European Journal of Cardiovascular Medicine

Hypertension is a major global health problem and one of the most important risk factors for cardiovascular morbidity and mortality. According to the World Health Organization, it affects more than 1.3 billion people worldwide, with a prevalence that continues to rise, particularly in low- and middle-income countries [1]. Persistent elevation of blood pressure induces structural and functional changes in the cardiovascular system, including left ventricular hypertrophy, impaired diastolic relaxation, and left atrial (LA) remodeling. Among its various complications, atrial fibrillation (AF) is of particular concern, as hypertension has been identified as the most common modifiable risk factor for the development and perpetuation of AF [2].

Atrial fibrillation is the most frequent sustained cardiac arrhythmia in clinical practice, with an estimated global prevalence of around 2–3% [3]. The burden of AF is expected to double in the coming decades due to aging populations and increasing prevalence of hypertension, diabetes, and obesity. AF significantly increases the risk of stroke, heart failure, hospitalization, and all-cause mortality [4]. Hypertension alone accounts for 14–22% of incident AF cases, and the risk of AF increases nearly twofold in hypertensive individuals compared to normotensive populations [5]. Early detection of subclinical atrial dysfunction in this population is therefore crucial for risk stratification and prevention of adverse cardiovascular outcomes.

The pathophysiological link between hypertension and AF is multifactorial. Chronic pressure overload leads to left ventricular diastolic dysfunction and elevated left atrial pressure. This hemodynamic burden contributes to atrial dilatation, wall stress, fibrosis, and conduction heterogeneity, collectively described as “atrial cardiomyopathy” [6]. Structural remodeling of the left atrium reduces its compliance and contractility, thereby impairing its reservoir, conduit, and booster pump functions. These changes precede the onset of clinically overt AF, highlighting the importance of identifying sensitive markers of atrial dysfunction before arrhythmia becomes established.

Traditionally, echocardiographic measurements of left atrial size, such as anteroposterior diameter and left atrial volume index (LAVI), have been used to assess atrial remodeling and predict AF risk [7]. However, these parameters primarily reflect late structural changes and are limited by their inability to capture early functional impairment. For instance, many patients with AF have normal or only mildly enlarged left atria, indicating that structural enlargement is not the sole determinant of arrhythmogenesis. Thus, reliance solely on left atrial size may underestimate risk in hypertensive patients with subclinical dysfunction.

Recent advances in echocardiographic imaging, particularly two-dimensional speckle-tracking echocardiography (2D-STE), have enabled more precise and reproducible assessment of myocardial deformation. Left atrial strain, derived from STE, provides quantitative information about atrial function throughout the cardiac cycle. LA strain is generally divided into three components: reservoir strain (reflecting LA compliance and storage of pulmonary venous return during ventricular systole), conduit strain (passive emptying of LA during early diastole), and contractile strain (active atrial contraction during late diastole) [8]. Among these, LA reservoir strain has emerged as a robust parameter for identifying early atrial dysfunction, often before structural dilatation becomes evident.

Multiple studies have demonstrated the prognostic significance of LA strain in various cardiovascular conditions. Reduced LA strain has been associated with diastolic dysfunction, heart failure with preserved ejection fraction (HFpEF), and increased risk of AF recurrence after catheter ablation or cardioversion [9]. In hypertensive patients, impaired LA strain has been observed even in the absence of significant left atrial enlargement, suggesting its potential role as an early marker of atrial remodeling. Furthermore, LA strain correlates strongly with invasively measured left ventricular filling pressures and provides incremental predictive value over conventional echocardiographic indices [10]. In this context, the present study aims to investigate the role of left atrial strain parameters in predicting atrial fibrillation among hypertensive patients. By comparing LA strain indices between patients who develop AF and those who remain in sinus rhythm, this study seeks to establish the utility of LA strain as a superior predictor compared to conventional LA size measurements. The findings are expected to provide valuable insights into the early detection of atrial dysfunction and contribute to improved risk stratification and management of hypertensive patients.

Study design: prospective observational study.

Place of study: Rims Ranchi.

Period of study: 1Year.

Study Variables:

• Age
• Male
• BMI
• Diabetes mellitus
• LVEF
• Reservoir Strain
• Conduit Strain
• Contractile Strain
• Duration of HTN

Sample size: 100 hypertensive patients without prior history of atrial fibrillation or significant structural heart disease.

Inclusion Criteria:

• Hypertensive patients aged ≥18 years.
• Patients in sinus rhythm at baseline.
• Willing to provide informed consent.

Exclusion Criteria:

• Prior history of atrial fibrillation or other significant arrhythmias.
• Structural heart disease or significant valvular pathology.
• Left ventricular ejection fraction <50%.
• Chronic kidney disease, thyroid dysfunction, or systemic illness affecting atrial function.
• Poor echocardiographic window precluding LA strain analysis.

Statistical Analysis: Statistical analysis was done using SPSS version 26.0 (IBM Corp., Armonk, NY, USA). Continuous variables were expressed as mean ± SD and compared using Student’s t-test or Mann–Whitney U test, while categorical variables were analyzed with Chi-square or Fisher’s exact test. ROC curve analysis determined cut-off values of LA strain, and multivariate logistic regression identified independent predictors of AF. A p-value <0.05 was considered statistically significant.

Table 1: Baseline Demographic and Clinical Characteristics

Table 2: Conventional Echocardiographic Parameters

Table 3: Left Atrial Strain Parameters (Speckle-Tracking Echocardiography)

Table 4: ROC Curve Analysis of LA Strain Parameters for Predicting AF

Table 5: Multivariate Logistic Regression for Predictors of AF

Figure 1: Comparison of Continuous Variables Between AF and Non-AF Groups

Figure 2: Baseline Characteristics of Study Participants

Patients who developed atrial fibrillation were older (62.8 ± 8.5 vs. 56.2 ± 7.9 years, p = 0.021) and had a longer duration of hypertension (11.6 ± 4.8 vs. 7.8 ± 3.9 years, p = 0.013) compared to those without AF. Although males (66.7% vs. 56.7%) and diabetes mellitus (40.0% vs. 23.3%) were more frequent in the AF group, the differences were not statistically significant (p = 0.52 and 0.29, respectively). Body mass index was similar between groups (27.4 ± 3.1 vs. 26.1 ± 2.9 kg/m², p = 0.19).

Patients who developed atrial fibrillation had significantly larger left atrial dimensions, with higher LA diameter (42.1 ± 3.8 vs. 38.4 ± 3.2 mm, p = 0.004) and LA volume index (38.6 ± 6.2 vs. 32.1 ± 5.1 mL/m², p = 0.001), along with elevated E/e’ ratio (13.4 ± 2.8 vs. 10.6 ± 2.3, p = 0.006), indicating increased filling pressures. Left ventricular ejection fraction (57.8 ± 5.6 vs. 59.6 ± 6.1%, p = 0.34) and LV mass index (116.2 ± 14.8 vs. 108.4 ± 13.7 g/m², p = 0.11) were slightly higher in the AF group but did not reach statistical significance.

Patients who developed atrial fibrillation demonstrated significantly impaired left atrial strain indices compared to those without AF. LA reservoir strain was markedly reduced in the AF group (19.2 ± 3.6 vs. 28.7 ± 4.1%, p < 0.001), as was conduit strain (9.4 ± 2.1 vs. 14.1 ± 2.8%, p < 0.001). Contractile strain was also lower in the AF group (7.8 ± 2.0 vs. 10.2 ± 2.3%, p = 0.011).

ROC curve analysis demonstrated that left atrial strain parameters had strong predictive value for atrial fibrillation. Reservoir strain showed the highest accuracy with an AUC of 0.89 and a cut-off ≤22.5%, yielding 86.7% sensitivity and 83.3% specificity (p < 0.001). Conduit strain also demonstrated good predictive performance (AUC 0.82, cut-off ≤11.2%, sensitivity 80%, specificity 76.7%, p = 0.002). Contractile strain had a lower predictive value with an AUC of 0.72 at a cut-off ≤8.5%, sensitivity 66.7%, and specificity 70% (p = 0.021).

Multivariate logistic regression analysis identified left atrial functional and structural parameters as significant predictors of atrial fibrillation. Longer duration of hypertension was independently associated with AF (OR 1.12, 95% CI 1.01–1.27, p = 0.037), as was higher LA volume index (OR 1.09, 95% CI 1.01–1.18, p = 0.028). Reduced LA reservoir strain emerged as the strongest predictor, with an OR of 0.81 (95% CI 0.70–0.92, p = 0.004), indicating that impaired atrial deformation substantially increased AF risk. Age and E/e′ ratio showed trends toward significance but did not reach statistical thresholds (p = 0.11 and 0.067, respectively).

Patients who developed atrial fibrillation in our study were significantly older and had a longer duration of hypertension compared to those without AF, consistent with previous literature highlighting age and hypertension as key determinants of atrial remodeling. Kume et al. reported that advancing age and long-standing hypertension contribute to increased atrial stiffness and interstitial fibrosis, thereby predisposing to atrial arrhythmogenesis [11]. Similarly, Tsang et al. demonstrated that cumulative hypertension exposure is a powerful predictor of atrial fibrillation, independent of left ventricular hypertrophy [12]. Although male sex and diabetes mellitus were more common in the AF group in our study, these associations did not reach statistical significance, which aligns with findings from Kirchhof et al., who noted that while diabetes and male sex are recognized risk factors, their impact is often attenuated in smaller sample sizes [13].

Our results also showed significantly larger left atrial diameter and volume index in AF patients, reflecting structural remodeling. This observation is in agreement with the findings of Abhayaratna et al., who emphasized that LA volume is a superior predictor of AF compared to diameter alone [14]. In addition, elevated E/e′ ratio in our AF group suggests increased filling pressures and diastolic dysfunction, which correlates with the study by Tsao et al., who demonstrated a strong association between elevated LV filling pressure and new-onset AF [15]. Although LVEF and LV mass index were slightly higher in AF patients, the differences were not statistically significant, paralleling the results of Vaziri et al., who found that systolic function is less relevant to AF prediction than diastolic parameters and atrial indices [16].

Importantly, left atrial strain analysis in our study revealed markedly impaired reservoir, conduit, and contractile strains in AF patients. This finding is strongly supported by research from Cameli et al., who showed that LA strain indices are highly sensitive markers of atrial dysfunction and superior to conventional echocardiographic parameters in predicting AF [17]. Pathak et al. also reported that reduced reservoir strain was independently associated with higher AF burden and recurrence after ablation [18]. ROC curve analysis in our study further confirmed that reservoir strain had the highest predictive accuracy, which concurs with results from Morris et al., who highlighted LA reservoir strain as a robust predictor of AF development [19].

Multivariate regression analysis in our study identified duration of hypertension, LA volume index, and reduced LA reservoir strain as independent predictors of AF. These findings are consistent with the observations of Shaikh et al., who emphasized that both structural remodeling (LA size) and functional impairment (strain reduction) contribute synergistically to AF risk [20]. Collectively, our results reinforce the emerging consensus that atrial strain, particularly reservoir strain, represents a sensitive and clinically valuable biomarker for early identification of patients at risk of atrial fibrillation.

In this study, older age and longer duration of hypertension were associated with the development of atrial fibrillation. Structural remodeling, reflected by increased left atrial size and volume, along with functional impairment demonstrated by reduced left atrial strain indices, particularly reservoir strain, were strong predictors of AF. Left atrial strain assessment via echocardiography provides a sensitive, non-invasive tool for early identification of patients at high risk of atrial fibrillation, potentially enabling timely preventive strategies and better clinical management.

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