Assessment of the Left Ventricular Diastolic Function and Its Association with the Left Atrial Pressure in Patients with Atrial Fibrillation

Role of cardiac imaging in management of heart failure

The significant advancement in cardiac imaging in recent years led to improved diagnostic accuracy in identifying the specific causes of heart failure and also provided physicians with guidelines for appropriately managing patients with heart failure. Diseases that were once considered rare are now more easily detected with the aid of cardiac imaging. Various cardiac imaging techniques are used to evaluate patients with heart failure, and each technique plays a distinct yet complementary role. This review aimed to discuss the comprehensive role of different types of cardiac imaging in the management of heart failure.

Atrial Cardiomyopathy with Impaired Functional Reserve in Patients with Paroxysmal Atrial Fibrillation

BACKGROUND

Impaired atrial functional reserve during exercise may represent an early stage of atrial cardiomyopathy. To test this hypothesis, the authors evaluated left atrial (LA) and left ventricular (LV) function reserve during exercise in patients with paroxysmal atrial fibrillation (PAF).

METHODS

Sixty-one patients with PAF undergoing radiofrequency catheter ablation and 38 healthy control subjects were prospectively enrolled. LV global longitudinal strain and LA reservoir strain (RS) were measured at rest and during supine bicycle exercise. To identify the early stage of atrial cardiomyopathy without LA structural remodeling, patients with PAF were divided into two groups according to LA volume index (LAVI): atrial fibrillation (AF) group 1 (LAVI ≥ 34 mL/m²) and AF group 2 (LAVI < 34 mL/m²).

RESULTS

LV ejection fraction and global longitudinal strain did not differ between patients with AF and control subjects. LAVI and LA RS did not differ between AF group 2 and control subjects. During exercise, LV global longitudinal strain improved in all groups. Increases in LA RS were attenuated in both AF groups, which also exhibited lower LA functional reserve index than the control subjects. Although resting LA RS was similar between AF group 2 and control subjects, LA functional reserve index was significantly lower in AF group 2. LA functional reserve index was associated with risk for AF recurrence (hazard ratio, 0.852; 95% CI, 0.736-0.988).

CONCLUSIONS

Atrial cardiomyopathy can be anticipated by impaired LA functional reserve during exercise in patients with AF, even in those with normal-sized left atria. Atrial cardiomyopathy occurs independently of changes in LV function and is associated with the recurrence of AF in patients with PAF after radiofrequency catheter ablation.

The cross-section of routine practice of echocardiographic diastolic evaluation in atrial fibrillation in a community hospital: A quality improvement project

BACKGROUND

The echocardiographic assessment of diastolic function in the context of atrial fibrillation (AF) has been controversial and can be challenging and labor-intensive. We aimed to assess the actual practice of diastolic evaluation in AF in our community hospital echocardiography laboratory and to improve clinical performance by a quality improvement project.

METHODS

We reviewed 244 echocardiograms in patients with AF at the time of echocardiography from November 2019 to November 2020 (pre-intervention phase). We classified cases into a complete versus incomplete evaluation group according to the completeness of diastolic parameter measurement. After an educational intervention, we reviewed 68 echocardiograms in patients with AF from August 2021 to October 2021 (post-intervention phase).

RESULTS

Our results demonstrated an improvement in a complete diastolic assessment from 69% to 91% after intervention (p < .001). In the pre-intervention phase, the four parameters (mitral inflow pulsed wave Doppler image, left atrium volume index, mitral annular tissue Doppler image [TDI], and tricuspid regurgitation Vmax), mitral annular TDI was not acquired in 71 out of 244 cases (29.1%) and those cases were classified as incomplete evaluation group. Interestingly, in the pre-intervention phase, 57 out of 162 cases (35%) with preserved EF (≥50%) received significantly more incomplete diastolic evaluation than 14 out of 82 patients (17%) with reduced EF (<50%) (p = .004). There were no statistically significant differences in age, BMI, the reason for requesting echocardiography, and patient level of care between the complete and incomplete evaluation groups. In the post-intervention phase, completeness of diastolic measurement in AF was significantly improved compared to the pre-intervention phase (29% vs. 9%, p < .001, respectively).

CONCLUSION

A quality improvement project effectively improved the clinical performance of diastolic evaluation in AF in our community echocardiography laboratory. After the intervention, we decreased an incomplete evaluation from 30% to 9%. More efforts should be needed to increase awareness and familiarity in evaluating diastolic function in AF.

Impact of atrial fibrillation on left atrium haemodynamics: A computational fluid dynamics study

We analyse the haemodynamics of the left atrium, highlighting differences between healthy individuals and patients affected by atrial fibrillation. The computational study is based on patient-specific geometries of the left atria to simulate blood flow dynamics. We design a novel procedure to compute the boundary data for the 3D haemodynamic simulations, which are particularly useful in absence of data from clinical measurements. With this aim, we introduce a parametric definition of atrial displacement, and we use a closed-loop lumped parameter model of the whole cardiovascular circulation conveniently tuned on the basis of the patient's characteristics. We evaluate several fluid dynamics indicators for atrial haemodynamics, validating our numerical results in terms of clinical measurements; we investigate the impact of geometric and clinical characteristics on the risk of thrombosis. To highlight the correlation of thrombus formation with atrial fibrillation, according to medical evidence, we propose a novel indicator: age stasis. It arises from the combination of Eulerian and Lagrangian quantities. This indicator identifies regions where slow flow cannot properly rinse the chamber, accumulating stale blood particles, and creating optimal conditions for clots formation.

Heart Failure and Atrial Fibrillation: Diastolic Function Differences Depending on Left Ventricle Ejection Fraction

Background: Heart failure (HF) and atrial fibrillation (AF) are prevalent cardiovascular diseases, and their association is common. Diastolic dysfunction may be present in patients with AF and all types of HF, leading to elevated intracardiac pressures. The objective of this study was to analyze diastolic dysfunction in patients with HF and AF depending on left ventricle ejection fraction (LVEF). Material and methods: This prospective study included 324 patients with chronic HF and AF (paroxysmal, persistent, or permanent) hospitalized between January 2018 and March 2021. The inclusion criteria were age older than 18 years, diagnosis of chronic HF and AF, and available echocardiographic data. The exclusion criteria were a suboptimal echocardiographic view, other cardiac rhythms than AF, congenital heart disease, or coronavirus 2 infection. Patients were divided into three subgroups according to LVEF: subgroup 1 included 203 patients with HF with reduced ejection fraction (HFrEF) and AF (62.65%), subgroup 2 included 42 patients with HF with mildly reduced ejection fraction (HFmrEF) and AF (12.96%), and subgroup 3 included 79 patients with HF with preserved ejection fraction (HFpEF) and AF (24.38%). We performed 2D transthoracic echocardiography in all patients. Statistical analysis was performed using R software. Results: The E/e' ratio (p = 0.0352, OR 1.9) and left atrial volume index (56.4 mL/m2 vs. 53.6 mL/m2) were higher in patients with HFrEF than in those with HFpEF. Conclusions: Patients with HFrEF and AF had more severe diastolic dysfunction and higher left ventricular filling pressures than those with HFpEF and AF.

Pathophysiology of Heart Failure with Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is a major public health problem that affects half of all patients with HF. It is rising in prevalence, is associated with high morbidity and mortality, and has very few effective treatments. HFpEF is currently understood as a heterogeneous syndrome originating from the interplay of cardiac and extracardiac abnormalities. The most important pathophysiology in patients with HFpEF is diastolic dysfunction, which presents with impairments in relaxation or increases in chamber stiffness that lead to an increase in left ventricular filling pressures at rest or during exercise that causes dyspnea.