Left Atrial Fractional Shortening: A Simple and Practical "Strain" for Everyone

Incidence, Risk Factors, and Outcomes of Left Atrial Enlargement in Patients Requiring Right Ventricular Pacing: A Retrospective Study of 461 Cases from 2012 to 2020

BACKGROUND Long-term right ventricular (RV) pacing has been linked to left atrial enlargement (LAE). The incidence and risk factors associated with significant LAE after RV pacing remain unknown. This retrospective study included 461 patients requiring RV pacing at 2 centers between 2012 and 2020 and aimed to evaluate the incidence, risk factors, outcomes, and complications of LAE. MATERIAL AND METHODS A total of 461 patients with normal-sized pre-implant left atrial dimension and dual-chamber pacing pacemaker implantation for complete atrioventricular block were enrolled. Patients were grouped based on a ≥20% increase from their baseline left atrial dimension by echocardiography, indicating significant LAE, and initial characteristics, echocardiographic data, and outcomes were compared. RESULTS During a mean 7.0±4.9 years follow-up period, 96 patients (20.8%) developed significant LAE, whereas 365 patients did not. In multivariate logistic regression analysis, smaller pre-implant left atrial dimension (OR, 0.776; 95% CI, 0.728-0.828; P<0.001), lower post-implant left ventricular ejection fraction (OR, 0.976; 95% CI, 0.957-0.995; P=0.014), post-implant development of moderate to severe mitral regurgitation (OR, 2.357; 95% CI, 1.172-4.740; P=0.016), and RV pacing duration ≥3.3 years (OR, 1.576; 95% CI, 1.039-2.646; P=0.045) were independent predictors of significant LAE after RV-dependent pacing. There was a significant difference in the incident stroke events between patients without and with significant LAE (9.9% vs 17.7%; log-rank P=0.047). CONCLUSIONS Long-term RV pacing was linked to significant LAE in 20.8% of patients with complete atrioventricular block, with those affected experiencing a higher stroke rate during follow-up.

Predictive Value of Left Atrial and Ventricular Strain for the Detection of Atrial Fibrillation in Patients With Cryptogenic Stroke

Background and Aims

Cryptogenic stroke (CS) is associated with a high rate of recurrences and adverse outcomes at long-term follow-up, especially due to its unknown etiology that often leads to ineffective secondary prevention. Asymptomatic atrial fibrillation (AF) could play an important pathophysiological role. Some studies have pointed to left atrial (LA) and left ventricular (LV) systolic and diastolic dysfunction as surrogate markers of AF. The aim of the study is to evaluate the relationship between echocardiographic parameters of LA and LV function, and the occurrence of AF revealed by continuous ECG monitoring in a cohort of patients with CS.

Methods

Single-center prospective cohort study. Seventy-two patients with CS with insertable cardiac monitors (ICM) underwent transthoracic echocardiography (TTE). TTE was focused on LA and LV function, including both standard and longitudinal strain-derived parameters. All detected AF episodes lasting more than 2 min were considered.

Results

Continuous ECG monitoring revealed subclinical AF in 23 patients (32%) at an average of 6.5 months after ICM implantation. Many echocardiographic parameters, indicating LA volume and LV systolic/diastolic function, were significantly associated with the occurrence of AF, suggesting the worst atrial function in the AF group. Furthermore, multivariable regression analysis revealed that peak atrial contraction strain and left ventricular strain were independently associated with AF (adjusted OR = 0.72, CI 95% 0.48–0.90, p = 0.005, and adjusted OR = 0.69, CI 95% 0.46–0.95, p = 0.041, respectively).

Conclusion

In patients with CS, LA and LV strain analysis add predictive value for the occurrence of AF over clinical and morpho-functional echocardiographic parameters. Impaired booster pump strain and LV longitudinal strain are strong and independent predictors of AF.

Can echocardiography improve the prediction of thromboembolic risk in atrial fibrillation? Evidences and perspectives

Atrial fibrillation is the most common arrhythmia and its prevalence is expected to further increase. Patients with atrial fibrillation have an increased risk of stroke (fivefold increased risk), heart failure, and death. In patients with non-valvular atrial fibrillation, the most recent guidelines recommend the use of the CHA₂DS₂-VASc (congestive heart failure, arterial hypertension, age > 75 years, diabetes mellitus, stroke/transient ischemic attack, vascular disease, age 65-74 years, sex category) scoring system to identify those who may benefit from oral anticoagulant treatment. Guidelines recommend initiation of oral anticoagulation with vitamin K antagonists or direct oral anticoagulants in men with a score ≥ 2 and in women with a score ≥ 3, while oral anticoagulation in individuals with a score of 0 is not recommended. Accordingly, men with CHA₂DS₂VASc score = 1 (and women with CHA₂DS₂VASc = 2) represent a grey zone where guidelines do not provide a definite oral anticoagulant indication. Implementation of risk stratification with transthoracic echocardiography could be extremely useful. Both prospective and observational studies using transthoracic echocardiography prediction of events and studies utilizing transesophageal echocardiographic parameters as surrogate markers of thromboembolic events make sustainable the hypothesis that echocardiography could improve thromboembolism prediction in non-valvular atrial fibrillation. However, because of some controversial results of different studies, determination of the best echocardiographic parameter predicting thromboembolic events in atrial fibrillation remains uncertain. The combination of left atrial enlargement with left atrial function (in particular assessing left atrial strain) appears to be very valuable, but needs to be confirmed in large-scale multi-center trials.