Watch the video version of this Q&A episode on YouTube - https://youtu.be/r_NwDbjyBAo

Before beginning to train for a wheelchair racing event, a 40-year-old patient with complete C7 tetraplegia undergoes a graded exercise test using an upper body ergometer. In the absence of cardiac pathology, which value represents the patient’s MOST likely maximum heart rate?

1. 60 beats per minute
2. 80 beats per minute
3. 120 beats per minute
4. 190 beats per minute

Transcript

Welcome back to the Scorebuilders’ Question and Answer Podcast! This podcast provides members of the Scorebuilders’ team with the opportunity to explore challenging multiple-choice examination questions with students actively preparing for the licensing examination. My name is Scott Giles and I will be your host for today’s journey.

Ready? Let’s go!

Before beginning to train for a wheelchair racing event, a 40-year-old patient with complete C7 tetraplegia undergoes a graded exercise test using an upper body ergometer. In the absence of cardiac pathology, which value represents the patient’s MOST likely maximum heart rate?

1. 60 beats per minute
2. 80 beats per minute
3. 120 beats per minute
4. 190 beats per minute

Let’s briefly explore maximum heart rate.

Maximum Heart Rate
The target heart rate for exercise can be grossly approximated using a percentage of the maximum heart rate, which can be estimated as 220 – age. With an age-predicted approach, 70-85% of maximum heart rate or 50-70% of maximum oxygen uptake (VO2max) would be the recommended exercise intensity according to the American College of Sports Medicine.

The question indicates that the patient’s age is 40, therefore:
Maximum Heart Rate is 180 beats per minute (220 – 40 = 180)

Because of sympathetic nervous system impairment, patients with T3 or higher complete spinal cord injuries typically have difficulty reaching age-adjusted maximum and target training heart rate zones. Heart rate responses are more variable with injuries between T4 and T6, while patients with injuries below T7 are typically able to reach age-adjusted ranges. 

Let’s explore each of the options:

Option 1 - 60 beats per minute 
The 60 beats per minute could come up as soon as the option does and then the % of age adjusted maximum heart rate could come in below it when I express this in the audio. In the last option it would just be the beats per minute value.

A heart rate of 60 beats per minute or below would be considered bradycardia. The value represents only 33% of the patient’s age-adjusted maximum heart rate. Acutely, patients with complete upper thoracic or cervical lesions commonly experience a period of bradycardia due to an interruption of the sympathetic nervous system. However, this typically resolves in a matter of weeks following the initial injury.

Option 2 - 80 beats per minute 
A patient with C7 complete tetraplegia will typically have a lower maximum heart rate and target training zone as compared to a non-injured individual. 80 beats per minute represents only 44% of the patient’s age-adjusted maximum heart rate and therefore would be unlikely to represent their maximum heart rate.

Option 3 - 120 beats per minute 
The sympathetic impairment associated with complete spinal cord injuries will impact numerous aspects of a patient’s response to exercise (e.g., heart rate, stroke volume, sweating, vasodilation). 

In the general population of patients with complete lesions above T3, achieving maximum heart rate values from 110-120 bpm is considered typical. This value represents 67% of the patient’s age-adjusted maximum heart rate.

Option 4 - 190 beats per minute
Based on the patient’s age, 190 bpm would be above the patient’s age-predicted maximum heart rate. This heart rate level would be unattainable given the patient’s level of injury.

The correct answer is Option 3

Let’s explore the all student data:
2% of students selected Option 1 - 60 beats per minute
9% of students selected Option 2 - 80 beats per minute
63% of students selected Option 3 - 120 beats per minute – the correct response
26% of students selected Option 4 - 190 beats per minute

System Classification
This question is a Neuromuscular and Nervous Systems question which represents approximately 24% of all exam items.

Content Outline Classification
This question is a Physical Therapy Examination question which represents approximately 24% of all exam items.

Level Classification
This question is a Level 2 question since the question requires students to integrate numerous pieces of information or to apply knowledge in a given clinical scenario. Remediation of Level 2 questions occurs by increasing flexibility with academic content and by carefully analyzing decision making processes when answering applied examination questions.

Thanks for joining us on the Scorebuilders Q and A podcast! See you next week!