https://en.ecgpedia.org/api.php?action=feedcontributions&user=200.226.134.53&feedformat=atomECGpedia - User contributions [en]2024-03-29T13:14:43ZUser contributionsMediaWiki 1.39.5https://en.ecgpedia.org/index.php?title=Introduction&diff=5379Introduction2007-11-04T11:50:46Z<p>200.226.134.53: </p>
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<div>acchia<br />
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|mainauthor= [[user:Drj|J.S.S.G. de Jong, MD]]<br />
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[[Image:nsr.png|thumb| A short ECG registration of normal heart rhythm (sinus rhythm)]]<br />
The aim of this course is to understand and recognize the normal ECG and to be able to interprete abnormalities. The course is divided in two different sections. First the [[basics]] will be presented. This is followed by the interpretation of the normal ECG according to the 7+2 step plan:<br />
* Step 1: [[Rhythm]]<br />
* Step 2: [[Rate]]<br />
* Step 3: [[Conduction]] (PQ,QRS,QT)<br />
* Step 4: [[Heart axis]]<br />
* Step 5: [[P wave morphology]]<br />
* Step 6: [[QRS morphology]]<br />
* Step 7: [[ST morphology]]<br />
* Step 7+1: [[Compare_the_old_and_new_ECG|Compare the current ECG with a previous one]]<br />
* Step 7+2: [[Conclusion]]<br />
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Finally the real world is presented through [[Cases and Examples|practice ECGs]].<br />
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If you have finished the course you are invited to come back to read more about abnormal ECGs in the ECG textbook.<br />
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Also read our [[Frequently Asked Questions]] section.<br />
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<div>nomonernoo<br />
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==What is the heart rate?==<br />
[[Image:ECGpapier.png|thumb| The width of a square on the ECG represents time]]<br />
[[Image:Ecgfreq.png|thumb| The countmethod to determine the heartfrequency. The second QRS-complex is between ''75'' and ''60'' beat per minute. This heartbeat is between that, around 65 beats per minute.]]<br />
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To anwer this question, determine the time between two QRS complexes. Previously, the ECG was registered on a paperstrip transported through an ECG writer at the speed of 25 mm/second. Nowadays, digital ECG registration is common however, the method of determining the frequency remains the same. The ECG paper has a grid with thick lines 5 mm apart (= 0,20 second) and thin lines 1 mm (0,04 second). <br />
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'''There are three simple methods to determine the heart rate (HR):'''<br />
# Count the small (1mm) squares between two QRS-complexes. Hense, the ECG paper runs with 25 mm/sec through the ECG writer, therefore:&nbsp;&nbsp;&nbsp;[[Image:HFformule_en.png]]This method works well in case of tachycardia (>100 beats/minute)<br><br />
# To determine the frequency of a normal sinus ritme: Use the sequence 300-150-100-75-60-50-43-37. Count from the first QRS complex, the first thick line is 300, the next line 150 etc. Stop the sequence at the next QRS complex. When the second QRS complex is in between two lines, take the mean of the two numbers from the sequence or use the finetune method listed to the right.<br />
# Non regular rhytms are best determined with the "3 second marker method" Count the number of QRS-complexes that fit in 3 seconds (some ECG writers register this period on the ECG paper). Multiply this number by 20 and find the number of beats/minute. <br />
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{| class="wikitable" font-size="90%" align="right" <br />
|+'''The 'square counting' method can be finetuned with the following sequence'''<br />
|-<br />
|'''300'''||250||214||187||167||'''150'''||136||125||115||107||'''100'''||94||88||83||79||'''75'''||71||68||65||62||'''60'''<br />
|-<br />
|}<br />
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==What changes the frequency of the heart?==<br />
A number of factors change the heart frequency including:<br />
* the (para) sympathic nerve system. <br />
** The '''sympathic system''' e.g. epinephrin (=adrenalin) increases the atrioventricular conduction and contractility. (the ''fight, fright, flight'' reaction)<br />
** The parasympathic system (nervus vagus) e.g. acetycholin decreases the frequency and atrioventricular conduction. The parasympathic system effects mainly the atria.<br />
* Cardiac filling increases the frequency.</div>200.226.134.53https://en.ecgpedia.org/index.php?title=Electrolyte_Disorders&diff=5377Electrolyte Disorders2007-11-04T11:50:27Z<p>200.226.134.53: </p>
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<div>delzelacre<br />
{{authors|<br />
|mainauthor= [[user:Drj|J.S.S.G. de Jong]]<br />
|moderator= [[T.T. Keller]]<br />
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===Hypercalcemia===<br />
Hypercalcemia results in a faster repolarization. Characteristics of hypercalcemia:<br />
*mild: broad based tall peaking T waves<br />
*severe: extremely wide QRS, low R wave, disappearance of p waves, tall peaking T waves.<br />
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===Hypocalcemia===<br />
ECG-characteristics of hypocalcemia:<br />
*narrowing of the QRS complex<br />
*reduced PR interval<br />
*T wave flattening and inversion<br />
*prolongation of the QT-interval <br />
*prominent U-wave<br />
*prolonged ST and ST-depression<br />
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===Hyperkalemia===<br />
[[Image:ecg_hyperkaliemie.jpg|thumb| Extreme hyperkalemia. No p-waves, wide QRS, tall peaking T waves.]]<br />
[[Image:ecg_hyperkaliemie2.jpg|thumb| Same patient after partial correction of the potassium level. Still no p-waves visible, wide QRS, tall peaking T waves.]]<br />
ECG characteristics of hyperkalemia:<br />
*Tall peaked T waves<br />
*Flattening p-waves. In extreme hyperkalemia p-waves may disappear altogether.<br />
*Prolonged depolarization leading to QRS widening (nonspecific intraventricular conduction defect) sometimes > 0.20 seconds<br />
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At concentrations > 7.5 mmol/L atrial and [[Ventricular Fibrillation|ventricular fibrillation]] can occur.<br />
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===Hypokalemia===<br />
[[Image:KJcasu18-3.jpg|thumb| Consecutive ECGs of a patient with hypokalemia. ECG1]]<br />
[[Image:KJcasu18-2.jpg|thumb| Consecutive ECGs of a patient with hypokalemia. ECG2]]<br />
[[Image:KJcasu18-1.jpg|thumb| Consecutive ECGs of a patient with hypokalemia. After correction of potassium levels.]]<br />
Hypokalemia is a low blood potassium level. This results in:<br />
*ST depression and flattening of the T wave<br />
*Negative T waves<br />
*A U-wave may be visible<br />
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