Amrish Deshmukh

Left Atrial Transcriptional Changes Associated With Atrial Fibrillation Susceptibility and Persistence

Background—Prior transcriptional studies of atrial fibrillation (AF) have been limited to specific transcripts, animal models, chronic AF, right atria, or small samples. We sought to characterize the left atrial transcriptome in human AF to distinguish changes related to AF susceptibility and persistence. Methods and Results—Left atrial appendages from 239 patients stratified by coronary artery disease, valve disease, and AF history (no history of AF, AF history in sinus rhythm at surgery, and AF history in AF at surgery) were selected for genome-wide mRNA microarray profiling. Transcripts were examined for differential expression with AF phenotype group. Enrichment in differentially expressed genes was examined in 3 gene set collections: a transcription factor collection, defined by shared conserved cis-regulatory motifs, a miRNA collection, defined by shared 3′ untranslated region motifs, and a molecular function collection, defined by shared Gene Ontology molecular function. AF susceptibility was associated with decreased expression of the targets of CREB/ATF family, heat-shock factor 1, ATF6, SRF, and E2F1 transcription factors. Persistent AF activity was associated with decreased expression in genes and gene sets related to ion channel function consistent with reported functional changes. Conclusions—AF susceptibility was associated with decreased expression of targets of several transcription factors related to inflammation, oxidation, and cellular stress responses. In contrast, changes in ion channel expression were associated with AF activity but were limited in AF susceptibility. Our results suggest that significant transcriptional remodeling marks susceptibility to AF, whereas remodeling of ion channel expression occurs later in the progression or as a consequence of AF.

Impact of race and gender on clinical outcomes of catheter ablation in patients with atrial fibrillation

Radiofrequency catheter ablation (CA) is an effective treatment of drug‐refractory atrial fibrillation (AF). However, the efficacy of CA by race and gender has not been well characterized. We sought to determine the impact of ethnicity and gender on clinical outcome following CA in patients with AF.

Atrial Arrhythmias and Electroanatomical Remodeling in Patients With Left Ventricular Assist Devices

Background The incidence, predictors, and impact of atrial arrhythmias along with left atrial structural changes in patients with left ventricular assist devices (LVADs) remain undetermined. Methods and Results All patients who underwent LVAD implantation from 2008 to 2015 at the University of Chicago Medical Center were included. Electronic medical records, electrocardiograms, echocardiograms, and cardiac electrical device interrogations were reviewed. The association of arrhythmias and clinical covariates with survival was evaluated by Kaplan–Meier and Cox proportional hazards analyses. A total of 331 patients were followed for a median of 330 days (range 0–2306 days). Mean age was 57.8±12.8 years, 256 participants (77.3%) were male, mean left ventricular ejection fraction was 20±6.6%, and 124 (37.5%) had ischemic cardiomyopathy. Atrial arrhythmias (53.8%) were highly prevalent and frequently coexisted before LVAD implantation: atrial fibrillation (AF) in 45.9%, atrial flutter in 13.9%, atrial tachycardia in 6.9%, and atrioventricular nodal reentrant tachycardia in 1.2%. New‐onset AF was documented in 14 patients (7.8% of patients without prior AF) after the first 30 days with an LVAD. Increasing age, renal insufficiency, and lung disease were predictors of new‐onset AF after LVAD implantation. Of patients with paroxysmal AF, 43% had no further AF after LVAD. Left atrial size and volume index improved with LVAD (P<0.005). History of persistent AF, atrial tachycardia, ventricular arrhythmia, coronary artery bypass, and low albumin were associated with decreased survival. Conclusions Atrial arrhythmias are significantly prevalent in patients who require LVAD and are associated with increased mortality; however, LVADs induce favorable atrial structural and electrical remodeling.

His bundle pacing: Initial experience and lessons learned

Direct His bundle pacing provides the most physiologic means of artificial pacing of the ventricles with a preserved His-Purkinje system and may play a role in patients with a diseased intrinsic conduction system. We describe our initial motivations and experience with permanent direct His bundle pacing and important lessons learned since that time.

Impact of high-grade atrioventricular block and cumulative frequent pacing on atrial arrhythmias

The relationship between high‐grade atrioventricular block (HGAVB) with cumulative frequent pacing and risk of atrial arrhythmias (AAs) has not been well characterized. We hypothesized HGAVB and pacing may have significant impact on incidence and prevalence of AAs by modulating atrial substrate.

Hemodynamics of His Bundle Pacing

In addition to the His bundle, numerous other sites have been evaluated as more physiologic alternatives to pacing at the right ventricular apex. Several hemodynamic studies have shown the benefit of His bundle pacing and septal pacing in comparison with right ventricular apical pacing. This article summarizes this literature and presents acute hemodynamic data in an intrapatient study examining His bundle pacing, right ventricular septal pacing, and right ventricular apical pacing.

INCIDENCE, PREDICTORS, AND OUTCOME OF POSTOPERATIVE ATRIAL FIBRILLATION IN PATIENTS RECEIVING CONTINUOUS FLOW LEFT VENTRICULAR ASSIST DEVICES

Background: Postoperative atrial fibrillation (POAF) is associated with increased mortality, morbidity, and length of hospital stay after cardiac surgery. However, the incidence, predictors, and clinical outcomes of POAF in patients undergoing implantation of left ventricular assist devices (LVAD)

Symptomatic Long Pauses and Bradycardia due to Massive Multinodular Goiter

Sinus node dysfunction with symptomatic bradycardia or chronotropic incompetence is generally an indication for pacemaker implantation. However, in patients with symptomatic sinus bradycardia, the identification and treatment of underlying pathologies may avoid the need for permanent pacemaker implantation. We present a case of carotid sinus syndrome and severe obstructive sleep apnea due to a massive multinodular goiter in a patient who presented with recurrent sinus pauses and syncope. The patient was managed without pacemaker implantation but instead with thyroidectomy resulting in decompression of the carotid sinus and airway and resolution of bradycardic episodes.