Basic Arrhythmias Exam Questions with Complete Answers Latest Update

Basic Arrhythmias Exam Questions with Complete Answers Latest Update What is the primary pacemaker site of the heart and its intrinsic rate - Answers SA node 60-100 What are the two escape pacemaker sites and their intrinsic rates - Answers AV 40-60 and ventricle 20-40 What is the primary function of the AV node and why is it important - Answers It catches and delays the impulse, so the ventricles can fill=atrial kick What value of time is associated with a small box - Answers .04 What value of time is represented between time line markers at the edge of EKG paper? - Answers 6 seconds, make sure it is 15 boxes Which leads are referred as limb leads - Answers 1,2,3 What does the P wave represent? - Answers atrial depolarization (contraction) What does the QRS wave represent? - Answers ventricular depolarization (contraction) and atrial repolarization (relaxation) What is normal qrs duration - Answers 0.12 seconds What is the normal range for PR interval - Answers .12-.20 seconds What does the T wave represent? - Answers Ventricular repolarization (ventricular relaxation) When does the absolute refractory period begin and end? - Answers Starts at Q and ends at middle of T When does the relative refractory period occur? - Answers Mid T to end of T What is the heart rate if the R-R interval is exactly 3 large boxes apart - Answers 100 NSR: rhythm, rate, p wave, pr interval, QRS - Answers Rhythm = regular Rate = 60-100 P wave = same size, shape, and deflection 1:1 PR interval = 0.12 -0.20 seconds QRS = .12 or less Normal QT interval - Answers .45 sec or the QT is less than half of the R-R What is atrial kick - Answers Towards the end of ventricular filling, left atrium contracts (atrial kick), pumping remaining 30% of blood into right ventricle and left ventricle. cardiac output - Answers stroke volume x heart rate Depolarization - Answers An electrical event that results in muscle contraction which is a mechanical event Myocardial muscle cells - Answers Contraction and relaxation (mechanical) Myocardial pacemaker cells - Answers Nodes, bundles, and branching networks-the conduction of electrical activity AV node - Answers Secondary pacemaker (junctional rhythm). 40-60 bpm Perkinje fibers - Answers 20-40 bpm competing pacemakers (ventricular pacemakers) idioventricular rhythms QRS - Answers ventricular depolarization (contraction) and atrial repolarization happens at this same period of time 1 big box time - Answers .20 seconds How many small boxes in a big box - Answers 5 across (5x5 technically) How many seconds are 5 big boxes - Answers 1 second negative deflection - Answers the downward presentation of waveforms on the EKG tracing that is located below the isoelectric line P wave from atria - Answers May appear small, pointed, or biphasic, as a small squiggle, wavy or sawtooth. Occasionally negative (inverted) if the ectopic site is close to AV junction. P wave from AV junction - Answers Usually negative in lead two, may proceed or follow QRS , or be hidden behind qrs and not visible. What is normal pr interval? What happens if it is greater than or less than the normal time? - Answers Normal PRI is 0.12-0.20. If it is .12 sec then it is generated from the av junction. when it is .20 sec and it is a first degree av block QRS time if impulse is originated from ventricles - Answers .12 seconds. BBB is a type of block for wide QRS What is the J point? - Answers Where the QRS meets the ST segment Elevates st segment - Answers MI (stemi), coronary artery spasm, acute pericarditis, ventricular aneurysm, hyperkalemia, hypothermia Depressed ST segment - Answers MI, NSTEMI, reciprocal changes associated with STEMI, hypokalemia, digitalis effects-causes sagging ST T wave - Answers This is when 70% of blood from atria pours into ventricles. It is when the ventricles repolarize Inverted T wave - Answers MI, left ventricular hypotrophy, metabolic abnormalities Peaked T waves - Answers hyperkalemia, or very early sign of MI How long should normal QT be? - Answers Less than half of R-R, and accurate measurement of the QT interval can be done only when the rhythm is regular for at least 2 cardiac cycles before the measurement absolute refractory period - Answers Cardiac cell is unable to respond to an electrical stimulus. Beginning of qrs to mid t wave relative refractory period - Answers Enough cells repolarized that can now be depolarized again. But it can only occur with a stronger than normal stimulus Why is relative refractory period sensitive - Answers It is a vulnerable period because PVC's during this period may take over control of the heart in the form of v tach (most commonly torsades). Can turn to R on T PVC Prolonged QT interval - Answers Results in a lengthed relative refractory period which puts the ventricles at risk for life threatening arrhythmias such as torsades de pointes v tach. frontal plane (coronal plane) - Answers Standard limb leads 1,2,3 Divides the body into front and back portions. transverse plane (horizontal plane) - Answers Precordial or chest leads v1-v6 Calculating rate using the 6 second method - Answers -do not include premature beats to hr count. The premature beat is considered another rhythm. Count number of normal QRS in 6 seconds then multiply that by 10 or count number of normal qrs in three seconds and multiply that by 20 Heart rate calculation precise method - Answers 1500 small boxes divided by the number of small boxes between two consecutive R waves. Use box method only if rhythm is regular, if the rhythm is irregular then use 6second method Big Box Method (ECG) - Answers 300 divided by however many big boxes there are between R-R What are the different sinus rhythms - Answers NSR, Sinus brady, sinus tachy, sinus arrhythmias, sinus arrest, sinus block Wide QRS - Answers bundle branch block. It means ventricles dont contract at the same time, they contract at different times