heart's electrical activity. An abnormal ECG can mean many things. Often, an abnormality is a normal variation of the heart's rhythm and does not affect the heart's health.

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At other times, abnormal ECG signals indicate a medical emergency, such as a heart attack or a dangerous arrhythmia. Wearable devices and fitness trackers are recent technological developments that have made the detection of heart diseases possible earlier.

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This blog lists causes of abnormal ECGs and factors that cause abnormal results, ranging from heart rhythm irregularities to underlying medical conditions. At Gauze, we are committed to helping you understand the intricacies and causes of abnormal ECG results and their implications on our heart health.

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How Does an ECG Work?

An ECG machine is a portable machine with 12 leads attached to sticky electrodes. The electrodes are placed on the chest, around the heart, and on the arms and legs. They sense the electrical impulses coming from multiple directions. The heart conducts electricity in standard pathways from the right atrium to the left atrium.

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The electric current then flows to the atrioventricular node and signals the ventricles to contract. The current then flows to what is known as the bundle of His. Fibers from the bundle of His subdivision provide current to the left and right ventricles. Any disruption in this current affects the heart's ability to work well. ECG detects these disruptions in the electrical conduction.

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What is a Normal ECG Result?

Normal heart rate, rhythms, waveforms, and intervals help us to assess heart health. A healthy heart has a regular rhythm and rate. Normal patterns distinguish them from abnormal ones, leading to timely medical intervention. Each component plays a role in understanding how the heart functions and indicates underlying health issues.

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1. Heart rate is between 60 and 100 beats per minute in a healthy adult.

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2. Rhythm: Normal ECG rhythm is the Sinus rhythm.

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3. Waveform: The normal waveform has.

• P Wave is formed as a result of the electrical activity that causes the contraction of the atria, the upper chambers of the heart. 

• The QRS complex is formed by the electrical activity that causes the ventricles to contract.

• T Wave: represents ventricles returning to the resting state.

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4. Intervals are the duration of time taken by the electrical wave to travel from one wave segment to another.

• PR Interval is the time taken for the electrical signal to travel from the atria to the ventricles. Normal interval duration is 120 and 200 milliseconds.

• QT interval is the time taken by the ventricles to contract and relax.

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Symptoms Indicating you Need an ECG

Even when the heart is functioning normally, one may experience symptoms indicating that medical attention is required.

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They are:

• Chest pain or discomfort.

• Difficulty in breathing.

• Palpitations or feeling your heart is beating oddly.

• Racing heart.

• Fainting feeling.

• Sudden weakness.

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What Does an Abnormal ECG Indicate?

An abnormal ECG indicates that all is not as expected in the ECG reading. It may or may not be a sign of an unhealthy heart. For example, athletes have an unusually low heart rate. However, this is not because of a cardiac abnormality; rather, it is a functional adaptation. An abnormal ECG reading could appear for many reasons.

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Recognizing and understanding these features of abnormalities is important for the detection and treatment of heart-related conditions. Heart rate, rhythm, and waveform irregularities help us to take timely action and improve patient outcomes and heart health.

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Common indicators of abnormal ECG

Heart rate, rhythm, and waveforms are indicators of an abnormal ECG.

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1. Heart rate

A human heart beats 60 to 100 times per minute. If the number of these beats increases or decreases, the ECG detects it. Healthcare providers can then investigate the reason.

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2. Heart Rhythm

People notice the sensation of missing a beat, skipping a beat, or fluttering of the heart. These are changes in the rhythm that people experience. An ECG helps us detect how and when these changes in rhythm are occurring and whether they are significant. A 24X7 monitor, like a Holter monitor, helps healthcare professionals know about such rhythms.

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3. Abnormal waveforms

Abnormal waveforms on the ECG represent irregular electrical activity within the heart. Each wave, P wave, QRS complex, and T wave provides specific information about the heart's function. If any part of the waveform is changed, it suggests an abnormality.

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Causes of abnormal ECG results

The causes can be classified into: 

• Cardiac-related.

• Non-cardiac related.

• External.

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Cardiac related

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1. Arrhythmia

It refers to heart rhythms that make a heartbeat too fast, too slow, or even in uncoordinated patterns. A healthy heart beats 60 to 100 times per minute. A heart rate faster than 100 indicates tachycardia, whereas a rate slower than 40 beats a minute indicates bradycardia. In conditions like atrial fibrillation, the heart rate is over 100 beats.

2. Heart attack

In a heart attack, the heart does not get a fresh supply of blood, which causes damage to the tissues and even the death of cells. Damaged tissue and healthy tissue are then unable to conduct electricity, causing abnormal ECG readings. These readings also indicate if you have had a heart attack previously.

3. Ischemia

Whenever there is reduced blood flow to the heart muscles, ischemia occurs. Angina is a chest pain or discomfort that occurs when the heart muscles are not able to get oxygen-rich blood. It may be a brief event, and if it last longer, it can lead to a heart attack.

4. Cardiomyopathy

Our heart, which is the size of a fist, changes in size due to diseases like hypertension or high blood pressure, viral infections of cardiac muscles, advanced age, and heart failure. These conditions cause changes in the ECG waves.

Non-cardiac

1. Electrolyte imbalance

When electrolytes and minerals (potassium, calcium, and magnesium) become dysregulated in our body, the electrical activity of the heart is affected. An increase or decrease in their concentrations affects the ECG.

2. Lung condition

They cause changes in the ECG due to increased pressure in the chest. Though the ECG changes are non-specific, when they are seen in combination with clinical symptoms, they reveal underlying lung disease.

3. Thyroid diseases

Both hypo- and hyperthyroidism cause changes in the ECG. Hyperthyroidism causes an increase in heart rate, and hypothyroidism slows the heart rate. Treating the underlying thyroid condition normalizes the ECG.

4. Medication

Some medications alter the heart's electrical activity and cause changes in the ECG. Some medicines speed up the heart rate, while others slow it down. Medications that are used to balance the heart rhythm can also cause abnormal rhythms in some individuals. Anti-arrhythmics, antidepressants and Digoxin cause changes in the ECG pattern.

External

1. Stress 

Even when people have no underlying heart disease, emotional and physical stress can cause changes in the ECG. Stress releases hormones like adrenaline, which increase heart rate, blood pressure, and cardiac workload. Stress worsens it. The changes can be reversed if stress is removed.

2. Dehydration

Dehydration affects the heart's electrical activity mainly because of electrolyte imbalances. The imbalances disrupt. The normal conduction and repolarization of the heart. Extreme dehydration reduces heart perfusion and causes ischemia-like changes.

3. Body position

Body position causes a change in ECG readings due to the change in the heart's orientation within the chest. The position of the diaphragm and heart shifts, which affects the axis and the amplitude of ECG waves. These changes, however, are physiological and not a matter of concern. It just highlights the importance of standardizing patient position during ECG recordings.

4. Technical

Not all ECG abnormalities are due to heart problems. It can even be due to technical problems while doing an ECG. Poor electrode placement on the chest, loose or dry electrodes, improper skin preparation, and lead reversals are some of the important causes of abnormal ECG.     

Preventions and Precautions

Giving priority to leading a healthy life, adopting preventive measures not only helps to detect the underlying conditions but also aids in long-term wellness monitoring. Maintaining blood pressure and cholesterol levels, along with a healthy lifestyle, reduces the chances of developing heart conditions. Some steps we should follow are

• Maintain a healthy lifestyle.

• Monitor blood pressure and cholesterol.

• Manage stress.

• Limit alcohol and tobacco.

• Follow a strict medication schedule.

 Conclusion

Regular checkups and monitoring can help maintain heart health and prevent complications. An ECG is an essential tool for looking into heart health, but abnormal ECG details may not always indicate a disease. Sometimes, they may be due to non-heart-related factors, lifestyle factors, or even technical factors. Gauze helps us evaluate them.