| A | B |
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| Normal Sinus Rhythm | REGULARITY: The R-R intervals are constant; the rhythm is regular. RATE: The atrial and ventricular rates are equal; heart rate is between 60 and 100 beats per minute. P WAVE: The P waves are uniform. There is one P wave in front of every QRS complex. PRI: The PR interval measures between .12 and .20 seconds; the PRI measuresment is constant across the strip. QRS: The QRS comples measures less than .12 seconds. |
| Sinus Tachycardia | REGULARITY: The R-R intervals are constant; the rhythm is regular. RATE: The atrial and ventricular rates are equal; the heart rate is greater than 100 beats per minute (usually between 100 and 160 beats per minute). P WAVE: There is a uniform P wave in front of every QRS complex. PRI: The PR interval measures between .12 and .20 seconds; the PRI measurement is constant across the strip. QRS: The ORS measures less than .12 seconds |
| Sinus Bradycardia | REGULARITY: The R-R intervals are constant; the rhythm is regular. RATE: The atrial and ventricular rates are equal; heart rate is less than 60 beats per minute. P WAVE: There is a uniform P wave in front of every QRS complex. PRI: The PR interval measures between .12 and .20 seconds; the PRI measuresment is constant across the strip. ORS: The ORS complex measures less than .12 seconds constant; the rhythm is regular. |
| Atrial Flutter | REGULARITY: The atrial rhythm is regular. The ventricular rhythm will be regular if the AV node conducts impules through in a consistent pattern. If the pattern varies, the ventricular rate will be irregular. RATE: Atrial rate is between 250 and 350 beats per minute. Ventricular rate will depend on the ratio of impules conducted through the ventricles. P WAVE: When the atria flutter they produce a series of well-definded P waves. When seen together, these "flutters" waves have a sawtooth appearance. PRI: Because of the unusual configuration of the P wave (flutter wave) and the proximity of the wave to the QRS complex, it is often impossible to determine a PRI in this arrhythmia. Therefore, the PRI is not measured in Atrial Flutter. QRS: The QRS complex measures less than .12 seconds; measurement can be difficult if one or more flutter waves is concealed within the QRS complex |
| Atrial Tachycardia | REGULARITY: The R-R intervals are constant; the rhythm is regular. RATE: The atrial and ventricular rates are equal; the heart rate is usually 150-250 beats per minute. P Wave: There is one P wave in front of every QRS complex. Teh configuration of the P wave will be different than that of sinus P waves; they may be flattened or notched. Becasue of the rapid rate, the P waves can be hidden in the T waves of the preceding beats. PRI: The PRI is between .12 and .20 seconds and constant across the strip. The PRI may be difficult to measure if the P wave is obscured by the T wave. QRS: The QRS complex measures less than .12 seconds |
| Atrial Fibrillation | REGULARITY: The atrial rhythm is unmeasureable; all atrial activity is chaotic. The ventricular rhythm is grossly irregular, having no pattern to its irregularity. RATE: The atrial rate cannot be measured becasue it is so chaotic; research indicates that it exceeds 350 beats per minute. The ventricular rate is significantly slower becasue the AV node blocks most of the impules. It the ventricular rate is below 100 beats per minute, the rhythm is said to be "controlled"; if it is over 100 beats per minute, it is considered to have a "rapid ventricular response". P WAVE: In this arrhythmia the atria are not depolarizing in an effective way; instead, they are fibrillating. Thus, no P wave is produced. All atrial activity is depicted as "fibrillatory" waves, or grossly chaotic undulations of the baseline. PRI: Since no P waves are visible, no PRI can be measured. QRS: The QRS complex measurement should be less than .12 seconds |
| Wenckebach Type I Second Degree Heart Block | REGULARITY: The R-R interval is irregular in a pattern of grouped beating. The R-R interval gets progressively shorter as the PRI gets progressively longer. RATE: Since some beats are not conducted, the ventricular rate is usually slightly slower than normal. The atrial rate is normal. P WAVE: The P waves are upright and uniform. Some P waves are not followed by QRS complex. PRI: The PR intervals get progressively longer, until one P wave is not followed by a QRS complex. After the blocked beat, the sysle starts again. QRS: The QRS complex measurement will be less than .12 seconds |
| First Degree Heart Block | REGULARITY: This will depend on the regularity of the underlying rhythm. RATE: The rate will depend on the rate of the underlying rhythm. P WAVE: The P waves will be upright and uniform. Each P wave will be followed by a QRS complex. PRI: The PRI will be constant across th entire strip, but it will always be greater than .20 seconds. QRS: The QRS complex measurement will be less than .12 seconds |
| Complete Heart Block | REGULARITY: Both the atrial and the ventricular foci are firing regularly, thus the P-P intervals and the R-R intervals are regular. RATE: The atrial rate will usually be in a normal range. The ventricular rate will be slower. If a junctional focus is controlling the centricles, the rate will be 40-60 beats per minute. If the focus is ventricular, the rate will be 20-40 beats per minute. P WAVE: The P waves are upright and uniform. There are more P waves than QRS complex. PRI: Since the block at the AV node is complete, none of the atrial impulses are conducted through to the ventricles. There is no PRI. The P waves have no relationship to the QRS complex. You may occasionally cee a P wave superimposed on the QRS complex. QRS: If the ventricles are being controlled by a junctional focus, the QRS complex will measure less than .12 seconds. If the focus is ventricular, the QRS will measure .12 seconds or greater. |
| Type II Second Degree Heart Block | REGULARITY: If the conduction ratio is consistent, the R-R interval will be constant, and the rhythm will be regular. If the conduction ratio varies, the R-R will be irregular. RATE: The atrial rate is usually normal. Since many of the atrial impulses are blocked, the ventricular rate will usually be in the bradycardia range, often one half, one third, or one forth of the atrial rate. P WAVE: The P waves are upright and uniform. There are wlaways more P waves than QRS complex. PRI: The PRI on conducted beats will be constant acrosee the strip, although if might be longer than a normal PRI measurement. QRS: The QRS complex measruement will be less than .12 seconds |
| Ventricular Tachycardia | REGULARITY: This rhythm is usually regular, although it can be slightly irregular. RATE: Atrial rate cannot be determined. The ventricular rate range is 150-250 beats per minute. If the rate is below 150 beats per minute, it is considered a slow VT. If the rate exceeds 250 beats per minute, it is called Ventricular Flutter. P WAVE: None of the QRS complexes will be preceded by P waves. You may see dissociated P waves intermittently across the strip. PRI: Since the rhythm originates in the ventricles, there will be no PRI. QRS: The QRS complexes will be wide and dizarre, measureing at least .12 seconds. It is often difficult to differentiate between the QRS and the T wave. |
| Premature Ventricular Contractions | REGULARITY: The underlying rhythm can be regular or irregular. The ctopic PVC will interrupt the regularity of the underlying rhythm Iunless the PVC is interpolated). RATE: The rate willbe determined by the underlying rhythm. PVCs are not usually included in the rate dtermination becasue they frequently do not produce a pulse. P WAVE: The ectopic is not preceded by a P wave. You may see a coincidental P wave near the PVC, but it is dissociated. PRI: Since the ectopic comes from a lower focus, there will be no PRI. QRS: The QRS complex will be wide and bizarre, measureing at least .12 seconds. The configuration will differ from the configuration of the underlying ORS complexes. The T wave is frequently in the opposite direction from the QRS complex. |
| Ventricular Fibrillation | REGULARITY: There are no waves or complexes that can be analyzed to determine regularity. The baseline is totally chaotic. RATE: The rate cannot be determined since there are no discernible waves or complexes to measure. P WAVE: Thre are no discernible P waves. PRI: There is no PRI. QRS: There is no discernible QRS complexes |
| Sympathetic Branch | Affects the atria and the ventricles. Increases heart rate, conductin and irritability |
| Parasympathetic Branch | Affects only the atria. Decreases heart rate, conduction and irritabilty |
| Measuring PRI | The PRI is measured from the beggining of the P wave to the beginning of the QRS complex. The normal PRI is .12 - .20 seconds |
| Measuring QRS | The QRS is measured from the beginning of the Q wve to the end of the S wave. The QRS is normally <.12 seconds. |
