MYOCARDIAL INFARCTION
Posted by admin on November 25th, 2009In the USA, most patients hospitalized with acute myocardial infarc¬tion are > 65 yr of age. The elderly are less likely to have precordial pain and more likely to have dyspnea, fatigue, weakness, orCNS symp¬toms such as confusion and dizziness. The different symptomatology may reflect the greater likelihood that an older person has preexisting cerebrovascular disease or heart failure.
The incidence of infarct complications, including heart failure, pul¬monary edema, ventricular rupture, and death, is significantly higher in older palients. Again, these changes may result from preexisting left ventricular dysfunclion and possibly from lower contractile reserve in noninlareted regions related to diminished ?-agonist responsiveness. Older patients are also more likely to have smaller and non-Q-wavc infarcts than are younger persons. This may be because the elderly are more likely to have hypotension and superimposed illnesses, such as pneumonia or anemia, which may induce a small, non-Q-wave infarc¬tion in the absence of associated coronary thrombus. Important topo¬graphic changes—regional dilation and thinning in (he infarcted area and compensatory hypertrophy in noninfarcted lissue—that occur af-ier Q-wave infarction are also related to advancing age.
Treatment
Because of a high complication rale, elderly persons benefit from close monitoring in a coronary care unit.
Early thrombolysis (within 6 h of a transmural infarction) decreases mortality and improves left ventricular function. The addition of aspirin 160 mg/day provides more benefit than that achieved with thrombolysis
alone. However, thrombolytic therapy is not used as often in older pa¬tients with acute infarctions. This may be related in part to the in¬creased likelihood of coexisting illnesses, delayed presentation, and atypical symptoms and ECG changes. Although the elderly are at in¬creased risk for intracerebral hemorrhage, the risk may be attenuated if the dose of thrombolytic agent is weight-adjusted. When assessing the benefit-to-risk ratio, the physician should remember that the benefit of thrombolytic therapy is increased in those who are treated early and in Ihose who have extensive anterior infarctions.
Drug therapy is otherwise the same as that used in younger patients. However, because the elderly have a markedly heterogeneous re¬sponse, with no strict age-related rules, therapy must be individualized. Anticoagulants arc given cautiously for two major reasons: (1) heparin is associated with an increased risk of bleeding in older women, and (2) the hazards of chronic warfarin therapy are compounded by the in¬creased risk of falls. Aspirin is approved for prevention of reinfarction after myocardial infarction. Although studies have focused on middle-aged populations, it is reasonable and prudent lo give aspirin to the el¬derly as well. As in younger palients, ?-blockers may be used for their secondary prevention effects (see above). Such therapy is particularly beneficial for those who are at increased risk for recurrent myocardial infarction.
