Kavitha Damal

Atrial Fibrillation Ablation Outcome Is Predicted by Left Atrial Remodeling on MRI

Background—Although catheter ablation therapy for atrial fibrillation (AF) is becoming more common, results vary widely, and patient selection criteria remain poorly defined. We hypothesized that late gadolinium enhancement MRI (LGE-MRI) can identify left atrial (LA) wall structural remodeling (SRM) and stratify patients who are likely or not to benefit from ablation therapy. Methods and Results—LGE-MRI was performed on 426 consecutive patients with AF without contraindications to MRI before undergoing their first ablation procedure and on 21 non-AF control subjects. Patients were categorized by SRM stage (I–IV) based on the percentage of LA wall enhancement for correlation with procedure outcomes. Histological validation of SRM was performed comparing LGE-MRI with surgical biopsy. A total of 386 patients (91%) with adequate LGE-MRI scans were included in the study. After ablation, 123 patients (31.9%) experienced recurrent atrial arrhythmias during the 1-year follow-up. Recurrent arrhythmias (failed ablations) occurred at higher SRM stages with 28 of 133 (21.0%) in stage I, 40 of 140 (29.3%) in stage II, 24 of 71 (33.8%) in stage III, and 30 of 42 (71.4%) in stage IV. In multivariate analysis, ablation outcome was best predicted by advanced SRM stage (hazard ratio, 4.89; P<0.0001) and diabetes mellitus (hazard ratio, 1.64; P=0.036), whereas increased LA volume and persistent AF were not significant predictors. LA wall enhancement was significantly greater in patients with AF versus non-AF controls (16.6±11.2% versus 3.1±1.9%; P<0.0001). Histological evidence of remodeling from surgical biopsy specimens correlated with SRM on LGE-MRI. Conclusions—Atrial SRM is identified on LGE-MRI, and extensive LGE (≥30% LA wall enhancement) predicts poor response to catheter ablation therapy for AF.

Higher Degree of Left Atrial Structural Remodeling in Patients with Atrial Fibrillation and Left Ventricular Systolic Dysfunction

Catheter ablation significantly improves the left ventricular (LV) function in patients with atrial fibrillation (AF) and LV systolic dysfunction. In this study, we compared the degree of left atrial structural remodeling (LA‐SRM) in patients with normal versus reduced LV ejection fraction (LVEF). We also studied the impact of LA‐SRM on LVEF improvement in patients undergoing ablation of AF.

Documentation of delirium in the VA electronic health record

BackgroundDelirium is a life-threatening, clinical syndrome common among the elderly and hospitalized patients. Delirium is under-recognized and misdiagnosed, complicating efforts to study the epidemiology and construct appropriate decision support to improve patient care. This study was primarily conducted to realize how providers documented confirmed cases of delirium in electronic health records as a preliminary step for using computerized methods to identify patients with delirium from electronic health records.MethodsThe Mental Health Consult (MHC) team reported cases of delirium to the study team during a 6-month study period (December 1, 2009 - May 31, 2010). A chart extraction tool was developed to abstract documentation of diagnosis, signs and symptoms and known risk factors of delirium. A nurse practitioner, and a clinical pharmacist independently reviewed clinical notes during each patients hospital stay to determine if delirium and or sign and symptoms of delirium were documented.ResultsThe MHC team reported 25 cases of delirium. When excluding MHC team notes, delirium was documented for 5 of the 25 patients (one reported case in a physician’s note, four in discharge summaries). Delirium was ICD-9 Coded for 7 of the 25 cases. Signs and symptoms associated with delirium were characterized in 8 physician notes, 11 discharge summaries, and 14 nursing notes, accounting for 16 of the 25 cases with identified delirium.ConclusionsDocumentation of delirium is highly inconsistent even with a confirmed diagnosis. Hence, efforts to use existing data to precisely estimate the prevalence of delirium or to conduct epidemiological studies based on medical records will be challenging.

Relationship between left atrial tissue structural remodelling detected using late gadolinium enhancement MRI and left ventricular hypertrophy in patients with atrial fibrillation

AIMS Therapeutic effectiveness of ablation of atrial fibrillation (AF) is related to cardiovascular comorbidities. We studied the relationship between left ventricular hypertrophy (LVH) and left atrial tissue structural remodelling (LA-SRM), in patients presenting for AF ablation. METHODS AND RESULTS We identified 404 AF patients who received a late gadolinium enhancement magnetic resonance imaging (LGE-MRI) prior to catheter ablation. Left ventricular hypertrophy was defined as LV mass index >116 g/m(2) in men and >104 g/m(2) in women. One hundred and twenty-two patients were classified as the LVH group and 282 as the non-LVH group. We stratified patients into four stages based on their degree of LA-SRM (minimal, <5% fibrosis; mild, >5-20%; moderate, >20-35%; and extensive, >35%). All patients underwent catheter ablation with pulmonary vein isolation and posterior wall and septal debulking. The procedural outcome was monitored over a 1-year follow-up period. The mean LA-SRM was significantly higher in patients with LVH (19.4 ± 13.2%) than in non-LVH patients (15.3 ± 9.8%; P< 0.01). Patients with LVH generally had extensive LA-SRM (moderate and extensive stages; 38.5% of LVH group) as compared with non-LVH patients (23.1% of non-LVH group; P < 0.01). A Cox regression analysis showed that patients with LVH also had significantly higher AF recurrence rates than non-LVH patients (43.2 vs. 28%; P = 0.008) during the 1-year follow-up period post-ablation. CONCLUSION Patients with LVH tend to have a significantly greater degree of LA-SRM, when compared with patients without LVH. Moreover, LA-SRM is a predictor for procedural success in patients undergoing AF ablation procedure.

The effect of fat pad modification during ablation of atrial fibrillation: late gadolinium enhancement MRI analysis.

Magnetic resonance imaging (MRI) can visualize locations of both the ablation scar on the left atrium (LA) after atrial fibrillation (AF) ablation and epicardial fat pads (FPs) containing ganglionated plexi (GP).

The degree of left atrial structural remodeling impacts left ventricular ejection fraction in patients with atrial fibrillation

OBJECTIVES The extent of left atrial (LA) wall structural remodeling (fibrosis) detected by late gadolinium enhancement-magnetic resonance imaging (LGE-MRI) is correlated with advanced atrial fibrillation (AF). The concomitant occurrence of AF and left ventricular (LV) dysfunction is not uncommon. We studied the effect of LA fibrosis, a confounder of both AF and LV dysfunction, on LV ejection fraction (EF). STUDY DESIGN For the analysis, we identified and included 384 patients from our retrospective AF database who underwent LGE-MRI and transthoracic echocardiography prior to AF ablation. Based on the degree of LA fibrosis, patients were categorized into four stages as: Utah 1 (<5% LA fibrosis), Utah 2 (5-20% fibrosis), Utah 3 (20-35% fibrosis), and Utah 4 (>35% fibrosis). RESULTS The average pre-ablation LVEF was 60.5%±8.5% (n=24) in Utah stage 1 patients, 55.7%±10.3% (n=240) in Utah stage 2 patients, 51.7±11.5% (n=90) in Utah stage 3 patients, and 48.9%±11.6% (n=30) in Utah stage 4 patients (p<0.001, one-way ANOVA). The percentage of LA fibrosis was significantly negatively correlated to LVEF pre-ablation in a univariate analysis (p<0.001). In a multivariate model accounting for age, gender, AF type, and comorbidities such as diabetes and hypertension, Utah stage remained a significant predictor of pre-ablation EF (p<0.001). CONCLUSION Patients with extensive LA fibrosis appear to have depressed LV function pre-ablation, suggesting that structural remodeling in the LA may also be triggering and promoting remodeling within the ventricular myocardium.

A multi-center trial of LGE-MRI of the left atrium

Background Atrial fibrillation (AF) is the most common rhythm disturbance. Radio-frequency ablation (RFA) of the left atrium (LA) is effective for drug refractory AF patients. Outcome of RFA procedure depends on the degree of pre-ablation LA fibrosis and amount of post-ablation scar. Late gadolinium enhancement (LGE) imaging can detect fibrosis and visualize scar. However, only few centers with advanced expertise in cardiac MR (CMR) have demonstrated successful LGE of LA. Multi-center study was initiated to study reproducibility of LGE of LA.

Incidental MRI findings of left ventricular myocardial scar in atrial fibrillation patients is associated with increased stroke risk

Background Left ventricular late gadolinium enhancement (LV-LGE) is a known incidental cardiac magnetic resonance (CMR) finding in atrial fibrillation (AF) patients and has recently been associated with increased mortality [1]. While LV-LGE is an indicator of poor prognosis in patients with cardiomyopathy, data on the clinical significance of incidental findings of LV-LGE in AF patients is still unavailable. We aimed to evaluate the association of this incidental finding to ischemic stroke in atrial fibrillation.

Improved left atrial imaging in atrial fibrillation patients using novel ECG-gated vs. conventional non-gated cardiac MRA

Background In patients undergoing atrial fibrillation (AF) procedures, imaging of the left atrium (LA) and pulmonary veins (PV) is important for pre-ablation planning and to identify post ablation complications. Conventional MRA protocols use first-pass, non-gated sequences that require long breathholds. Quality of non-gated MRA’s can be challenging in sick or sedated patients. We developed a novel ECGgated, respiratory navigated MRA sequence less dependent on patient compliance, which yields better clarity of LA anatomy.

Left atrial late gadolinium enhancement following external beam radiation for lymphoma: a potential model for exploring radiation-related heart disease

We are able to detect subclinical post-irradiation changes to the heart with left atrial late gadolinium enhanced magnetic resonance imaging (LGE-MRI).