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Use the R-R interval. Cardiac cycle time = heart rate. R wave marks the reliable point on the ECG of ventricular depolarisation thus unlike atrial depolarisation (P-wave) it is less susceptable to conduction delays etc / heart block which can alter the cycle time (for example 2nd degree heart block where the P-R interval increases then is missing then restarts). Even if there is complete heart block or irregularly irregular rhythms such as atrial fibrillation the R-R interval will show the heart rate. This is due to the intrinsic rhythmicity of the ventricles and its ability to become it's own pacemaker in times of need :D
R-R interval / time = the electrical reflection of heart rate. NB: this tells you nothing about rhythm. for this you'd need to assess the P-R interval which tells you more about the relationship between the atria and the ventricles. also if you want to see HOW the electrical discharge spreads you'd have to look at the P-QRS-T components individually.
The reason why you wouldn't use the P-T interval is because it varies so much even in normal individuals with sinus arrhythmia. also it does not take into account the refractory phase of the cardiac cycle.
Hope this helps.
Sources: Hampton's ECG made easy, Lecture notes on cardiology
What else can I help you with?
What are the effects of adrenaline on ECG?
Adrenaline increases heart rate and conduction velocity in the heart, which can lead to changes in the ECG. These changes may include a shortening of the PR interval, widening of the QRS complex, and an increase in heart rate.
What is the difference between heart rate and ventricular rate?
On an ECG the heart rate will match both ventricular rate and atrial rate if the heart is normal. If people have atrial fibrilation then the ventricular rate will be used on the ECG to work out the rate of the ventricular contraction and vice-versa with ventricular fibrilation. Usually both atrial and ventricular rates match so if the atria contracts at 70 BPM the ventricles will beat at 70 BPM. It is possible for the ECG machine to work out atrial or ventricular rate if needs be. Usually, however, if the ECG machine just displays heart rate then both ventricular and atrial rates match.
What does the ecg wave tracing represent?
The ECG wave tracing represents the electrical activity of the heart as it beats. It shows the depolarization and repolarization of the heart muscle, which corresponds to specific events in the cardiac cycle. The different waves and intervals on the ECG tracing provide information about the heart's rhythm, rate, and potential abnormalities.
A person's can be determined by calculating his or her resting heart rate?
fitness level
What does ekg record?
Electrocardiograms (ECG's or EKG's to use the German) records the electrical activity of the heart. It shows the rhythm and rate of an individuals heart
How do you calculate respiratory rate from an ekg?
No there is not a direct connection. Typicly as heart rate increases it is in response to increased cardiac demand and respiratory rate increases accordingly.
How can the heart rate be determined from an ECG?
The heart rate can be determined from an ECG by measuring the distance between successive R-waves, which represent the peak of each heartbeat in the QRS complex. This interval, known as the R-R interval, can be used to calculate the heart rate by using the formula: Heart Rate (bpm) = 60 / R-R interval (in seconds). Alternatively, one can count the number of R-waves in a specific time frame (e.g., 10 seconds) and multiply that number by 6 to estimate the heart rate per minute.
Which line in the ECG should you read?
The main line to read on an ECG is the "QRS complex," which represents the ventricular depolarization. This is the most informative part in determining heart rate, rhythm, and conduction abnormalities.
What happens to the ECG when your heart speeds up?
An ECG stands for an electrocardiogram, a reading of the rhythm of your heart. What happens to the ECG when your heart speeds up is that the reading will change.
What disesease can be deduct from ECG?
ECG gives information about the rate, rhythm, and information about conduction of nerve impulses in the heart, evidence of damage to the heart from poor blood supply or previous heart attack, and of course changes to suggest recent heart attack. It is therefore useful to diagnose atrial flutter, fibrillation, heart block, ischaemic changes and heart attack
What is an ECG and what is it?
An ECG test is a non-invasive procedure that records the electrical activity of the heart at rest. Insight Medical Imaging offers ECG exams on a walk-in basis at most of our locations across Alberta. All ECG exams require a doctor’s requisition, Alberta Health Care card, and photo identification. ECG tests can be used to assess heart rate, rhythm, blood pressure, and other symptoms such as palpitation or chest pain. x-ray.ca/services/walk-in-ecg/
What three characteristics of a heartbeat can be determined by examining an ECG?
An electrocardiogram (ECG) can reveal several characteristics of a heartbeat, including the heart rate, which is determined by the frequency of the R-R intervals; the rhythm, which indicates whether the heartbeat is regular or irregular; and the cardiac axis, which provides information about the direction of electrical activity in the heart. Additionally, the ECG can also highlight any abnormalities in the heart's electrical conduction pathways and overall heart health.
