I'm 54w.had an echo stress test.according to the 220-54 formula,my mhr is 166.was forced to get to168bpm although was very tired.can this harm my hrt?

Stress test: The rate should do no cardiac harm unless you had a significant coronary artery blockage that resulted in a myocardial infarction(heart attack) during the test. However,most stress tests strive for 85% of the maximum heart rate as the goal. You achieved more than 100% of your maximum heart rate and I presume you passed the test, showing no significant coronary blockages and good heart muscle funct