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Electrocardiogram

Electrocardiogram

An electrocardiogram (ECG or EKG) is a critical diagnostic tool that records the electrical signals produced by the heart during each heartbeat. This recording is achieved through electrodes placed strategically on the arms, legs, and chest. The electrocardiograph amplifies these signals and produces 12 distinct tracings, offering a comprehensive understanding of the heart's electrical activity.
Three major waveforms are present in a typical ECG recording: the P wave, the QRS complex, and the T...

Disturbances in Heart Rhythm

Disturbances in Heart Rhythm

Arrhythmia or dysrhythmia refers to an abnormal heart rhythm caused by a defect in the heart's conduction system. It can cause the heart to beat irregularly, too quickly, or too slowly, leading to symptoms like chest pain, shortness of breath, and fainting. Factors such as stress, caffeine, alcohol, nicotine, cocaine, certain drugs, congenital defects, diseases, and electrolyte abnormalities can trigger arrhythmias.
Arrhythmias are categorized by their speed, rhythm, and origin. A slow heart...

ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias

ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias

Arrhythmia is a condition characterized by an irregular heart rhythm, with ECG changes that differ based on its origin and nature. The types of arrhythmias discussed below include atrial, junctional, and ventricular arrhythmias.Atrial ArrhythmiasPremature Atrial Complexes (PACs): PACs are early atrial beats caused by stress, caffeine, alcohol, electrolyte imbalances, hypoxia, hyperthyroidism, or certain medications (e.g., bronchodilators and decongestants). The ECG shows early P waves with an...

Acute Coronary Syndrome II: Pathophysiology and Clinical Manifestations

Acute Coronary Syndrome II: Pathophysiology and Clinical Manifestations

The pathophysiology of Acute Coronary Syndrome [ACD] involves several key processes:The main underlying cause of ACD is atherosclerosis, a chronic inflammatory disease characterized by the buildup of lipid-laden plaques within the coronary arteries.As the atherosclerotic plaque grows in the coronary artery, it may become unstable due to the formation of a lipid-rich core and a thin fibrous cap. Inflammatory cells within the plaque, such as macrophages, secrete enzymes that degrade the...

Electrocardiogram Fundamentals

Electrocardiogram Fundamentals

Introduction
An electrocardiogram (ECG) is a diagnostic tool for identifying cardiac conditions such as arrhythmias, conduction abnormalities, and myocardial ischemia.
Definition
An electrocardiogram (ECG) visualizes the heart's electrical activity by tracing the electrical movement associated with each heartbeat on a graph or monitor. As the heart beats, an electrical wave passes through it, correlating with the cardiac cycle events.
Parts of an ECG
An ECG utilizes electrodes on the skin to...

ECG Interpretation of Arrhythmias I: Sinus Arrhythmias

ECG Interpretation of Arrhythmias I: Sinus Arrhythmias

Arrhythmias are disturbances in the heart's rhythm that lead to abnormal heartbeats. These irregularities can originate from different parts of the heart and are classified based on their origin and nature.
Types of Arrhythmias
Sinus Node Arrhythmias
Sinus Bradycardia: Originating from the sinoatrial (SA) node, sinus bradycardia involves slower impulses, resulting in a heart rate of less than 60 beats per minute (bpm). Causes include sleep, vagal stimulation, beta-blockers, hypothyroidism, and...

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Updated: May 28, 2026

A Research Method For Detecting Transient Myocardial Ischemia In Patients With Suspected Acute Coronary Syndrome Using Continuous ST-segment Analysis

A Research Method For Detecting Transient Myocardial Ischemia In Patients With Suspected Acute Coronary Syndrome Using Continuous ST-segment Analysis

Published on: December 28, 2012

Electrocardiographic changes in chronic severe anaemia.

Monika Maheshwari¹, Anil Baroopal

¹Department of Medicine, Jawaharlal Nehru Hospital, Ajmer 305001.

Journal of the Indian Medical Association

|October 21, 2011

Summary

This summary is machine-generated.

Electrocardiogram (ECG) in chronic severe anemia shows universally diminished QRS voltages. This may be due to a hyperdynamic circulatory state and myocardial scarring in anemic patients.

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Electrocardiogram Recordings in Anesthetized Mice using Lead II

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Last Updated: May 28, 2026

A Research Method For Detecting Transient Myocardial Ischemia In Patients With Suspected Acute Coronary Syndrome Using Continuous ST-segment Analysis

A Research Method For Detecting Transient Myocardial Ischemia In Patients With Suspected Acute Coronary Syndrome Using Continuous ST-segment Analysis

Published on: December 28, 2012

Electrocardiogram Recordings in Anesthetized Mice using Lead II

Electrocardiogram Recordings in Anesthetized Mice using Lead II

Published on: June 20, 2020

Area of Science:

Cardiology
Hematology

Background:

Chronic severe anemia, defined by hemoglobin < or = 5 g/dl, presents significant physiological challenges.
The cardiac manifestations of severe anemia are not fully elucidated, necessitating further investigation.

Purpose of the Study:

To analyze electrocardiogram (ECG) findings in patients with chronic severe anemia.
To compare ECG parameters between anemic patients and healthy controls.

Main Methods:

Electrocardiograms were analyzed from 35 patients with chronic severe anemia (hemoglobin <= 5 g/dl).
A control group of 35 age- and sex-matched healthy subjects was included for comparison.

Main Results:

A dominant finding of diminished QRS voltages was observed in 100% of anemic patients across all limb and precordial leads.
No specific ECG findings were detailed for the control group.

Conclusions:

Diminished QRS voltages are a consistent electrocardiographic finding in chronic severe anemia.
These ECG changes are likely attributed to a compensatory hyperdynamic circulatory state, myocardial scarring, and chronic fibrotic changes in the myocardium.