Value Of Electrocardiogram In The Differentiation Of Hypertrophic Cardiomyopathy And Hypertensive Left Ventricular Hypertrophy

BackgroundHypertrophic cardiomyopathy (HCM) and hypertensive left ventricular hypertrophy (H-LVH) are the two most common causes of left ventricular hypertrophy (LVH), which can be a challenge to make the differential diagnosis between hypertensive heart disease and HCM associated with systemic hypertension. In general, greater maximal Left ventricular wall thickness, asymmetric septal hypertrophy and dynamic left ventricular outflow tract obstruction are clues of HCM; on the contrary, concentric LVH is often associated with H-LVH. Nevertheless, there is overlap between HCM and H-LVH. In addition, techniques such as cardiovascular magnetic resonance imaging and doppler myocardial imaging are not available all the time.ObjectiveTo differentiate HCM from H-LVH by analyzing Tp-e (T peak to T end) interval and other ECG parameters.MethodsPatients who were admitted to the Peking Union Medical College Hospital from January 1st 2000 to December 31th 2014 and fulfilled the clinical diagnostic criteria of HCM or hypertension with LVH were enrolled. All the patients should also meet the criteria of the wall thickness ≥13 mm in posterior left ventricular wall or septum, and be excluded with other related cardiac disorders.Results1. Fifty-six patients were enrolled in the H-LVH group, and fifty-one patients were enrolled in the HCM group.2. Tp-e interval in precordial leads V5 and V6 were significantly prolonged in HCM versus H-LVH (P<0.05); Tp-e interval in precordial leads V1 to V4 were not significantly different (P>0.05).3. Tp-e and cTp-e interval in limb leads Ⅰ, Ⅱ, aVF and aVR were significantly prolonged in HCM versus H-LVH (P<0.05). The area under the receiver operating characteristic curve of Tp-e interval in leads Ⅱ was 0.805, which was the largest among all the ECG parameters of repolarization.4. Maximal Tp-e and cTp-e, and minimal Tp-e and cTp-e in all the leads were prolonged in HCM versus H-LVH (p<0.05). The value of the above 4 parameters, however,were not superior to Tp-e interval in leads Ⅱ,V6 or aVF.5. Mean maximal cQTe were prolonged in both HCM and H-LVH, with no significant difference between the two groups (p<0.05).6. Among HCM patients over 30 years old, abnormal Q wave was most common in leads Ⅲ,aVF,and V4 to V6, and could also be found in leads Ⅱ,V1,aVL and V2.7. The sensitivity and specificity of abnormal Q wave (Q wave> 1/4 of the ensuing R wave in depth and/or>0.04 s in duration in at least two leads except aVR) in diagnosing HCM were 20% and 95.3% respectively.8. The frequency of LVH definied by Sokolow-lyon or cornell criteria of LVH, and strain pattern were not significantly different in HCM and H-LVH (P<0.05). The sensitivy of Sokolow-lyon or cornell criteria in idenfying LVH in both HCM and H-LVH were less than 40%. The combination of Sokolow-lyon, cornell criteria and strain pattern to identify LVH could raise the sensitivity to 60-70%.9. The speicificy and sensitivity of T wave inversion (>3 mm in depth) in diagnosing HCM were 83.9% and 33.3% respectively.10. The sensitivity, specificity, positive likelihood ratio and negative likelihood ratio of fulfilling one of the ECG parameters (Tp-e interval ≥75 ms in lead Ⅱ, Tp-e interval ≥70 ms in lead V6, cQTe interval ≥460ms in lead Ⅲ or abnormal Q wave (Q wave >1/4 of the ensuing R wave in depth and/or>0.04 s in duration in at least two leads except aVR) to diagnose HCM were 60.8%,92.9%,8.51 and 0.42 respectively.Conclusions1. Tp-e interval in lead Ⅱ was the best ECG parameter of repolarization to differentiate HCM from H-LVH.2. Abnormal Q wave and T wave inversion could also provide diagnostic help for the differential diagnosis of HCM and H-LVH.3. The value of maximal Tp-e and cTp-e, and minimal Tp-e and cTp-e in diagonising HCM were not superior to Tp-e in leads Ⅱ,V6 or aVF; QT interval, QT dispersion and ECG criteria of LVH were of no help in differentiating HCM and H-LVH.4. The criteria of fulfilling one of the ECG parameters (Tp-e interval ≥75 ms in lead Ⅱ, Tp-e interval ≥70 ms in lead V6, cQTe interval ≥460ms in lead Ⅲ or abnormal Q wave in at least two leads except aVR) had a moderate sentivity and good specificity to diagnose HCM.