click below
click below
Normal Size Small Size show me how
TL Rhythm Strips
Interpretation of Rhythm Strips
Question | Answer |
---|---|
What is the normal firing rate of the SA node? | 60 -100 beats/min |
What are 5 defining characteristics of Sinus Rhythm? | Regular Rhythm, Rate 60-100, P wave for every QRS, PR interval between 0.12 to 0.20, QRS 0.06 – 0.12, |
Describe the path of conduction in Sinus Rhythm. | impulse originates in SA node, conducts through both atria, slows at the AV node, then accelerates through the bundle of HIS, right and left bundle branches, and through both ventricles (purkinje fibers) |
Describe 5 characteristic of Sinus Tachycardia. | regular rhythm, rate >100bpm, Pwaves for each QRS (but may be hidden in T waves), PR 0.12 – 0.20 (May be hidden in T wave), QRS 0.06-0.12 – Just like NSR but faster |
What normal conditions would create Sinus Tachycardia? | exercise, emotions |
What abnormal conditions can create Sinus Tachycardia at rest? | fever, blood loss, anxiety, heart failure, pain, hypermetabolic states, anemia |
Name 7 drugs that can cause Sinus Tachycardia? | Atorpine, Isoproterenol, Epinephrine, Dopamine, Dobutamine, Norepinephrine, nitroprusside, caffeine |
What is the physiologic effect of Sinus Tachycardia? | ST increases the hearts oxygen demand, decreases ventricular filling time and coronary artery perfusion time |
How should Sinus Tachycardia be treated? | Treat the cause |
What drugs could be used to slow sinus rate? | digitalis, beta blockers, calcium channel blockers, antiarrhythmics, sedatives |
What are the characteristics of Sinus Bradycardia? | regular rhythm, rate 40-60 beats/min, Pwave for every qrs, PR 0.12 – 0.20, QRS 0.06 – 0.12, Looks like NSR only slower |
Name some common normal causes of sinus bradycardia. | a well conditioned/athletic heart, during sleep, vagal stimulation |
Give some examples of vagal nerve stimulation. | carotid sinus massage, ocular pressure, vomiting, vagal maneuver |
Name some abnormal conditions that would create sinus bradycardia. | inferior wall MI, myxedema, obstructive jaundice, uremia, increased ICP, glaucoma |
What drugs could produce Sinus Bradycardia? | digitalis, beta blockers, CCBs, anti-arrhythmics |
When would treatment be appropriate for Sinus Bradycardia? | when symptoms such as chest pain, dizziness, hypotension, dyspnea |
What is the treatment of choice for Sinus Bradycardia? | Atropine 0.5mg IV |
Describe the characteristics of Sinus Arrythmia. | Rhythm is irregular but corresponds to breathing – faster on inspiration, slower on exhalation; Rate 60-100 beats/minute, P-waves normal and one for every qrs, PR are 0.12 to 0.20, QRS 0.06 to 0.12 |
What is the treatment for sinus arrhythmia? | No treatment necessary unless there is symptomatic bradycardia – Then Atropine 0.5 mg IV. This may be a normal rhythm for elderly and pediatric patients. |
What are the characteristics of PACs? | Rhythm irregular due to early beats, rate 60-100, p wave for every QRS but early ones look different or buried in preceding T wave, normal or long (very early PACs don’t give the atria time to get out of refractory stage), QRS normal, aberrant, or absent |
Explain the variations of QRS complexes in the presence of premature atrial complexes. | normal if PAC occurs after ventricles & AV node have repolarized, Aberrant & wide if the ventricles or bundle branches are in the relative refractory period, Absent if the PAC conducts during the complete refractory period of the AVnode/bundle branches |
In which patients are PACs commonly found? | those with pulmonary disease, congestive heart failure, MI, anxiety, hypermetabolic states |
What drugs can cause PACs? | caffeine, nicotine, alcohol |
What is the clinical significance of PACs? | PACs are not dangerous in and of themselves but may indicate atrial irritability (possibility of more significant atrial arrhythmias developing) |
What is the treatment for PACs? | No treatment necessary unless atrial irritability needs suppression to prevent more serious arrhythmias. Quinidine, disopyramide, and procainamide are useful to suppress PACs |
What is the path of conduction in the case of PACs? | PACs start in the atria but not the SA node. The path through the AV node, bundle branches, and ventricles is usually normal unless the beat come during the refractory period |
Describe the characteristics of Atrial flutter. | Atrial rhythm - regular, ventricular depends on AV block, rate - atrial 250-300, ventricular varies w AV block usually 150, rarely 300; Pwaves - like saw teeth (in 2:1 every other may be hidden in T wave), PR consistent or varying, QRS normal or aberrant |
Describe the conduction path of atrial flutter. | because of the extremely rapid rate the AV node blocks at least every other beat and often 2, 3, or more beats to protect the ventricles |
What is the clinical significance of Atrial Flutter? | loss of atrial kick decreases cardiac output, possibility for mural thrombi leading to pulmonary emboli or systemic emboli |
Name some conditions that can cause atrial flutter. | MI, Rheumatic heart disease, thyrotoxicosis, CHF, and ischemia |
What is the treatment for Atrial flutter? | slow ventricular rate with CCBs, BBs, or digitalis. Quinidine or procainamide may convert flutter to SR. If ventricular rates are very rapid or if flutter is resistant to drug therapy electrical cardioversion may be employed |