Bruce protocol, 5:00 minutes, 6 METS*, %MPHR, non-limiting chest pain
2. REPORT ON RESTING ECG
-including whether there was any ST segment deviation
3. REPORT ON STRESS ECG.
- when the ST depression began, in what leads it was seen
- what the maximum ST depression was
- how long all ST changes took to normalize
4. Positive**/negative/equivocal(inconclusive)/uninterpretable stress test for inducible myocardial ischaemia at a submaximal/maximal workload. Duke treadmill score of -18 and early onset of significant ECG changes indicate high risk for a cardiac event. No inducible arrhythmias.
5. Whether there was baseline hypertension, exercise induced hypertension/exaggerated BP response to exercise.
6. Whether there is normal or reduced exercise capacity.
7. What the heart rate recovery at 1 minute was.
- <12bpm (or <22bpm at 2 minutes) is poor heart rate recovery predictor of events
->12bpm is satisfactory
Bruce Protocol Stage Min % grade MPH METS1 3 10 1.7 4.72 6 12 2.5 7.03 9 14 3.4 10.14 12 16 4.2 12.95 15 18 5.0 15.0
...so, after stage 1 which is 5 mets, you calculate METS by tripling the stage number and adding 1.
Duke Treadmill Score
Score = Exercise time - (5x ST deviation) - (4x Angina index)
- Angina Index
- 0 = none
- 1 = during test
- 2 = angina stopped test
- Probability of Mortality
- Low > = 5
- Moderate -10 to +4
- High < -10
MAXIMUM PREDICTED HEART RATE:
The most common formula encountered, with no indication of standard deviation, is:
- HRmax = 220 − age
This is attributed to various sources, often "Fox and Haskell," and was devised in 1970 by Dr. William Haskell and Dr. Samuel Fox.[4] Inquiry into the history of this formula reveals that it was not developed from original research, but resulted from observation based on data from approximately 11 references consisting of published research or unpublished scientific compilations.[5] It gained widespread use through being used by Polar Electro in its heart rate monitors,[4] which Dr. Haskell has "laughed about",[4] as it "was never supposed to be an absolute guide to rule people's training."[4]
While the most common (and easy to remember and calculate), this particular formula is not considered by reputable health and fitness professionals to be a good predictor of HRmax. Despite the widespread publication of this formula, research spanning two decades reveals its large inherent error (Sxy=7-11 b/min). Consequently, the estimation calculated by HRmax=220-age has neither the accuracy nor the scientific merit for use in exercise physiology and related fields.[5]
A 2002 study[5] of 43 different formulae for HRmax (including the one above) concluded the following:
- 1) No "acceptable" formula currently existed, (they used the term "acceptable" to mean acceptable for both prediction of
, and prescription of exercise training HR ranges)
- 2) The formula deemed least objectionable was:
-
- HRmax = 205.8 − (0.685 × age)
- This was found to have a standard deviation that, although large (6.4 bpm), was still considered to be acceptable for the use of prescribing exercise training HR ranges.
Other often cited formulae are:
- HRmax = 206.3 − (0.711 × age)
-
- (Often attributed to "Londeree and Moeschberger from the University of Missouri–Columbia")
- HRmax = 217 − (0.85 × age)
-
- (Often attributed to "Miller et al. from Indiana University")
- HRmax = 208 − (0.7 × age)
-
- (Another "tweak" to the traditional formula is known as the Tanaka method. Based on a study of literally thousands of individuals, a new formula was devised which is believed to be more accurate [6])
** Positive stress test defined as 1mm of flat or downsloping ST depression at J+80, or 1.5mm upsloping at J+80
