Valvular Heart Disease
Transient, Subclinical Atrial Fibrillation and Risk of Systemic Embolism in Patients With Rheumatic Mitral Stenosis in Sinus Rhythm

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Highlights

  • Rheumatic MS is a common cause of stroke and systemic embolism in developing countries.

  • Although most patients who experience strokes are in AF, about 1/5 are in sinus rhythm. There is little information on the risk for and predictors of stroke and systemic embolism in these patients.

  • This prospective study suggests that in symptomatic patients with rheumatic MS who are in sinus rhythm, the risk for stroke or systemic embolism is high.

  • The presence of transient (<30 seconds), subclinical runs of AF detected on 24-hour Holter monitoring is a strong predictor of the occurrence of stroke or systemic embolism.

  • The presence of subclinical AF on Holter monitoring in patients with MS in sinus rhythm may help in the risk stratification of these patients for stroke and systemic embolism.

Stroke and systemic embolism occur frequently in patients with rheumatic mitral stenosis (MS) in sinus rhythm (SR), but the risk and predictors of embolic events in this population are not well studied. The aim of this study was to determine if transient, subclinical atrial fibrillation (AF) increases the risk of systemic embolism in patients with MS in SR. A single-center, prospective observational study of patients with rheumatic MS in SR was performed. The rate of the composite primary outcome of stroke, transient ischemic attack, or non–central nervous system embolism was determined, as well as the predictive value of Holter-detected episodes of transient (<30 seconds), subclinical AF for this outcome. Hazard ratios were derived for subclinical AF, after adjustment for clinical and echocardiographic predictors of systemic embolism, using Cox regression. The sensitivity, specificity, and area under the receiver-operating characteristic curve of subclinical AF were determined for the primary outcome. Among 179 patients (mean follow-up 10.2 months), the rate of the primary outcome was 5.3/100 patient-years (95% confidence interval [CI] 2.6 to 10.5). In univariate analysis, subclinical AF (hazard ratio 4.54, 95% CI 1.08 to 19.0, p = 0.038) and dense spontaneous echocardiographic contrast (hazard ratio 4.32, 95% CI 1.03 to 18.09, p = 0.045) were predictors of the primary outcome. In multivariate analysis, subclinical AF remained the only significant predictor (hazard ratio 5.02, 95% CI 1.15 to 22.0, p = 0.032). Subclinical AF had an area under the receiver-operating characteristic curve of 0.68 and high negative predictive value (97.7%) for the primary outcome. In conclusion, Holter-detected, transient (<30 seconds), subclinical AF is a predictor of stroke and systemic embolism in patients with rheumatic MS in SR. Considering the high risk for embolism, randomized trials of oral anticoagulation are needed in this population.

Section snippets

Methods

This was a single-center, prospective, observational study of patients with pure or dominant rheumatic MS in SR. Patients attending the cardiology outpatient clinics at a tertiary care teaching hospital were assessed for eligibility. Patients were approached for enrollment if they were ≥18 years of age and had rheumatic MS (mitral valve area [MVA] <2 cm2 on echocardiography) as an isolated or dominant lesion and were in SR. In patients with multivalve disease, MS was considered dominant if it

Results

From January to December 2012, we screened 256 patients with clinically diagnosed MS for possible enrollment. We excluded 23 patients after initial evaluation and echocardiography (Figure 1). At the screening interview, 54 of the remaining 233 eligible patients indicated their inability or reluctance to attend follow-up visits or undergo baseline Holter examinations. The remaining 179 patients were enrolled in the present study. Patients were young (mean age 32 years) and had on average been

Discussion

In this cohort of young patients with rheumatic MS in SR, we found a high rate of stroke, TIA, or non-CNS systemic embolism. Transient (<30 seconds), subclinical AF was observed on 24-hour Holter monitoring in 1/4th of these patients. After adjustment for parameters of disease severity and stasis in the left atrium, subclinical AF was associated with a fivefold increase in the risk for the primary outcome. Patients without subclinical AF had a high likelihood of freedom from systemic embolic

Disclosures

The authors have no conflicts of interest to disclose.

References (16)

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