Practice: Mitral stenosis is a cardiac disease that can cause the atria to hypertrophy—develop more muscle and get bigger. This hypertrophy changes the way that the atria depolarize. Which of the following phases of the EKG is likely to be affected by atrial hypertrophy secondary to mitral stenosis?
Concept #1: EKG Waveforms-- P Wave, QRS Complex, T Wave
Concept #2: EKG Intervals and Segments
Concept #3: Relationship Between EKG and Cardiac APs
Concept #4: EKGs, Heart Rate, and Rhythm
Concept #5: Arrhythmias-- AV Blocks
Concept #6: The 12-Lead EKG
Practice: One of epinephrine’s effects on the heart is to speed up AV Node conduction—in the presence of epinephrine it takes less time for depolarization to spread from the atria to the ventricles. Which of the following parts of the EKG will be directly affected by this increase in AV Node conduction speed?
Practice: Which of the following parts of the EKG most closely corresponds to the time during which ventricular fibers are in the Ca2+ plateaus (i.e. Phase 2) in their action potentials?
Practice: A 15-year-old male receives his first kiss during the passing period between AP Biology and AP World History. Before the kiss, his heart rate was 66 beats/minute. After the kiss, his heart rate is 130 beats/minute. Which of the following describes his current heart rhythm?
Practice: Refer to the Lead II electrocardiogram recording below for practice problems 5-6.
Which of the following is the rhythm shown in the EKG above?
Practice: Which of the following are acting as the pacemaking fibers for the atria?
