Ian S. deSouza

Adenosine for wide-complex tachycardia: Efficacy and safety*

Objectives:To determine whether adenosine is useful and safe as a diagnostic and therapeutic agent for patients with undifferentiated wide QRS complex tachycardia. The etiology of sustained monomorphic wide QRS complex tachycardia is often uncertain acutely. Design:A retrospective observational study. Setting:Treatment associated with emergency visits at nine urban hospitals. Patients:Consecutive patients treated with adenosine for regular wide QRS complex tachycardia between 1991 and 2006. Interventions:Treatment with adenosine infusion. Measurements and Main Results:Measured outcomes included rhythm response to adenosine, if any, and all adverse effects. A positive response was defined as an observed change in rhythm including temporary atrioventricular conduction block or tachycardia termination. A primary adverse event was defined as emergent electrical or medical therapy instituted in response to an adverse adenosine effect. A rhythm diagnosis was made in each case. The characteristics of adenosine administration as a test for a supraventricular as opposed to ventricular tachycardia were determined, and the adverse event rates were calculated. A total of 197 patients were included: 104 (90%) of 116 (95% confidence interval, 83%–95%) and two (2%) of 81 (95% confidence interval, 0.3%–9%) supraventricular tachycardia and ventricular tachycardia patients demonstrated a response to adenosine, respectively. The odds of supraventricular tachycardia increased by a factor of 36 (95% confidence interval, 9–143) after a positive response to adenosine. The odds of ventricular tachycardia increased by a factor of 9 (95% confidence interval, 6–16) when there was no response to adenosine. The rate of primary adverse events for patients with supraventricular tachycardia and ventricular tachycardia was 0 (0%) of 116 (95% confidence interval, 0%–3%) and 0 (0%) of 81 (95% confidence interval, 0%–4%), respectively. Conclusions:Adenosine is useful and safe as a diagnostic and therapeutic agent for patients with regular wide QRS complex tachycardia.

Amiodarone or Procainamide for the Termination of Sustained Stable Ventricular Tachycardia: An Historical Multicenter Comparison

OBJECTIVES The objective was to compare the effectiveness of intravenous (IV) procainamide and amiodarone for the termination of spontaneous stable sustained ventricular tachycardia (VT). METHODS A historical cohort study of consecutive adult patients with stable sustained VT treated with IV amiodarone or procainamide was performed at four urban hospitals. Patients were identified for enrollment by admissions for VT and treatment with the study agents in the emergency department (ED) from 1993 to 2008. The primary measured outcome was VT termination within 20 minutes of onset of study medicine infusion. A secondary effectiveness outcome was the ultimate need for electrical therapy to terminate the VT episode. Major adverse effects were tabulated, and blood pressure responses to medication infusions were compared. RESULTS There were 97 infusions of amiodarone or procainamide in 90 patients with VT, but the primary outcome was unknown after 14 infusions due to administration of another antidysrhythmic during the 20-minute observation period. The rates of VT termination were 25% (13/53) and 30% (9/30) for amiodarone and procainamide, respectively. The adjusted odds of termination with procainamide compared to amiodarone was 1.2 (95% confidence interval [CI]=0.4 to 3.9). Ultimately, 35/66 amiodarone patients (53%, 95% CI=40 to 65%) and 13/31 procainamide patients (42%, 95% CI=25 to 61%) required electrical therapy for VT termination. Hypotension led to cessation of medicine infusion or immediate direct current cardioversion (DCCV) in 4/66 (6%, 95% CI=2 to 15%) and 6/31 (19%, 95% CI=7 to 37%) patients who received amiodarone and procainamide, respectively. CONCLUSIONS Procainamide was not more effective than amiodarone for the termination of sustained VT, but the ability to detect a significant difference was limited by the study design and potential confounding. As used in practice, both agents were relatively ineffective and associated with clinically important proportions of patients with decreased blood pressure.

Antidysrhythmic drug therapy for the termination of stable, monomorphic ventricular tachycardia: a systematic review

Objective We performed a systematic review of the literature to compare the efficacy of different drug therapies for the termination of stable, monomorphic ventricular tachycardia (VT). Methods We searched EMBASE, MEDLINE and Cochrane for trials from 1965 through July 2013 using a search strategy derived from the following clinical question in PICO format: Patients: Adults (≥18 years) with stable monomorphic VT; Intervention: Intravenous antidysrhythmic drug; Comparator: Intravenous lidocaine or amiodarone; Outcome: Termination of VT. For all drug comparisons, we calculated relative risks (RR; 95% CI) and number needed to treat (NNT, 95% CI) between drugs. We also evaluated the methodological quality of the studies. Results Our search yielded 219 articles by PubMed and 390 articles by EMBASE. 3 prospective studies (n=93 patients) and 2 retrospective studies (n=173 patients) met our inclusion and exclusion criteria. From the prospective studies, RR of VT termination of procainamide versus lidocaine was 3.7 (1.3–10.5); ajmaline versus lidocaine, RR=5.3 (1.4–20.5); and sotalol versus lidocaine, RR=3.9 (1.3–11.5). From the retrospective studies: procainamide versus lidocaine, RR=2.2 (1.2–4.0); and procainamide versus amiodarone RR=4.3 (0.8–23.6). All 5 reviewed studies had quality issues, including potential bias for randomisation and concealment. Conclusions Based on limited available evidence from small heterogeneous human studies, for the treatment of stable, monomorphic VT, procainamide, ajmaline and sotalol were all superior to lidocaine; amiodarone was not more effective than procainamide.

β-Blockers versus calcium channel blockers for acute rate control of atrial fibrillation with rapid ventricular response: a systematic review.

This is a systematic review of the literature to compare the efficacy of calcium channel blockers to &bgr;-blockers for acute rate control of atrial fibrillation with rapid ventricular response in the emergency department setting. PubMed, EMBASE, and the Cochrane Registry were searched. Relative risk (95% confidence interval) was calculated between drugs and methodological quality of included studies was evaluated. Of the 1003 studies yielded by our initial search, two met inclusion criteria and provided sufficient data. These were randomized double-blinded studies (n=92) comparing intravenous diltiazem with intravenous metoprolol. The combined relative risk of acute rate control by diltiazem versus metoprolol was 1.8 (95% confidence interval 1.2–2.6). On the basis of the paucity of available evidence, diltiazem may be more effective than metoprolol in achieving rapid rate control, but high-quality randomized studies are needed.

Serial Sonographic Assessment of Pulmonary Edema in Patients With Hypertensive Acute Heart Failure

Objective measures of clinical improvement in patients with acute heart failure (AHF) are lacking. The aim of this study was to determine whether repeated lung sonography could semiquantitatively capture changes in pulmonary edema (B‐lines) in patients with hypertensive AHF early in the course of treatment.