European Journal of Cardiovascular Medicine

Hypertension remains one of the leading global health burdens, affecting an estimated 1.28 billion adults worldwide. Despite taking at least three antihypertensive medications, including a diuretic, a subgroup of these patients—who are diagnosed with resistant hypertension (RH)—are unable to maintain appropriate blood pressure management. This demographic is especially susceptible to myocardial infarction, stroke, and sudden cardiac death, among other adverse cardiovascular events2.

Left ventricular hypertrophy (LVH) is one of the key cardiac sign of chronic hypertension. LVH is a clinical condition that increases cardiovascular risk on its own in addition to being a structural adaptation. Early detection of LVH is therefore essential for risk assessment and aggressive BP control treatment3.

In clinical practice, electrocardiography (ECG) is still the most extensively used, affordable, and accessible screening method for LVH. The Romhilt-Estes (R-E) point score is one of the several ECG-based scoring systems that has long been renowned for its composite approach, which integrates several variables beyond basic voltage requirements1. Its diagnostic precision has been uneven, nevertheless, particularly in groups with concomitant conditions like obesity, chronic renal disease, or other conditions frequently associated with resistant hypertension.

In contrast, left ventricular mass and wall thickness may be directly seen and measured by echocardiography. Despite its limited availability and expense, it is regarded as the non-invasive reference standard for LVH testing.

This study investigates the correlation between LVH as detected by ECG using the Romhilt-Estes score and the LVM measured by echocardiography in a cohort of Indian patients with resistant hypertension. By doing so, we aim to clarify the utility and limitations of ECG as a surrogate for echocardiographic LVH in this high-risk population and to suggest periodic echocardiographic evaluation to see progression or regression of LVH during long-term treatment and follow-up of patients with resistant hypertension.

Study Design and Population:
This was a cross-sectional study conducted over 12 months at the Department of Cardiology, ABVIMS and Dr RML Hospital, New Delhi, India. A total of 95 patients aged ≥18 years with diagnosed resistant hypertension (defined as blood pressure >140/90 mmHg despite adherence to three antihypertensive medications, including a diuretic) were consecutively recruited.

Inclusion and Exclusion Criteria:
Inclusion criteria included adults with resistant hypertension attending cardiology outpatient services. Patients were excluded if they had previous coronary interventions, heart failure (NYHA Class IV), significant valvular or congenital heart disease, cardiomyopathies, or advanced renal dysfunction (GFR ≤30 mL/min/1.73 m²).

Procedures:
All participants underwent thorough clinical evaluation, including history, physical examination, routine laboratory tests (CBC, KFT, LFT, thyroid profile, blood glucose), and BMI calculation. A standard 12-lead ECG was recorded at 25 mm/s paper speed and 10 mm/mV calibration using GE equipment. LVH was defined using Romhilt-Estes point score, with ≥5 points indicating definite LVH, 4 points indicating probable LVH, and ≤3 as no LVH¹.

Echocardiography:
Two-dimensional transthoracic echocardiography was performed using Philips equipment. LV mass (LVM) was calculated using the Devereux formula and indexed to body surface area (LVMI). LVH was defined as LVM >224 g (men) or >162 g (women), and LVMI >115 g/m² (men) or >95 g/m² (women)¹.

Statistical Analysis:
Clinical factors and demographics were analyzed using descriptive statistics. For continuous variables, Pearson correlation was employed. The correlation between ECG and echo-based LVH was evaluated using the inter-rate agreement (kappa coefficient). The gold standard for calculating sensitivity, specificity, and predictive values was echocardiography. A p-value of less than 0.05 was deemed significant. SPSS v25.0 was used for statistical analysis.

Among the 95 patients, mean age was 55.2±12.3 years with a male predominance (74.7%). Most patients were obese (61.1%) and had comorbidity as diabetes (25.3%).

ECG Findings:
Based on Romhilt-Estes scoring, 36.8% had definite LVH, 14.7% had probable LVH, and 48.4% had no LVH.

Echocardiographic Findings:
LVH was observed in 50.5% based on absolute LVM and in 82.1% based on indexed LVMI. Mean LVM was significantly higher in those with echocardiographic LVH (247.1±44.9 g vs 179.1±32.5 g; p<0.0001).

Correlation and Agreement:
Agreement between ECG and echocardiographic LVH was poor (kappa < 0.06). Sensitivity and specificity of ECG were 53.3% and 55.6%, respectively, with a diagnostic accuracy of 53.7%. LVMI showed a weak negative correlation with BMI (r = -0.33; p = 0.001).

Table : Inter-rater agreement between LVH on ECG and LVH on Echo.

Table : Sensitivity, specificity, positive predictive value, negative predictive value of LVH on ECG after taking LVH on Echo as gold standard.

Figure: Sensitivity, specificity, positive predictive value, negative predictive value of LVH on ECG after taking LVH on Echo as gold standard.

Our study highlights the limitations of ECG-based detection of LVH in patients with resistant hypertension. When compared to Echo criteria, the Romhilt-Estes scoring system showed limited specificity and modest sensitivity, while being an easily available instrument.

A number of variables, such as thoracic architecture, obesity, and interstitial myocardial abnormalities like fibrosis that impact voltage transmission, all contribute to the poor diagnostic performance of ECG. These are common in people with resistant hypertension, many of whom also have chronic renal disease and diabetes as comorbidities4.

Echocardiography remains the non-invasive gold standard for assessing left ventricular structure. In our study, over 80% of patients had echocardiographic evidence of LVH based on indexed values, while ECG only identified 36.8% with definite LVH. These findings are consistent with prior literature indicating ECG’s low sensitivity and high specificity5.

The weak negative correlation between BMI and LVMI also suggests that body composition significantly affects electrical signal propagation thereby altering ECG voltages6. As such, reliance on ECG alone may underestimate true LVH burden in RH populations.

Overall, the results confirm the necessity of echocardiography in assessing cardiac target organ damage in Resistant Hypertension, especially in settings with limited resources where clinical judgments frequently depend significantly on ECG.

The Romhilt-Estes ECG scoring method has poor agreement with echocardiography in detecting left ventricular hypertrophy in individuals with resistant hypertension. It is not advisable to utilize ECG alone as a stand-in for LVH evaluation, particularly in high-risk patients. In this population, echocardiography is still essential for precise LVH identification and risk assessment.

1. Hamed M, Dasari G, Casale JA, Kaur N, Karl M. The Use of Romhilt-Estes Criteria in the Presumptive Electrocardiographic Diagnosis of Left Ventricular Hypertrophy in Comparison to Voltage-Based Criteria. Cureus. 2022;14(8).
2. Calhoun DA, Jones D, Textor S, Goff DC, Murphy TP, Toto RD et al. Resistant hypertension: diagnosis, evaluation, and treatment: a scientific statement from the American Heart Association Professional Education Committee of the Council for High Blood Pressure Research. Hypertension. 2008;51(6):1403-19.
3. Robertson JIS. Introduction:, hypertension, Ischaemic Heart disease and Left ventricular hypertrophy. In left ventricular Hypertrophy in Hypertension. Royal soc. of Med International Congress and Symposium series. 1978;9:1.
4. Bacharova L. Missing link between molecular aspects of ventricular arrhythmias and QRS complex morphology in left ventricular hypertrophy. International Journal of Molecular Sciences. 2019;21(1):48.
5. Dhodary S, Uranw S, Pandey NK, Karki P. Comparative Study of Electrocardiographic and Echocardiographic Evidence of Left Ventricular Hypertrophy in Systemic Hypertension. Age. 2021;58:11-27.
6. Cuspidi C, Rescaldani M, Sala C, Grassi G. Left-ventricular hypertrophy and obesity: a systematic review and meta-analysis of echocardiographic studies. Journal of hypertension. 2014;32(1):16-25.