Yogeswaran, Vidhushei

AbstractBackgroundPulmonary vein isolation (PVI) with autonomic modulation may be more successful than PVI alone for atrial fibrillation (AF) ablation and may be signaled by changes in sinus rhythm heart rate (HR) post ablation. We sought to determine if a change in sinus rhythm HR predicted AF recurrence post PVI.MethodsPatients who underwent AF ablation from 2000 to 2011 were included if sinus rhythm was noted on ECG within 90 days pre and 7 days post ablation. Basic ECG interval and HR changes were analyzed and outcomes determined.ResultsA total of 1152 patients were identified (74.3% male, mean age 57 ± 11 years). Mean AF duration was 5.2 ± 5.3 years. Paroxysmal AF was noted in 712 (61.8%) of the patients. Mean EF was 61% ± 6%. Sinus rhythm HR was 61 ± 11 pre‐ablation and 76 ± 13 bpm post‐ablation (27% ± 24% increase, p < .001). The ability of relative HR change post‐ablation to predict AF recurrence was borderline (hazard ratio 0.65 [0.41–1.01], p = .067). With patients separated into quartiles based on the relative HR change, the upper quartile with the largest relative increase in HR had a significantly lower rate of AF recurrence compared to the lowest quartile following multi variable modeling (p = .038). There were significant changes in PR (171 ± 28 to 167 ± 30 ms) and QTc (424 ± 25 to 434 ± 29 ms) intervals (both p < .001) but these were not predictive of outcome.ConclusionRelative changes in HR post AF ablation correlates with AF recurrence. Further prospective studies are needed to confirm this relationship.

Background: Right ventricular systolic dysfunction (RVD) often coexists with various cardiopulmonary diseases. However, the association between RVD and risk of sudden cardiac death (SCD) has not been well studied. This study examined the risk of SCD associated with RVD in patients with heterogeneous underlying cardiac diseases. Methods: The Mayo Clinic cardiac care unit database included 5463 consecutive patients with complete echocardiographic evaluation to assess right ventricular systolic function and RVD severity. Prospective surveillance follow-up was obtained for all patients. SCD was adjudicated when a malignant ventricular arrhythmia was documented as the primary rhythm leading to death. RESULTS: The prevalence of mild RVD and moderate-severe RVD was 14.9% and 17.1%, respectively. Patients with RVD were more likely to have a history of congestive heart failure, cardiac arrest, pulmonary disease, and lower baseline left ventricular ejection fraction compared with those with normal right ventricular systolic function. During a median follow-up of 14 months, the incidence of SCD was highest in patients with moderate-severe RVD (7.4% versus 4.4% in mild RVD versus 1.6% in normal right ventricular function; P <0.001). After adjustment for baseline characteristics, mild RVD (adjusted hazard ratio, 1.57; P =0.046) and moderate-severe RVD (adjusted hazard ratio, 1.91; P =0.006) were independently associated with an increased risk of SCD. Moderate-severe RVD remained an independent predictor of SCD for patients with left ventricular ejection fraction >35% without or with preexisting implantable cardioverter-defibrillator (adjusted hazard ratio, 4.12; P =0.003 and adjusted hazard ratio, 5.04; P <0.001, respectively). Conclusions: Presence of RVD in patients with a history of preexisting cardiac disease is an independent predictor of SCD irrespective of left ventricular ejection fraction.

Endovascular Stimulation for Treatment of HypotensionBackgroundWe have previously shown that sympathetic ganglia stimulation via the renal vein rapidly increases blood pressure. This study further investigated the optimal target sites and effective energy levels for stimulation of the renal vasculatures and nearby sympathetic ganglia for rapid increase in blood pressure.MethodsThe pre‐study protocol for endovascular stimulations included 2 minutes of stimulation (1–150 V and 10 pulses per second) and at least 2 minutes of rest during poststimulation. If blood pressure and/or heart rate were changed during the stimulation, time to return to baseline was allowed prior to the next stimulation.ResultsIn 11 acute canine studies, we performed 85 renal artery, 30 renal vein, and 8 hepatic vasculature stimulations. The mean arterial pressure (MAP) rapidly increased during stimulation of renal artery (95 ± 18 mmHg vs. 103 ± 15 mmHg; P < 0.0001), renal vein (90 ± 16 mmHg vs. 102 ± 20 mmHg; P = 0.001), and hepatic vasculatures (74 ± 8 mmHg vs. 82 ± 11 mmHg; P = 0.04). Predictors of a significant increase in MAP were energy >10 V focused on the left renal artery, bilateral renal arteries, and bilateral renal veins (especially the mid segment). Overall, heart rate was unchanged, but muscle fasciculation was observed in 22.0% with an output >10 V (range 15–150 V). Analysis after excluding the stimulations that resulted in fasciculation yielded similar results to the main findings.ConclusionsStimulation of intra‐abdominal vasculatures promptly increased the MAP and thus may be a potential treatment option for hypotension in autonomic disorders. Predictors of optimal stimulation include energy delivery and the site of stimulation (for the renal vasculatures), which informs the design of subsequent research.