The snow-shoveler's ST elevation myocardial infarction

Abstract

Heavy snowfall, cold temperatures, and low atmospheric pressure during the winter months have been associated with increased adverse cardiovascular events. However, only a few cases of the "snow shoveler's infarction" have been reported. The investigators describe their experience with 6 patients presenting with ST elevation myocardial infarctions, all within a 24-hour period during an unprecedented snowfall (4 of whom were shoveling snow), and provide a detailed review of previously reported cases of snow shoveler's infarction. Consistent with other reports, most patients reported here had the traditional cardiac risk factors of hypertension, hyperlipidemia, diabetes mellitus, tobacco use, and sedentary lifestyle. Unique to this case series, however, was that the 4 patients who had histories of coronary artery disease and previous coronary artery stenting all presented with subacute stent thromboses documented on coronary angiography performed emergently. Moreover, these patients constituted 25% of all subacute stent thromboses diagnosed in the cardiac catheterization laboratory in the preceding 12 months. In conclusion, these findings suggest that in typically sedentary individuals with cardiac risk factors or histories of coronary artery disease, snow shoveling may trigger ST elevation myocardial infarction and therefore should be avoided. This may be most critical in patients with histories of coronary stent placement, considering that these findings suggest that snow shoveling may precipitate subacute stent thrombosis.

Figure 1

Daily number of patients with ST elevation myocardial infarction undergoing primary percutaneous coronary intervention at the University of Virginia from December 1, 2008 to December 31, 2009 (top panel), and daily number of patients with subacute stent thrombosis presenting with ST elevation myocardial infarction over the same time period (middle panel). The abrupt spike in the number of STEMI patients correlated with the large snowfall (inches) from December 18, 2009 to December 20, 2009, as recorded by the McCormick Observatory on the campus of the University of Virginia, Charlottesville, Virginia.

Figure 2

Hourly meteorological data as recorded by the McCormick Observatory on the campus of the University of Virginia, Charlottesville, Virginia. Temperature (top panel) in degrees Fahrenheit (°F) from 12 am December 18, 2009 to 3:57 pm, December 20, 2009; atmospheric pressure (middle panel) in inches of mercury (in Hg) from 12 am December 18, 2009 to 3:06 pm, December 20, 2009; wind gusts (bottom panel) in miles per hour (mph) from 12 am December 18, 2009 to 4:37 pm, December 20, 2009.