Thyroid storm is a rare yet critical complication of uncontrolled thyrotoxicosis, posing significant challenges in clinical management. We present the case of a 65-year-old African-American female with a medical history significant for untreated Graves\' disease, hypertension, and diverticulosis, who presented with escalating abdominal pain, accompanied by nausea, vomiting, diarrhea, and chest discomfort. Upon admission, she exhibited atrial fibrillation with rapid ventricular response (RVR) and newly diagnosed high-output cardiac failure. Diagnosis of thyroid storm was confirmed through comprehensive laboratory assessments and clinical evaluation. Treatment with beta-blockers, anti-thyroid medications, and corticosteroids facilitated stabilization of her condition. This case report highlights the importance of early identification and intervention in thyroid storm to avert potential morbidity and mortality.

Atrial fibrillation (AF) may lead to stroke, heart failure, and death. When AF occurs in the context of a rapid ventricular rate/response (RVR), this can lead to complications, including hypoperfusion and cardiac ischemia. Emergency physicians play a key role in the diagnosis and management of this dysrhythmia.
This paper evaluates key evidence-based updates concerning AF with RVR for the emergency clinician.
Differentiating primary and secondary AF with RVR and evaluating hemodynamic stability are vital components of ED assessment and management. Troponin can assist in determining the risk of adverse outcomes, but universal troponin testing is not required in patients at low risk of acute coronary syndrome or coronary artery disease - especially patients with recurrent episodes of paroxysmal AF that are similar to their prior events. Emergent cardioversion is indicated in hemodynamically unstable patients. Rate or rhythm control should be pursued in hemodynamically stable patients. Elective cardioversion is a safe option for select patients and may reduce AF symptoms and risk of AF recurrence. Rate control using beta blockers or calcium channel blockers should be pursued in those with AF with RVR who do not undergo cardioversion. Anticoagulation is an important component of management, and several tools (e.g., CHA2DS2-VASc) are available to assist with this decision. Direct oral anticoagulants are the first-line medication class for anticoagulation. Disposition can be challenging, and several risk assessment tools (e.g., RED-AF, AFFORD, and the AFTER (complex, modified, and pragmatic) scores) are available to assist with disposition decisions.
An understanding of the recent updates in the literature concerning AF with RVR can assist emergency clinicians in the care of these patients.

Patients with atrial fibrillation-related stroke (AF-stroke) are prone to developing rapid ventricular response (RVR). We investigated whether RVR is associated with initial stroke severity, early neurological deterioration (END) and poor outcome at 3 months.
We reviewed patients who had AF-stroke between January 2017 and March 2022. RVR was defined as having heart rate >100 beats per minute on initial electrocardiogram. Neurological deficit was evaluated with National Institutes of Health Stroke Scale (NIHSS) score at admission. END was defined as increase of ≥2 in total NIHSS score or ≥1 in motor NIHSS score within first 72 h. Functional outcome was score on modified Rankin Scale at 3 months. Mediation analysis was performed to examine potential causal chain in which initial stroke severity may mediate relationship between RVR and functional outcome.
We studied 568 AF-stroke patients, among whom 86 (15.1%) had RVR. Patients with RVR had higher initial NIHSS score (p < 0.001) and poor outcome at 3 months (p = 0.004) than those without RVR. The presence of RVR [adjusted odds ratio (aOR) = 2.13; p = 0.013] was associated with initial stroke severity, but not with END and functional outcome. Otherwise, initial stroke severity [aOR = 1.27; p = <0.001] was significantly associated with functional outcome. Initial stroke severity as a mediator explained 58% of relationship between RVR and poor outcome at 3 months.
In patients with AF-stroke, RVR was independently associated with initial stroke severity but not with END and functional outcome. Initial stroke severity mediated considerable proportion of association between RVR and functional outcome.

Diltiazem is an antiarrhythmic drug widely used in the treatment of atrial fibrillation (AFib) with rapid ventricular response (RVR). It reveals its effect by blocking L-type calcium channels. Thus, it inhibits the extracellular calcium influx into the cytosol. The relationship between serum calcium level and the efficacy of intravenous (IV) diltiazem used in the treatment of AFib with RVR has not been investigated in vivo. The aim of this study is to investigate the mentioned relationship.
This study was planned as a single-center retrospective study. The data of 349 patients who presented to the emergency department with AFib with RVR and treated with diltiazem were retrospectively analyzed. A patient was considered to have responded to diltiazem treatment if the existing heart rhythm returned to sinus rhythm, or the heart rate decreased below 100 beats/min, or the heart rate decreased >20% provided that it was below 120 beats/min. The ionized calcium levels were recorded. The relationship between serum calcium level and the success of diltiazem treatment was examined.
Fifty five percent of the patients were female. The median age was 75 years. The rate of response to diltiazem treatment was 67.3%. The median of ionized calcium levels in the group which responded to diltiazem treatment (n = 235) was 1.14 mmol/L (IQR: 0.12), and the group which did not respond to diltiazem treatment (n = 114) was 1.11 mmol/L (IQR: 0.12) (p = 0.322). The patients were divided into three groups as low, normal, and high calcium levels according to the calcium reference levels determined by the hospital laboratory. The rate of response to diltiazem treatment was 61.4% in patients with low ionized calcium levels, 76.1% in patients with normal ionized calcium levels, and 40.0% in patients with high ionized calcium levels. The rate of response to diltiazem treatment was higher in patients with normal ionized calcium levels compared to patients with low or high ionized calcium levels (p = 0.004, p = 0.003).
The success rate of diltiazem used in the treatment of AFib with RVR was highest in physiological calcium levels. The current study may provide the clinician with awareness about the consideration of serum ionized calcium levels when choosing drugs in patients with AFib with RVR.

The objective was to evaluate the comparative effectiveness and safety of pharmacological and nonpharmacological management options for atrial fibrillation/atrial flutter with rapid ventricular response (AFRVR) in patients with acute decompensated heart failure (ADHF) in the acute care setting.
This study was a systematic review of observational studies or randomized clinical trials (RCT) of adult patients with AFRVR and concomitant ADHF in the emergency department (ED), intensive care unit, or step-down unit. The primary effectiveness outcome was successful rate or rhythm control. Safety outcomes were adverse events, such as symptomatic hypotension and venous thromboembolism.
A total of 6577 unique articles were identified. Five studies met inclusion criteria: one RCT in the inpatient setting and four retrospective studies, two in the ED and the other three in the inpatient setting. In the RCT of diltiazem versus placebo, 22 patients (100%) in the treatment group had a therapeutic response compared to 0/15 (0%) in the placebo group, with no significant safety differences between the two groups. For three of the observational studies, data were limited. One observation study showed no difference between metoprolol and diltiazem for successful rate control, but worsening heart failure symptoms occurred more frequently in those receiving diltiazem compared to metoprolol (19 patients [33%] vs. 10 patients [15%], p = 0.019). A single study included electrical cardioversion (one patient exposed with failure to convert to sinus rhythm) as nonpharmacological management. The overall risk of bias for included studies ranged from serious to critical. Missing data and heterogeneity of definitions for effectiveness and safety outcomes precluded the combination of results for quantitative meta-analysis.
High-level evidence to inform clinical decision making regarding effective and safe management of AFRVR in patients with ADHF in the acute care setting is lacking.

OBJECTIVE: The 2021 European Society of Cardiology guidelines on acute and chronic heart failure (HF) recommend that non-dihydropyridine calcium channel blockers (NDCC) should be avoided in patients with HF with reduced ejection fraction. It also emphasizes that beta-blockers only be initiated in clinically stable, euvolemic patients. Despite these recommendations, NDCC and beta-blockers are often still employed in patients with AF with rapid ventricular response and acute decompensated HF. The relative safety and efficacy of these therapies in this setting is unclear.
METHODS: To address the question of the safety and efficacy of NDCC and beta-blockers for acute rate control in decompensated HF, we provide a perspective on the literature of NDCC and beta-blockers in chronic HF with reduced and preserved ejection fraction and AF, including trials on the management of AF with rapid ventricular response with and without HF.
RESULTS: Robust data demonstrates mortality benefits when beta-blockers are used in patients with chronic HF with reduced ejection fraction. The data that inform the contraindication of NDCC in HF with reduced ejection fraction are outdated and were not primarily designed to address the efficacy and safety of rate control of AF in patients with HF. Several studies indicate that for acute rate control, NDCC and beta-blockers are both efficacious therapies, especially in the setting of tachycardia-induced cardiomyopathy.
CONCLUSIONS: Future studies are needed to assess the safety and efficacy of beta-blockers and NDCC in both acute and chronic AF with HF with reduced and preserved ejection fraction.

Introduction Diltiazem is commonly used for the management of atrial fibrillation (AFIB) with rapid ventricular rate (RVR) in the emergency department (ED). Conflicting studies comparing the efficacy of diltiazem have led to various dosing strategies. The objective of this study was to investigate diltiazem administration in a community ED and determine the effect of varying doses on heart rate (HR) control, systolic blood pressure (SBP) and diastolic blood pressure (DBP). Methods This is a retrospective, single-center study of adult patients treated with diltiazem for AFIB-RVR in the ED between January 1 and December 31, 2019. Inclusion criteria included pretreatment HR > 120 beats per minute (bpm). Patients were administered diltiazem at the discretion of the ED physician. Primary endpoint was time to achieve HR < 100 bpm after diltiazem. Secondary endpoints included mean weight-based dose of diltiazem, percentage of patients achieving HR < 100 bpm within 240 minutes of diltiazem, nadir SBP and nadir DBP. Results Ninety-nine patients were included in the study. Seventy-two percent of patients received ≤ 10 mg diltiazem bolus. Mean weight-based dose of diltiazem bolus was 0.13 mg/kg. Mean time to achieve HR < 100 bpm was 270 minutes for the entire cohort. Patients treated with ≥ 0.13 mg/kg diltiazem achieved an HR < 100 bpm at a mean time of 169 minutes compared to 318 minutes for < 0.13 mg/kg (p = 0.0107). HR control was achieved in 61% of patients who received ≥ 0.13 mg/kg compared to 36% of patients who received < 0.13 mg/kg diltiazem (p = 0.0213). No patients discontinued diltiazem for hypotension or bradycardia. The lowest recorded SBP and DBP within 240 minutes of diltiazem were 90 mmHg and 47 mmHg, respectively. There was no significant difference in the lowest SBP and DBP for patients who received < 0.13 mg/kg compared to ≥ 0.13 mg/mg diltiazem. Conclusion The majority of patients with AFIB RVR received a 10 mg non-weight-based diltiazem bolus dose in the ED. Diltiazem bolus dosing ≥ 0.13 mg/kg was associated with significantly improved times to achieve HR control compared to < 0.13 mg/kg and was not associated with hypotension or bradycardia.

Management of atrial fibrillation includes either rhythm control that aims at establishing a sinus rhythm or rate control that aims at lowering the ventricular rate, usually with atrioventricular nodal blocking agents. Another potential strategy for ventricular rate control is to induce a negative dromotropic effect by augmenting cardiac vagal activity, which might be possible through noninvasive and nonpharmacologic techniques. Thus, the hypothesis of this study was that occipitoatlantal decompression (OA-D) and transcutaneous auricular vagus nerve stimulation (taVNS) not only increase cardiac parasympathetic tone as assessed by heart rate variability (HRV), but also slow atrioventricular conduction, assessed by the PQ-interval of the electrocardiogram (EKG) in generally healthy study participants without atrial fibrillation.
To test whether OA-D and/or transcutaneous taVNS, which have been demonstrated to increase cardiac parasympathetic nervous system activity, would also elicit a negative dromotropic effect and prolong atrioventricular conduction.
EKGs were recorded in 28 healthy volunteers on three consecutive days during a 30 min baseline recording, a 15 min intervention, and a 30 min recovery period. Participants were randomly assigned to one of three experimental groups that differed in the 15 min intervention. The first group received OA-D for 5 min, followed by 10 min of rest. The second group received 15 min of taVNS. The intervention in the third group that served as a time control group (CTR) consisted of 15 min of rest. The RR- and PQ-intervals were extracted from the EKGs and then used to assess HRV and AV-conduction, respectively.
The OA-D group had nine participants (32.1%), the taVNS group had 10 participants (35.7%), and the CTR group had nine participants (32.1%). The root mean square of successive differences between normal heartbeats (RMSSD), an HRV measure of cardiac parasympathetic modulation, tended to be higher during the recovery period than during the baseline recording in the OA-D group (mean ± standard error of the mean [SEM], 54.6 ± 15.5 vs. 49.8 ± 15.8 ms; p<0.10) and increased significantly in the taVNS group (mean ± SEM, 28.8 ± 5.7 vs. 24.7 ± 4.8 ms; p<0.05), but not in the control group (mean ± SEM, 31.4 ± 4.2 vs. 28.5 ± 3.8 ms; p=0.31). This increase in RMSSD was accompanied by a lengthening of the PQ-interval in the OA-D (mean ± SEM, 170.5 ± 9.6 vs. 166.8 ± 9.7 ms; p<0.05) and taVNS (mean ± SEM, 166.6 ± 6.0 vs. 162.1 ± 5.6 ms; p<0.05) groups, but not in the control group (mean ± SEM, 164.3 ± 9.2 vs. 163.1 ± 9.1 ms; p=0.31). The PQ-intervals during the baseline recordings did not differ on the three study days in any of the three groups, suggesting that the negative dromotropic effect of OA-D and taVNS did not last into the following day.
The lengthening of the PQ-interval in the OA-D and taVNS groups was accompanied by an increase in RMSSD. This implies that the negative dromotropic effects of OA-D and taVNS are mediated through an increase in cardiac parasympathetic tone. Whether these findings suggest their utility in controlling ventricular rates during persistent atrial fibrillation remains to be determined.

BACKGROUND: Atrial fibrillation and atrial flutter are common supraventricular arrhythmias in patients who present to the emergency department. Under the American Heart Association guidelines, dilTIAZem is the calcium channel blocker frequently used by many practitioners for rate control. Currently, institution-specific data have identified that many patients receiving dilTIAZem for atrial fibrillation or atrial flutter are given initial doses that exceed the recommended dose by more than 10%, resulting in hypotension in some patients.
METHODS: ED personnel were surveyed to determine their current knowledge of appropriate intravenous dilTIAZem dosing and methods of prescribing intravenous dilTIAZem to determine the causes of higher dosing. Based on the baseline data, an intervention of adding a text alert when withdrawing dilTIAZem from the automated medication dispensing cabinet was implemented.
RESULTS: Following the intervention, 29 patients received intravenous dilTIAZem for rate control of atrial fibrillation or flutter with rapid ventricular response. For the primary outcome, the incidence of high-dose dilTIAZem decreased by 19% (P = 0.03). There was no change in the secondary outcome of a reduction in hypotension (P = 0.3).
CONCLUSIONS: The interventions of education and medication alerts resulted in a significant increase in the percentage of patients receiving appropriate doses of dilTIAZem and a nonsignificant decrease in the incidence of hypotension. This process-oriented intervention resulted in an improvement in appropriate dilTIAZem doses at our site. Rate control was not statistically significantly different between the 2 groups. Long-term sustainability of this intervention requires further study.

BACKGROUND: Despite evidence-based recommended weight-based (WB) dosing of diltiazem for the initial treatment of atrial fibrillation (AF) with rapid ventricular response (RVR), many providers utilize lower initial doses of diltiazem.
OBJECTIVE: We sought to determine whether a low, standard dose of diltiazem is noninferior to WB diltiazem as an initial bolus dose in the treatment of AF with RVR.
METHODS: This retrospective review included patients who presented to the emergency department (ED) of an urban, academic tertiary medical center experiencing AF with RVR from November 2010 to August 2014. Adult patients were categorized by the dose of diltiazem received; 10 mg standard dose or 0.2-0.3 mg/kg WB dose. The primary outcome of successful treatment was defined as a composite of the following parameters 15 min after the initial bolus dose: heart rate (HR) < 100 beats/min, reduction of HR ≥ 20%, or a conversion to normal sinus rhythm.
RESULTS: Four hundred and fifty-six patients who received diltiazem were included for study evaluation (standard dose: n = 255 patients, WB: n = 201 patients). Baseline characteristics, medical history, and medication use before ED presentation were similar between the groups. Significant differences at baseline between the groups included weight and HR at presentation. The primary outcome of successful treatment was attained in 60.8% of the standard dose patients and 68.7% of the WB patients (p = 0.082).
CONCLUSIONS: In patients presenting to the ED, we found that standard dose diltiazem was noninferior to WB dosing in the initial treatment of AF with RVR.