January 28th, 2011
She Doesn’t Mind that Her Heart Races … Do You?
This latest installment in our case discussion series is submitted by Alfonso E. Sierra, MD. We encourage members to submit cases that they believe warrant discussion. Selected cases will be presented to the community, and case authors will receive a $100 Amazon gift card.
A 62-year-old woman comes in for a routine exam, with a history of sudden death on both sides of her family. Her paternal grandfather died suddenly in his 40s, her father in his mid-70s, and her maternal grandmother in her mid-90s; her maternal grandfather told her that many of his relatives also died suddenly at various ages. Her 60-year-old brother has angina and syncope and was found on an angiogram to be a candidate for angioplasty, which is pending.
The patient herself has no symptoms other than tachycardia during exercise, which has been happening for more than 35 years without any palpitations, pain, dyspnea, diaphoresis, or fainting. She notes that the episodes start suddenly, only during exercise, and that her heart rate often reaches 180 to 190 beats/minute. She usually feels her heart returns to its normal resting rate (86-89 beats/min) within a minute or so after she stops her workout. The occurrence of the tachycardia does not appear to be related to her clinical condition, the intensity or duration of the exercise, or the humidity or temperature of the room. The patient is curious about why it happens but is not concerned about it and is not eager to be treated if there is no need.
Her physical examination is normal, other than a resting pulse of 88. Her blood pressure is 108/62. She has been menopausal since her mid-50s and has no signs or symptoms of hypo- or hyperthyroidism. Her CRP and ESR levels are normal, as are her total and LDL cholesterol levels; her HDL is 66. Her resting ECG is normal for a woman her age.
- Would you conduct any further tests to evaluate the nature/etiology of this patient’s exercise-induced tachycardia?
- Would you suggest any treatment to prevent the tachycardia during exercise?
- Would you advise her to restrict her activity in any way?
- Would her family history influence your treatment decision in any way?
James Fang, MD
Most of the CardioExchange members who responded to this case indicated that they would evaluate this patient further before treating her symptoms or restricting her activity in any way. I agree. Although her symptoms and family history together are somewhat concerning, the gradual cool down and chronicity of her symptoms are reassuring, as are the normal results on her physical exam, EKG (most importantly, intervals), and basic laboratory tests. Furthermore, she has not experienced any syncope or presyncope.
Exploring family history is always important, and this patient’s is notable. Most genetic cardiovascular conditions are autosomal dominant, and her family history does appear to affect every generation, as would be anticipated with this mode of inheritance. However, in familial sudden death syndromes, the deaths usually occur by age 35 or 40. Most sudden deaths are caused by coronary artery disease (CAD), but the risk for ventricular fibrillation with CAD can be inherited as well (Circulation 1999; 99:1978). The ages of sudden death in this family would certainly be consistent with CAD.
An exercise test would be reasonable in this case, with particular attention to the patient’s QT interval during exercise and to the increases and declines in her heart rate. Her high resting heart rate may be due to lack of vagal tone, as is seen in patients who are deconditioned (e.g., those with impaired heart rate recovery). The exercise test would have only modest predictive value for CAD screening, but current guidelines recommend it over imaging as a first test (Circulation 2002; 106:1883). At this point, without a diagnosis, treating this patient or restricting her activity would be premature.