A long-range restriction map of human chromosome 5q21-q23.

A long-range restriction map encompassing the APC (adenomatous polyposis coli) gene has been constructed. The map includes 35 DNA markers and consists of two segments of 10 and 2.5 Mb. Published genetic markers have been connected using additional, nonpolymorphic DNA probes. The map clarifies marker order and allows comparison of physical and genetic data.

Evaluation of a QRS scoring system for estimating myocardial infarct size. VIII. Specificity in a control group with left ventricular hypertrophy and proposal of a new scoring system for use with this confounding factor.

Electrocardiographic differentiation between left ventricular hypertrophy (LVH) and myocardial infarction (MI) is often difficult because both diagnoses are based primarily on QRS changes on the electrocardiogram (ECG). The specific goal of this study was the development of ECG criteria that could be used with the complete Selvester QRS scoring system for MI size in patients with LVH. A study population of 127 patients had significant aortic valve disease verified by cardiac catheterization. Inclusion in the study required no significant coronary artery disease, no focal contraction abnormality on the left ventriculogram, and no documented MI. Quantitative criteria for LVH developed by Bonner (IBM) and also those developed by the Cornell group were used to determine the ECG evidence for LVH in each patient. One or both sets of criteria were met in 110 (87%) of the 127 patients. This group was compared to a previously evaluated control population of 500 normal subjects. The complete 54-criteria, 32-point QRS MI size scoring system was applied to the 12-lead ECG of both groups. The score was 98% specific in the normal controls and 73% specific in the LVH group using a score of greater than 3 points as diagnostic for MI. Of the 54 individual QRS criteria, 16 failed to achieve 95% specificity in the LVH population: 13 were for anterior (and apical), 2 for inferior, and 1 for posterior locations. Of these 16, minor modifications to 11 were sufficient to achieve the 95% specificity standard.(ABSTRACT TRUNCATED AT 250 WORDS)

Performance of new criteria for right ventricular hypertrophy and myocardial infarction in patients with pulmonary hypertension due to cor pulmonale and mitral stenosis.

Historically, electrocardiographic criteria for right ventricular (RV) hypertrophy has achieved high specificity but low sensitivity. Recently, however, Butler-Leggett et al. have introduced three criteria that attained a 66% sensitivity in a population with RV hypertrophy due to mitral stenosis while maintaining a 95% specificity in an extensive normal control group. Electrocardiographic diagnosis of RV hypertrophy is principally dependent on changes in the QRS complex that may be masked or mimicked by myocardial infarction (MI). This dilemma has been confirmed by documentation of the low specificity of both the Selvester QRS scoring system for MI size estimation (greater than 3 points) and its screening subset (greater than 0 points) in a pure mitral stenosis population. This study introduces the population characterized by RV hypertrophy due to cor pulmonale, which has a mean pulmonary arterial systolic pressure that is higher than the mean for the mitral stenosis population and consequently suggests more severe RV hypertrophy. When compared, the Butler-Leggett criteria for RV hypertrophy are more sensitive in the new population than in the mitral stenosis population (89% versus 60%) and the Selvester QRS scoring system is less specific (12% versus 60%). Three sequential steps are suggested for electrocardiographic analysis: (1) diagnosis of RV hypertrophy using the Butler-Leggett criteria, (2) diagnosis of MI using the Selvester screening criteria in those patients with step 1 negative, and (3) estimation of MI size using the complete Selvester scoring system in patients with step 1 negative and step 2 positive.

Identification of electrocardiographic criteria for diagnosis of right ventricular hypertrophy due to mitral stenosis.

Current electrocardiographic (ECG) criteria for diagnosing right ventricular hypertrophy (RVH) have low sensitivity. In this study maximally specific and sensitive ECG criteria for RVH due to mitral stenosis (MS) were developed that incorporated the principles derived from spatial changes in the QRS complex observed on the vectorcardiogram and any existent ECG criteria that supplement the diagnostic capability of the criteria derived from the vectorcardiogram. The standard 12-lead electrocardiograms of a control group of 500 consecutively selected subjects with 50 women and 50 men in each decade between ages 20 and 69 years were compared with the electrocardiograms of a study population of 50 patients with RVH due to MS. Inclusion criteria were a diagnosis of MS by catheterization, normal coronary arteriographic and left ventriculographic findings and no other valvular abnormalities. It was hypothesized that patients with RVH resulting from MS would have QRS forces that are maximally anterior (A) and rightward (R) and minimally posterolateral (PL); thus, the A + R - PL value in the study group would be greater than that in the control group. The subsequently derived formula criterion (A + R - PL greater than or equal to 0.7 mV) and 2 additional criteria, R less than or equal to 0.2 mV in lead I and P less than 0.25 mV in leads II, III, aVF, V1 or V2, were tested in both groups. The specificity and sensitivity of each individual criterion was determined; when combined, the criteria yielded 94% specificity and 64% sensitivity. Moderate to severe RVH due to MS was detected in two-thirds of the patients using the proposed criteria.