Shailesh Male

Low-level transcutaneous electrical stimulation of the auricular branch of the vagus nerve: A noninvasive approach to treat the initial phase of atrial fibrillation

BACKGROUND We studied the effects of transcutaneous electrical stimulation at the tragus, the anterior protuberance of the outer ear, for inhibiting atrial fibrillation (AF). OBJECTIVE To develop a noninvasive transcutaneous approach to deliver low-level vagal nerve stimulation to the tragus in order to treat cardiac arrhythmias such as AF. METHODS In 16 pentobarbital anesthetized dogs, multielectrode catheters were attached to pulmonary veins and atria. Three tungsten-coated microelectrodes were inserted into the anterior right ganglionated plexi to record neural activity. Tragus stimulation (20 Hz) in the right ear was accomplished by attaching 2 alligator clips onto the tragus. The voltage slowing the sinus rate or atrioventricular conduction was used as the threshold for setting the low-level tragus stimulation (LL-TS) at 80% below the threshold. At baseline, programmed stimulation determined the effective refractory period (ERP) and the window of vulnerability (WOV), a measure of AF inducibility. For hours 1-3, rapid atrial pacing (RAP) was applied alone, followed by concomitant RAP+LL-TS for hours 4-6 (N = 6). The same parameters were measured during sinus rhythm when RAP stopped after each hour. In 4 other animals, bivagal transection was performed before LL-TS. RESULTS During hours 1-3 of RAP, there was a progressive and significant decrease in ERP, increase in WOV, and increase in neural activity vs baseline (all P < .05). With RAP+LL-TS during hours 4-6, there was a linear return of ERP, WOV, and neural activity toward baseline levels (all P < .05, compared to the third-hour values). In 4 dogs, bivagal transection prevented the reversal of ERP and WOV despite 3 hours of RAP+LL-TS. CONCLUSIONS LL-TS can reverse RAP-induced atrial remodeling and inhibit AF inducibility, suggesting a potential noninvasive treatment of AF.

Cost Burden of Stroke Mimics and Transient Ischemic Attack after Intravenous Tissue Plasminogen Activator Treatment

BACKGROUND Treatment decisions for patients with acute stroke symptoms are based on pertinent history, neurologic examination, laboratory studies, and head computed tomography. In this setting, patients with stroke mimic (SM) may mistakenly receive intravenous tissue plasminogen activator (IV-rtPA). The goal of this study was to investigate the excess direct/indirect hospital costs among patients who received IV-rtPA when final diagnosis was not ischemic stroke. METHODS We reviewed the records of 535 IV-rtPA-treated patients who presented to our primary stroke centers. The diagnosis of SM or transient ischemic attack (TIA) was based on patient presentation, hospital course, electroencephalography, and negative neuroimaging studies. The excess cost analysis compared actual direct and indirect hospital costs of a patient to what their direct and indirect hospital costs would have been had they primarily been diagnosed with mimic or TIA. RESULTS Seventy-four patients post-IV-rtPA treatment had final diagnosis of SM; 21 had TIAs. The excess direct and indirect hospital costs for mimics were

Atrial tachycardia provoked in the presence of activating autoantibodies to β2-adrenergic receptor in the rabbit

257,975 and

FABS: An Intuitive Tool for Screening of Stroke Mimics in the Emergency Department

152,813, respectively. The median excess cost was

Systemic thrombolysis in acute ischemic stroke patients with unruptured intracranial aneurysms

5401 per admission. The excess total cost for TIAs was

The Propensity for Inducing Atrial Fibrillation: A Comparative Study on Old versus Young Rabbits.

85,026 with a median of

Internet-based information-seeking behavior for transient ischemic attack

3407 per admission. CONCLUSIONS Administration of IV-rtPA to patients with SMs remains prevalent and costly. Certain clinical or radiographic characteristics can help diagnose mimics; however, more studies need to be done to determine the feasibility and effectiveness of further clinical investigations among suspected SM patients who are within the thrombolysis treatment window.

Fluid-Attenuated Inversion Recovery (FLAIR) Signal Intensity Can Identify Stroke Within 6 and 8 Hours

BACKGROUND A recent clinical study of patients with inappropriate sinus tachycardia reported that autoantibodies to β-adrenergic receptors (β2ARs) could act as agonists to induce atrial arrhythmias. OBJECTIVE To test the hypothesis that activating autoantibodies to the β2AR in the rabbit atrium are arrhythmogenic. METHODS Five New Zealand white rabbits were immunized with a β2AR second extracellular loop peptide to raise β2AR antibody titers. A catheter-based electrophysiologic study was performed on anesthetized rabbits before and after immunization. Arrhythmia occurrence was determined in response to burst pacing before and after the infusion of acetylcholine in incremental concentrations of 10 μM, 100 μM, and 1 mM at 1 mL/min. RESULTS In the preimmune studies when β2AR antibody titers were undetectable, of a total of 20 events, only 3 episodes of nonsustained (<10 seconds) atrial arrhythmias were induced. In the postimmune studies when β2AR antibody titers ranged from 1:160,000 to 1:1.28 million, burst pacing induced 10 episodes of nonsustained or sustained (≥10 seconds) arrhythmias in 20 events (P = .04 vs preimmune; χ(2) and Fisher exact test). Taking into account only the sustained arrhythmias, there were 6 episodes in 20 events in the postimmune studies compared with 0 episodes in 20 events in the preimmune studies (P = .02). Immunized rabbits demonstrated immunoglobulin G deposition in the atria, and their sera induced significant activation of β2AR in transfected cells in vitro compared to the preimmune sera. CONCLUSIONS Enhanced autoantibody activation of β2AR in the rabbit atrium leads to atrial arrhythmias mainly in the form of sustained atrial tachycardia.

Critical Care of Brain Reperfusion

Background and Purpose— A large number of patients with symptoms of acute cerebral ischemia are stroke mimics (SMs). In this study, we sought to develop a scoring system (FABS) for screening and stratifying SM from acute cerebral ischemia and to identify patients who may require magnetic resonance imaging to confirm or refute a diagnosis of stroke in the emergency setting. Methods— We designed a scoring system: FABS (6 variables with 1 point for each variable present): absence of Facial droop, negative history of Atrial fibrillation, Age <50 years, systolic Blood pressure <150 mm Hg at presentation, history of Seizures, and isolated Sensory symptoms without weakness at presentation. We evaluated consecutive patients with symptoms of acute cerebral ischemia and a negative head computed tomography for any acute finding within 4.5 hours after symptom onset in 2 tertiary care stroke centers for validation of FABS. Results— A total of 784 patients (41% SMs) were evaluated. Receiver operating characteristic curve (C statistic, 0.95; 95% confidence interval [CI], 0.93–0.98) indicated that FABS≥3 could identify patients with SM with 90% sensitivity (95% CI, 86%–93%) and 91% specificity (95% CI, 88%–93%). The negative predictive value and positive predictive value were 93% (95% CI, 90%–95%) and 87% (95% CI, 83%–91%), respectively. Conclusions— FABS seems to be reliable in stratifying SM from acute cerebral ischemia cases among patients in whom the head computed tomography was negative for any acute findings. It can help clinicians consider advanced imaging for further diagnosis.

Spontaneous dissection of the bilateral internal carotid and vertebral arteries: A rationale for endovascular management

Objective: We sought to determine the safety of IV thrombolysis (IVT) in acute ischemic stroke (AIS) patients harboring unruptured intracranial aneurysm (UIA) in a multicenter study and a comprehensive meta-analysis of available case series. Methods: We analyzed prospectively collected data from consecutive AIS patients treated with IVT during a 4-year period at 4 tertiary-care stroke centers. All patients routinely underwent CT or magnetic resonance angiography during hospitalization. The presence of UIA was documented on the basis of neuroradiology reports. Symptomatic intracranial hemorrhage (sICH) was defined as imaging evidence of ICH combined with an increase in NIH Stroke Scale score of ≥4 points. A systematic meta-analysis of case series reporting safety of IVT in AIS with concomitant UIA was conducted according to PRISMA recommendations. Results: Among 1,398 AIS patients treated with IVT, we identified 42 cases (3.0%) harboring a total of 48 UIAs. The rates of symptomatic and asymptomatic ICH were 2.4% (95% confidence interval [CI] by adjusted Wald method: 0%–12.6%) and 7.1% (95% CI: 1.8%–19.7%), respectively. A total of 5 case series met our inclusion criteria for meta-analysis, and the pooled rate of sICH among 120 IVT-treated AIS patients harboring UIA was 6.7% (95% CI: 3.1%–13.7%). In the overall analysis of 5 case-series studies, the risk ratio of sICH did not differ between AIS patients with and without UIA (risk ratio = 1.60; 95% CI: 0.54–4.77; p = 0.40) with no evidence of heterogeneity across included studies (I2 = 22% and p = 0.27 for Cochran Q test). Conclusions: Our prospectively collected multicenter data, coupled with the findings of the meta-analysis, indicate the potential safety of IVT in AIS patients with UIA.