Focal impulse and rotor modulation of atrial rotors during atrial fibrillation leads to organization of left atrial activation as reflected by waveform morphology recurrence quantification analysis and organizational index.

BACKGROUND: Focal impulse and rotor modulation (FIRM) can cause slowing, organization, and occasionally termination of atrial fibrillation (AF), although results have been mixed. To further characterize changes in AF during rotor ablation, we quantified morphologic and temporal activation changes following FIRM. METHODS: In patients undergoing FIRM ablation for AF, we retrospectively analyzed coronary sinus bipolar EGMs before and after rotor ablation, including EGM activation frequency and regularity, dominant frequency (DF), and organizational index (OI). Changes in EGM waveform morphology were determined with recurrence quantification analysis (RQA) consisting of recurrence rate (RR), determinism (DET), laminarity (LAM), average diagonal line length (L), and trapping time (TT) using Wilcoxon signed-rank testing. RESULTS: Overall, 36 rotors from 21 patients undergoing FIRM ablation were analyzed. All morphology RQA parameters demonstrated significant organization of atrial activation after rotor ablation (RR P = .03, DET P = .005, LAM P = .03, L P = .005, TT P = .009). The organizational index also showed a significant increase after rotor ablation (P = .01), and the change in OI correlated with changes in all morphology parameters. Of the rotors, 14/36 (39%) rotors showed organizational changes in all morphology parameters and OI, and an additional 5 rotors (19/36, 53%) showed organizational changes in 4 of 5 morphology parameters and OI. CONCLUSIONS: Coronary sinus EGM waveform morphologies and activation patterns are significantly altered after FIRM ablation even when there is no fibrillatory slowing. RQA morphology analysis and organizational index may impart important information regarding underlying AF organization and may be useful in quantifying the acute response to ablation.

The Prognostic Value of Diastolic and Systolic Mechanical Left Ventricular Dyssynchrony Among Patients With Coronary Heart Disease.

OBJECTIVES: The goal of this study was to examine whether diastolic dyssynchrony, measured by using gated single-photon emission computed tomography (GSPECT) myocardial perfusion imaging (MPI) in patients with coronary artery disease (CAD), is independently associated with adverse outcomes. BACKGROUND: Systolic left ventricular dyssynchrony is known to be associated with worse clinical outcome in patients with CAD. METHODS: This study included patients who presented to Duke University for GSPECT MPI between 2003 and 2009. Patients had at least 1 major epicardial obstruction ≥50%. Dyssynchrony was assessed by using Emory Cardiac Toolbox software and compared with a control population without CAD. Abnormal degree of diastolic/systolic dyssynchrony was defined as values above 2 SDs above mean of mechanical dyssynchrony parameters. Using Cox proportional hazards modeling, the adjusted association between dyssynchrony and outcomes, including all-cause and cardiovascular death, was assessed. RESULTS: Among 1,310 patients with a median age of 64 years (interquartile range: 55 to 72 years), 69.7% were male and 2.6% had left bundle branch block. Overall, 241 (18.4%) and 238 (18.2%) patients had significant systolic and diastolic mechanical dyssynchrony, respectively, and 211 (16.1%) had both. After a median follow-up of 7.1 years, 543 deaths occurred. At 5 years, the mortality estimate was 21.2% among patients with a normal degree of diastolic left ventricular mechanical dyssynchrony (LVMD) and 41.7% among those with an abnormal degree of LVMD (p < 0.001). When added to clinical comorbidities, electrical dyssynchrony, and systolic LVMD, diastolic dyssynchrony was incrementally associated with cardiovascular mortality (global chi-square statistic of 211.9 vs. 222.8; 2 degrees of freedom; p = 0.004). In a model that also includes left ventricular ejection fraction, the addition of diastolic dyssynchrony to systolic dyssynchrony maintained an incremental prognostic benefit (global chi-square statistic of 234.8 vs. 241.8; p = 0.030). Adjustment for baseline ischemia and scar burden did not change this relationship. CONCLUSIONS: Systolic and diastolic left ventricular dyssynchrony, as measured by using GSPECT MPI, were associated with adverse outcomes. Moreover, diastolic dyssynchrony appears to provide incremental predictive value to clinical history, electrical dyssynchrony, and left ventricular function.

Mineralocorticoid Receptor Antagonism in Patients With Atrial Fibrillation: Findings From the ORBIT-AF (Outcomes Registry for Better Informed Treatment of Atrial Fibrillation) Registry.

BACKGROUND: Mineralocorticoid receptor antagonist (MRA) therapy may be beneficial to patients with atrial fibrillation (AF), but little is known about their use in patients with AF and subsequent outcomes. METHODS AND RESULTS: In order to better understand MRA use and subsequent outcomes, we performed a retrospective cohort study of the contemporary ORBIT-AF (Outcomes Registry for Better Informed Treatment of Atrial Fibrillation) registry. AF progression and cardiovascular outcomes were compared using propensity-matched Cox proportional hazards modeling according to MRA use at baseline and new MRA use at follow-up versus patients with no MRA use. Among 7012 patients with nonpermanent AF, 320 patients were taking MRA at enrollment, and 416 patients initiated MRA use during follow-up. The mean patient age was 72.5 years, 56.3% were men, and 70.4% had paroxysmal AF. Among all patients taking MRAs, 434 (59.0%) had heart failure, 655 (89.0%) had hypertension, and 380 (51.6%) had both. After adjustment, new MRA use was not associated with reduced AF progression (hazard ratio, 1.18; 95% confidence interval, 0.88-1.58; P=0.27) but showed a trend towards lower risk of stroke, transient ischemic attack, or systemic embolism (hazard ratio, 0.17; 95% confidence interval, 0.02-1.23; P=0.08). Results were similar for a comparison of new MRA users and baseline MRA users compared with nonusers. CONCLUSIONS: In community-based outpatients with AF, the majority of MRA use was for heart failure and hypertension. MRA use also trended towards lower adjusted stroke risk. Future studies should test the hypothesis that MRA use may decrease the risk of stroke in patients with AF.

Raising the pressure: Hemodynamic effects of splanchnic nerve stimulation.

A number of cardiovascular and neurological diseases are characterized by a dysregulation of intravascular volume distribution. The veins and arteries of the visceral organs form the so-called splanchnic vascular compartment and are the largest reservoir for intravascular blood. The blood localized in the splanchnic compartment can be mobilized in and out of the compartment via passive compression or active neurohormonal recruitment. We studied the hemodynamic effects of splanchnic nerve stimulation during five cases of irreversible electroporation (IRE) in patients with pancreatic cancer. In IRE, repeated bursts of high-voltage electrical fields are applied to visceral beds for >1 min, which induces rapid increase in blood pressure, heart rate, and cardiac output. We present the first analysis into the hemodynamic changes with splanchnic nerve stimulation and explore potential mechanisms of the hyperdynamic state. Our analysis presents the first human report of splanchnic nerve stimulation to induce hypertension and volume redistribution, introducing the splanchnic nerves as a key component of cardiovascular regulation.NEW & NOTEWORTHY Our case series provides the first detailed description of human hemodynamic effects with splanchnic nerve stimulation. Splanchnic nerve stimulation results in profound hemodynamic alteration with rapid onset of hypertension and blood mobilization.