Sensitivity and specificity of commonly used EKG criterion to assess left ventricular hypertrophy in centenarians.

With the advent of improved technology and availability of newer diagnostic and therapeutic options life expectancy of an average American has increased resulting in the centenarian population (N/=100 years old) being encountered more frequently in clinical practice. Cardiovascular disease is still the most common cause of death in this subset of patients.We previously reported the echocardiographic characteristics of centenarians and found a high prevalence of hypertrophied left ventricles (LVH) in the elderly [1]. Left ventricular hypertrophy is associated with adverse cardiovascular events and increased morbidity and mortality. Various modalities available to diagnose LVH include EKG, Echocardiography, cardiac MRI, cardiac CT and various computer-assisted EKG analyses software. Even though more than a century old, EKG is still the preferred tool for detecting LVH; due to its low cost, easy availability, non-operator dependence, reproducibility & high specificity. JNC (Joint National Committee on Detection, Evaluation and Treatment of High Blood Pressure) recommends EKG as first line method to detect LVH in hypertensive patients. More than 30 EKG based criteria have been described to detect LVH [2]. Among the various EKG criteria to diagnose LVH—Sokolow–Lyon; Cornell & Romhilt–Estes criteria are the most commonly employed in routine clinical practice. Age has been reported to be an independent variable affecting sensitivity and specificity of EKG criteria even after adjustment for race, sex, BMI, and hypertension status [3]. In this study we assessed the best EKG criteria to detect LVH in centenarians as there is no data available supporting use of any particular criteria in this specific subgroup of patients. We retrieved all the electrocardiograms of all centenarians between 1998 and 2009 from our database (of 30,798 records), and detected electrocardiograms and simultaneously present echocardiograms for 72 centenarians—41 females (F) and 31 males (M) (baseline features in Table 1). We identified the 12-lead electrocardiogram done closest to the date of the echo. The electrocardiograms were reviewed by two researchers (AS and SC), independently and the measurements of the three different criteria for the assessment of LVH (Romhilt–Estes, Sokolow–Lyon, Cornell) were entered in duplicate to eliminate interobserver variability. This method produced good correlation between the two observations with a kappa statistic of 0.73. Where there was discrepancy between the two recordings, the original electrocardiogramwas retrieved and reassessed by the two researchers and reviewed with a cardiologist, together until a consensus was reached. The followingmeasurements were recorded independently by a panel of cardiologists: left ventricular (LV) end-diastolic dimension, LV end-systolic dimension, and an evaluation was made for the presence of LVH. LV end-diastolic dimensions and LV end-systolic dimensions were measured from the parasternal long-axis 2dimensional guided M-mode examination. In examinations for which M-mode was not properly aligned, measurements were taken directly from 2-dimensional imaging. The proportion of correctly identified LVH by the three criteria was then assessed using the echocardiogram results as the gold standard by using Z-statistics. Statistical comparisons were done using Stata Ver 11. As reported previously, we found a very high prevalence of left ventricular hypertrophy (87.5%) in centenarians. We determined that the Sokolow–Lyon criteriawere themost sensitive and specific to identify left ventricular hypertrophy in centenarians (sensitivity 84%, specificity 89%, positive predictive value 98%; p b 0.05 for all comparisons) (Table 2). Various EKG based LVH criteria have different sensitivity and specificity in different age group due to the use of the same voltage threshold [4]. To our knowledge, the present study is the first comparative study to assess the best EKG criteria to detect LVH in centenarians. After adjustment for concomitant risk factors, our data suggests that there is a very high prevalence of LVH in centenarians (even in those without clinical hypertension) and the Sokolow–Lyon criteria were the most effective in correctly identifying LVH in centenarians. Our results are in consensus with previous studies that age is an independent variable and affects diagnostic performance of various EKG based criteria to detect LVH even after adjusting for sex, hypertension status, race, smoking & BMI; hence it should be taken into consideration while selecting appropriate criteria [3]. When compared with the other commonly used criteria, the Sokolow–Lyon score allowed accurate diagnosis of LVH in a larger group of patients (higher sensitivity) which was comparable to the more expensive & subjective method—Echocardiography. One of the potential limitations of our study is that we did not correlate results of EKG based criteria to computer assisted criteria like computation of the QRS time-voltage integral or 12-lead voltageduration product which has been shown to improve accuracy to diagnose LVH [5]. Moreover, small sample size and inclusion of mostly Caucasian population could be other potential limiting factors which should be taken into consideration before extrapolation of results