Current and investigational therapies for the treatment of refractory ventricular fibrillation

Disclaimer In an effort to expedite the publication of articles related to the COVID-19 pandemic, AJHP is posting these manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. Purpose Esmolol, dual sequential defibrillation, vector change defibrillation, and left stellate ganglion block are presented and reviewed for the treatment of refractory ventricular fibrillation. Summary Although no formal definition has been established for refractory ventricular fibrillation, the literature describes it as a pulseless ventricular arrhythmia that persists despite 3 standard defibrillation attempts, administration of amiodarone 300 mg intravenously, and provision of three 1-mg intravenous doses of epinephrine. Evolving literature surrounding resuscitation in this particular subset of cardiac arrest challenges the efficacy of traditional therapies, such as epinephrine, and suggests that other treatment modalities may improve outcomes. Case reports, case series, and small retrospective studies have pointed to benefit when utilizing a variety of therapies, namely, esmolol, dual sequential defibrillation, vector change defibrillation, or left stellate ganglion block, in patients with refractory ventricular fibrillation arrest. Conclusion A mounting, although limited, body of evidence suggests that esmolol, dual sequential defibrillation, vector change defibrillation, or left stellate ganglion block may be effective at terminating refractory ventricular fibrillation and improving patient outcomes. Further evidence is required before these therapies can be adopted as standard practice; however, as key members of the code response team, it is imperative for pharmacists to be familiar with the supporting evidence, safety considerations, and logistical challenges of utilizing these treatments during arrest.

Electrocardiographic Predictors of Primary Ventricular Fibrillation and 30-Day Mortality in Patients Presenting with ST-Segment Elevation Myocardial Infarction

Primary ventricular fibrillation (PVF) may occur in the early phase of ST-elevation myocardial infarction (STEMI) prior to primary percutaneous coronary intervention (PCI). Multiple electrocardiographic STEMI patterns are associated with PVF and short-term mortality including the tombstone, Lambda, and triangular QRS-ST-T waveform (TW). We aimed to compare the predictive value of different electrocardiographic STEMI patterns for PVF and 30-day mortality. We included a consecutive cohort of 407 STEMI patients (75% males, median age 66 years) presenting within 12 h of symptoms onset. At first medical contact, 14 (3%) showed the TW or Lambda ECG patterns, which were combined in a single group (TW-Lambda pattern) characterized by giant R-wave and downsloping ST-segment. PVF prior to primary PCI occurred in 39 (10%) patients, significantly more often in patients with the TW-Lambda pattern than those without (50% vs. 8%, p < 0.001). For the multivariable analysis, Killip class ≥3 (OR 6.19, 95% CI 2.37–16.1, p < 0.001) and TW-Lambda pattern (OR 9.64, 95% CI 2.99–31.0, p < 0.001) remained as independent predictors of PVF. Thirty-day mortality was also higher in patients with the TW-Lambda pattern than in those without (43% vs. 6%, p < 0.001). However, only LVEF (OR 0.86, 95% CI 0.82–0.90, p < 0.001) and PVF (OR 4.61, 95% CI 1.49–14.3, p = 0.042) remained independent predictors of mortality. A mediation analysis showed that the effect of TW-Lambda pattern on mortality was mediated mainly via the reduced LVEF. In conclusion, among patients presenting with STEMI, the electrocardiographic TW-Lambda pattern was associated with both PVF before PCI and 30-day mortality. Therefore, this ECG pattern may be useful for early risk stratification of STEMI.

700 The role of Impella CP in the management of malignant arrhythmias: a case of asymptomatic ventricular fibrillation

Introduction The Impella Heart Pump device (Abiomed, Danvers, MA, USA) is commonly used to provide mechanical circulatory support during high-risk percutaneous coronary intervention (PCI) and has demonstrated both efficacy and safety in patients with cardiogenic shock. Left ventricular assist devices (LVADs) alter the pathophysiological impact of ventricular arrhythmias in advanced heart failure; for example, life-threatening arrhythmias such as ventricular fibrillation (VF). We present a case of sustained VF tolerance in a patient with IMPELLA CP® support. Methods and results A 64-year-old man was admitted with typical chest pain that began 3 days earlier and an anterior myocardial infarction with ST-segment elevation. Urgent coronary angiogram showed a left anterior descending artery treated with angioplasty and stent implantation (TIMI 3). An initial echocardiogram, performed after PCI, showed a reduced left ventricular ejection fraction (LVEF) of approximately 35% with good right ventricular function. Two days later, the ECG tracing showed persistence of the ST elevation, and the patient developed recurrent ventricular tachycardia and an episode of acute pulmonary oedema; the echocardiogram showed a significant worsening of LVEF (15%). A percutaneous mechanical circulatory support device (Impella CP; Abiomed) was inserted through the right common femoral artery in order to preserve adequate systemic perfusion (Figure 1A). Twelve hours later, the patient developed rapid VT degenerating into VF without loss of consciousness (Figure 1C). During the arrhythmia, the patient was alert and his mental status was normal, Impella flow was 2.4–3.0 l/min, and invasive blood pressure (IBP) was 80/65 mmHg (Figure 1D). Intravenous lidocaine was administered without effect. After approximately 10 min of incessant VF, the patient received sedation with propofol from the anesthesiologist. A single unsynchronized DC shock of 200 J converted the patient to sinus rhythm. A bedside transthoracic echocardiogram was performed to check the optimal position of the Impella device (Figure 1B). In the following days, the patient had two new episodes of asymptomatic VF treated with DC-shock after sedation and was transferred to the cardiac surgery department to undergo urgent LVAD implantation. Conclusions Impella CP was helpful in the management of this patient with severe heart failure and malignant ventricular tachyarrhythmias, reducing the hemodynamic and neurological impact of this latter catastrophic arrhythmic event.

Torsades de pointes in the PACU after outpatient endoscopy: a case report

Background This case demonstrates the severe electrolyte derangements that may present after a common therapy such as a bowel preparation for an outpatient procedure and the rare yet potential detrimental outcomes of those abnormalities. It also highlights the implications of long QT syndrome regarding pharmacology and treatment. Case presentation We present a case of 48 year-old female with severe electrolyte derangements and long QT syndrome (LQTS) leading to Torsades de Pointes (TdP), pulseless ventricular fibrillation, and unsynchronized defibrillation in the post anesthesia care unit (PACU) after uneventful upper and lower endoscopy. This led to an unanticipated intensive care unit admission for aggressive electrolyte repletion, cardiology consultation, and implantable cardioverter defibrillator (ICD) placement. Conclusions This is a rare presentation after an outpatient procedure that would have had a detrimental outcome if not promptly diagnosed and treated appropriately. Therefore, we aim to provide further insight into the diagnosis and treatment of severe hypokalemia and long QT syndrome resulting in Torsades de Pointes and ventricular fibrillation.