Myocardial infarction affecting risk

Atrial fibrillation is commonly associated with heart failure, and the prevalence of atrial fibrillation is related to the severity of heart failure, with less than 5% affected with very mild heart failure to nearly 50% affected with advanced heart failure [66]. Heart failure and atrial fibrillation are both common cardiovascular disorders and share the same demographic risk factors, including age, history of hypertension, prior myocardial infarction, and valvular heart disease [67, 68]. Further, the incidence of heart failure increases dramatically after the diagnosis of atrial fibrillation [69]. Progression of LV dysfunction can clearly be associated with rapid ventricular rates [70-76]. Conversely, conversion to normal sinus rhythm or control of ventricular response in atrial fibrillation can improve LV function [71-74, 77]. Accordingly, rate control becomes very important in patients with heart failure and dilated cardiomyopathy, and likely even more so when ischemia from rapid rates complicate the patient s course. 

Cardiovascular safety. Both drug types promote salt retention, can exacerbate heart failure and tend to raise blood pressure. COX-2 selective drugs also appear to raise the risks of thrombotic events, notably stroke and myocardial infarction, and recent evidence suggests that non-selective NSAIDs also raise these risks, though it is unclear whether to the same degree. For both drug types, dose and duration of treatment appear to affect risk. 

Iacoviello L, Di Castelnuovo A, Gattone M, Pezzini A, Assanelli D, Lorenzet R et al. Polymorphisms of the interleukin-lbeta gene affect the risk of myocardial infarction and ischemic stroke at young age and the response of mononuclear cells to stimulation in vitro. Arterioscler Thromb Vase Biol 2005, 25(l) 222-227. 

The humanized mouse model is used for safety assessment of drugs that affect lipid profiles as a side effect (and thereby possibly influence the risk of atherosclerosis and, subsequently, myocardial infarction). A typical example is the disturbed lipid profile and increased risk of myocardial infarction experienced by AIDS patients following the long-term use of HIV-l-protease inhibitors [16,17]. 

There has been some concern that the shorter-acting calcium channel blockers may adversely affect the risk of myocardial infarction and cardiac death. The evidence is based on case-control studies which cannot escape the possibility that sicker patients, i.e. with worse hypertension or angina, received calcium charmel blockade. The safety and efficacy of the class has been strengthened by the recent findings of two prospective comparisons with other antihypertensives. ... 

In a systematic review, the beneficial interaction has been confirmed (249). Four groups of patients who had been studied in EMIAT and CAMIAT (SEDA-21, 198) were defined patients who had taken amiodarone plus beta-blockers, patients who had taken beta-blockers or amiodarone alone, and patients who had taken neither. The relative risks for all-cause mortality and all forms of cardiac death or resuscitated cardiac arrest were lower in the patients who had taken amiodarone plus beta-block-ers than in the other three groups. The results of this post hoc analysis should be regarded with caution, but in view of previous similar reports they are suggestive of a beneficial interaction of amiodarone with beta-blockers in patients who have had a previous myocardial infarction. The interaction was statistically significant for cardiac deaths and for dysrhythmic deaths or resuscitated cardiac arrest. In all other cases the relative risk was reduced, although not significantly. The risk was not affected by heart rate. This interaction has been reviewed (250). 

Helgadottir, A., Thorleifsson, G., Manolescu, A., Gretarsdottir, S., Blondal, T., Jonasdottir, A., Sigurdsson, A., Baker, A., Palsson, A., Masson, G. et al. 2007. A common variant on chromosome 9p21 affects the risk of myocardial infarction. Science 316 1491-1493. 

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