In the younger group, CHD and cardiomyopathies were significantly more common, whereas in the latter, coronary and hypertensive heart diseases were much more prevalent. Not unexpectedly, the nature of cardiac disease associated with AQW differed markedly between Group 1 and Group 2. AQW were also a strong indicator of cardiac disease in most patients in Group 2 subjects (76 of 82 cases or 92.7%). The high incidence of CHD and cardiomyopathies in this group reflects in part the special clinics at UCLA dealing with these ailments (The Ahmanson‐UCLA Center for Adult Congenital Heart Disease, and The Ahmanson‐UCLA Cardiomyopathy Center), and the institution's active program of cardiac transplantation. In the younger patients of Group 1, despite the low incidence of MI, the presence of AQW was strongly indicative of organic heart disease (74 of the 82 cases or 90.2%). Table 2 lists the incidence of different cardiac diagnoses in the two groups. Q and R deflections were defined, and their amplitudes and durations were measured by hand and eye according to the guidelines in the Minnesota Code. In tracings meeting criteria for left anterior fascicular block, a QS in V 2 was not considered abnormal if no other potential AQW were present. A QS deflection in lead V 1 can be a normal variant and was not considered abnormal if an initial R was present in V 2. These somewhat arbitrary definitions were an eclectic compilation derived from a variety of sources,īut relied heavily on the Minnesota Code.įor simplicity, leads III, aVR, and aVL were ignored in this compilation, as QR or QS complexes can occur normally in the latter two leads, and in a given case pathologic Q waves almost never are limited to lead III or aVL. Their medical records were similarly reviewed so incidences of MI associated with the AQW could be compared in the two age groups.ĪQW were defined as described in Table 1. A random sample of 82 cases was taken during the same years of ECGs from subjects over age 40 years who had similarly defined AQW and adequate imaging or serial ECG information to document the presence or absence of MI (Group 2). Particular attention was paid to myocardial imaging studies such as echocardiography, myocardial nuclear scintillation scans, cardiac magnetic resonance imaging, prior ECGs, coronary arteriography, and ventriculography. Medical records of these cases were reviewed to determine the cause of the AQW and the presence or absence of MI. Eighty‐two cases meeting these criteria were found (Group 1). Cases were excluded for the following reasons: age under 18 years age equal to or greater than 40 years absence of clinical information sufficient to render a cardiac diagnosis and to rule in or out MI technical inadequacy sufficient to obviate interpretation abnormal ventricular activation due to incomplete or complete left bundle branch block, ventricular preexcitation, ventricular pacing, idioventricular rhythms, or ventricular tachycardia obviously incorrect lead placement and patient duplication. During 2002–2004 all cases were systematically reviewed. The review from 1997 to 2002 was not systematic, and some cases were missed. Most tracings were recorded by Marquette Models MAC6, MAC8, MAC15, or MACVU ECG machines (GE Marquette Electronics, Milwaukee, WI, USA), and printed out for inspection at paper speed of 25 mm/s and amplitude of 1 mV = 10 mm. In this laboratory, about two‐thirds of ECGs come from outpatients. In the population studied, MI was present in only a small minority of subjects under 40 years of age with AQW, but was usually present in older subjects with similar AQW.ĮCGs processed through the Electrocardiography Laboratory of the UCLA Medical Center in the years 1997–2004 were reviewed by the author to select those with AQW in subjects between ages 18 and 40 years. Some types of AQW were more useful than others in ruling MI in or out.Ĭonclusions: AQW were a strong indicator of organic heart disease in both adult age groups, but their utility to indicate MI was age‐dependent. Etiologies of cardiac disease differed between younger and older subjects. Results: Cardiac disease was present in 90.2% and 92.7% of the younger and older subjects, respectively, whereas MI was present in only 15.9% of younger subjects and in 68.3% of older subjects. Methods: Eighty‐two subjects under 40 years of age with AQW were compared with 82 subjects from the same institution aged ≥40 years with similar AQW to determine the presence or absence of cardiac disease or MI. As an imperfectly specific sign of MI, the usefulness of AQW in identifying MI depends on its incidence in the population studied. Background: Abnormal Q waves (AQW) in the electrocardiogram are commonly ascribed to underlying myocardial infarction (MI).
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