Baylor University Medical Center Proceedings April 2017 - 235

Figure 1. Specific skydiving testing and exercise training: (a) metabolic stress test wearing a helmet and a 20-pound chute-pack harness; (b) right arm line pull to
measure muscular strength; (c) belly-fly exercise training drill.

customized to simulate the sport of skydiving (Figure 1c). The
patient's blood pressure was measured before and after exercise.
In keeping with the standard protocol of our CR program,
we used telemetry (TeleRehab VersaCare, ScottCare Corp.,
Cleveland, OH) to monitor the patient's electrocardiogram.
The patient's pacemaker was evaluated 6 times over the course
of CR by an electrophysiology nurse specialist. These device
interrogations were done using the manufacturer's programmer
(Biotronik PSW 1307.U, Biotronik, Inc., Lake Oswego, OR)
to retrieve data and analyze the device settings. Each device
interrogation consisted of a lead impedance test, an electrogram
amplitude or sensing test, a capture threshold test, and retrieval
of any recorded arrhythmias. The parameter criteria, according
to the American College of Cardiology and the American Heart
Association, were as follows: 1) the sensitivity threshold was
2.4 mV in the atrium (P waves) and 4.8 mV in the ventricle (R
waves); 2) for pacing threshold, the loss of capture was 0.06 V at
0.4 ms in the atrium and 5.3 V at 1.0 ms in the ventricle; and 3)
atrial lead impedance values were approximately 290 Ω and
ventricular lead impedance was 312 Ω. The electrophysiology
nurse specialist reviewed each transmission for proper functioning of the device and for the presence of arrhythmias.
CR staﬀ (registered nurses and exercise physiologists) provided telemetry monitoring, testing, and exercise training. The
testing and exercise training were symptom regulated, and as
such were monitored for the peak rate-pressure product threshold (>36,000) (2), angina pectoris, dizziness, pain, dyspnea,
lead displacement, and arrhythmias. Peak heart rate and blood
pressure measurements were successfully recorded (18 out of
25 sessions). During the sessions, the patient's heart rate, blood
pressure, and rating of perceived exertion remained within acceptable ranges (means, 153 beats/min, 160/73 mm Hg, and
7, respectively). His mean peak rate-pressure product value
(24,624) was consistent with the 36,000 threshold. The patient achieved 9.65 metabolic equivalents (METS, deﬁned as
the energy cost of exercise, where 1 MET = 3.5 mL O2 per kg
of body weight per minute) on the post-CR program metabolic
stress test. He also demonstrated gains in muscular strength
April 2017

(mean change = 22.5%) on the post-CR program static force
gauge tests. Physiological data obtained during these tests are
shown in the Table. Over the course of the exercise sessions, various arrhythmias were noted: occasional preventricular contractions, couplets and triplets, and one 4-beat run of preventricular
contractions; all were deemed clinically insigniﬁcant by the
CR staﬀ. The patient had no adverse events or symptoms that
required the discontinuation of any exercise session.
The patient attended iFLY Dallas during exercise sessions 10
and 14, where he performed skydiving maneuvers including the
belly-ﬂy (Figure 2a), sit-ﬂy, and head-up. There were no adverse
events or symptoms during the performance of these maneuvers.
To simulate the force of the chute-pack harness on his torso
and, thus, the pacemaker leads, the patient reported to CR on
exercise session 23 to perform a simulated free-fall drop test
(Figure 2b). Before the test began, an electrophysiology nurse
specialist performed a device interrogation in which appropriate
lead placement was conﬁrmed. The patient and CR staﬀ then
Table. Physiological data from pre- and post-cardiac
rehabilitation program tests designed to replicate
the patient's specific skydiving goal activities
Category

Test

Muscular strength test: Left maximum grip
Line grip (lb)
Right maximum grip

Pre

Post Change

82.9 86.4

93.2 97

Left sustained grip

79.9 82.1

Right sustained grip

76.7 89.6

17%

Muscular strength test: Right line pull
Line pull (lb)
Left line pull

Muscular strength test: Abdomen extension
Fly position (lb)
Rotate right
Rotate left

22%

65%

139

53%

21%

16%

Skydiving cardiovascular Oxygen volume (mL/kg/min) 33 33.8
treadmill tests
Metabolic equivalents
9.42 9.65

Cardiac rehabilitation for a skydiver

2%
2%

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