Background-Q waves on a 12-lead ECG are markers of a prior myocardial infarction (MI). However, they may regress or even disappear over time, and there is no specific ECG sign of a non-Q-wave MI. Fragmented QRS complexes (fQRSs), which include various RSRЈ patterns, without a typical bundle-branch block are markers of altered ventricular depolarization owing to a prior myocardial scar. We postulated that the presence of an fQRS might improve the ability to detect a prior MI compared with Q waves alone by ECG. Methods and Results-A cohort of 479 consecutive patients (meanϮSD age, 58.2Ϯ13.2 years; 283 males) who were referred for nuclear stress tests was studied. The fQRS included various morphologies of the QRS (Ͻ120 ms), which included an additional R wave (RЈ) or notching in the nadir of the S wave, or Ͼ1 RЈ (fragmentation) in 2 contiguous leads, corresponding to a major coronary artery territory. The Q wave was present in 71 (14.8%) patients, an fQRS was present in 191 (34.9%) patients, and an fQRS and/or a Q wave was present in 203 (42.3%) patients. Sensitivity, specificity, and the negative predictive value for myocardial scar as detected by single photon emission computed tomography analysis were 36.3%, 99.2%, and 70.8%, respectively, for the Q wave alone; 85.6%, 89%, and 92.7%, respectively, for the fQRS; and 91.4%, 89%, and 94.2%, respectively, for the Q wave and/or fQRS. Conclusions-The fQRS on a 12-lead ECG is a marker of a prior MI, defined by regional perfusion abnormalities, which has a substantially higher sensitivity and negative predictive value compared with the Q wave.

PURPOSE Azithromycin use has been associated with increased risk of death among patients at high baseline risk, but not for younger and middle-aged adults. The Food and Drug Administration issued a public warning on azithromycin, including a statement that the risks were similar for levofloxacin. We conducted a retrospective cohort study among US veterans to test the hypothesis that taking azithromycin or levofloxacin would increase the risk of cardiovascular death and cardiac arrhythmia compared with persons taking amoxicillin. METHODSWe studied a cohort of US veterans (mean age, 56.8 years) who received an exclusive outpatient dispensation of either amoxicillin (n = 979,380), azithromycin (n = 594,792), or levofloxacin (n = 201,798) at the Department of Veterans Affairs between September 1999 and April 2012. Azithromycin was dispensed mostly for 5 days, whereas amoxicillin and levofloxacin were dispensed mostly for at least 10 days.RESULTS During treatment days 1 to 5, patients receiving azithromycin had significantly increased risk of death (hazard ratio [HR] = 1.48; 95% CI, 1.05-2.09) and serious arrhythmia (HR = 1.77; 95% CI, 1.20-2.62) compared with patients receiving amoxicillin. On treatment days 6 to 10, risks were not statistically different. Compared with patients receiving amoxicillin, patients receiving levofloxacin for days 1 to 5 had a greater risk of death (HR = 2.49, 95% CI, 1.7-3.64) and serious cardiac arrhythmia (HR = 2.43, 95% CI, 1.56-3.79); this risk remained significantly different for days 6 to 10 for both death (HR = 1.95, 95% CI, 1.32-2.88) and arrhythmia (HR = 1.75; 95% CI, 1.09-2.82).CONCLUSIONS Compared with amoxicillin, azithromycin resulted in a statistically significant increase in mortality and arrhythmia risks on days 1 to 5, but not 6 to 10. Levofloxacin, which was predominantly dispensed for a minimum of 10 days, resulted in an increased risk throughout the 10-day period. Ann Fam Med 2014;12:121-127. doi: 10.1370/afm.1601. INTRODUCTIONA zithromycin is a macrolide antibiotic commonly prescribed for outpatient treatment of respiratory infections, urinary tract infections, and sexually transmitted diseases.1 Macrolide antibiotics, primarily erythromycin and clarithromycin, are known to increase cardiac arrhythmogenic risks, including QT interval prolongation, torsades de pointes, and polymorphic ventricular tachycardia.2 Between 2001 and 2007, case reports described arrhythmias among persons receiving azithromycin. [3][4][5][6][7] In 2012, Ray et al 8 reported increased risks of cardiovascular death and all-cause mortality among adult, predominantly female, Medicaid patients in Tennessee who received azithromycin compared with amoxicillin, particularly among those with a high baseline risk for cardiovascular disease. Subsequently, the Food and Drug Administration (FDA) 10 and pharmaceutical manufacturer issued public safety notifications warning of QT prolongation risks with azithromycin. Researchers from Denmark then reported that in comparison with penicillin V, azi...

From these 2 disparate population cohorts, we found that addition of Hcy level to FRS significantly improved risk prediction, especially in individuals at intermediate risk for CHD events.