2 Minute Medicine Rewind May 9, 2016

Ventricular Tachycardia Ablation versus Escalation of Antiarrhythmic Drugs

The purpose of this multicenter, randomized, controlled trial was to determine the most effective approach to management of recurrent ventricular tachycardia in patients post-MI with an implantable cardioverter-defibrillator (ICD) despite antiarrhythmic drug therapy. A total of 132 patients were randomly assigned to receive catheter ablation (with continuation of baseline antiarrhythmic medications), and 127 patients were assigned to the escalated antiarrhythmic drug therapy group with amiodarone (or increased amiodarone dose if the patient was previously on this agent. If already on high dose amiodarone then mexiletine was added). The primary outcome was composite of death, three or more documented episodes of ventricular tachycardia within 24 hours, or appropriate ICD shock. The authors found that the primary outcome occurred more commonly in the escalated-therapy group (68.5% of those in the escalated-therapy group vs 59.1% of patients in the ablation group; HR 0.72; 95% CI 0.53 to 0.98; p = 0.04). There were no differences in mortality between groups. The results of this trial provide evidence that catheter ablation resulted in a significantly lower rate of the composite primary outcome of death, ventricular tachycardia storm, or appropriate ICD shock compared to patients receiving an escalation in antiarrhythmic drug therapy.

Randomized Trial of Introduction of Allergenic Foods in Breast-Fed Infants

The purpose of this randomized controlled trial in the United Kingdom was to determine whether the early introduction of common dietary allergens (such as peanut, cooked hen’s egg, cow’s milk, sesame, whitefish, and wheat) from 3 months of age in exclusively breast-fed infants would prevent food allergies. A total of 1303 patients at 3 months of age were randomly assigned to either receive six allergenic foods (peanut, cooked egg, cow’s milk, sesame, whitefish, and wheat; early-introduction group) or to the current practice recommended of exclusive breast-feeding to approximately 6 months of age (standard-introduction group). The primary outcome of this study was food allergy to one or more of the six foods between 1 year and 3 years of age. The authors found in the intention-to-treat analysis no significant difference in development of a food allergy to one or more of the six intervention foods in the standard-introduction group compared to the early-introduction group (7.1% of patients vs 5.6%, respectively; p=0.32). However, in the per-protocol analysis significantly lower relative risks of peanut allergy and egg allergy were observed in the early-introduction group compared to the standard-introduction group (p = 0.003 and p = 0.009, respectively). Increased amount of consumption of food allergens was associated with a significantly lower prevalence of these allergies. Therefore, the results of this study (i.e. intention to treat analysis) did not provide evidence that early introduction of allergenic food resulted in less food allergies, however perhaps the prevention of food allergy by means of early introduction of multiple allergenic foods is dose-dependent, as evident by the subgroup analysis.

Degree and Timing of Intensive Blood Pressure Lowering on Hematoma Growth in Intracerebral Hemorrhage

After a spontaneous intracerebral hemorrhage (ICH), increased systolic blood pressure (BP) is common. The degree and timing of BP lowering is relation to hematoma growth was assessed by authors in INTERACT2, an international, multicenter, open, blinded randomized controlled trial with 2839 patients. They compared intensive BP lowering (target systolic BP <140mmHg within 1 hour) compared to guideline-recommended (systolic BP <180mmHg). In a substudy, 24 hour CT brain scan was performed on 964 patients. The authors found greater systolic BP reduction was associated with reduced hematoma growth. More specifically, a change in systolic BP of <10, 10- to 20, and ≥20 mmHg reduction was associated with hematoma growth of 13.3mL, 5.0mL, and 3.0mL, respectively (P <0.001), irrespective of whether they received intensive or guideline-based BP lowering treatment. Intensive systolic BP was achieved in 242 (49%) of patients in less than 1 hour and in 125 (25%) between 1-6 hours. The smallest hematoma growth was seen in those patients achieving target systolic BP early (≤1 hour) compared with later periods 1 to 6 hour, and >6 hours (p trend=0.029). Therefore, the results of this paper provide evidence that quick, intensive, and maintained systolic BP lowering provides the best protection against hematoma growth for 24 hours.

Concussion Symptoms and Return to Play Time in Youth, High School, and College American Football Athletes

There is a need in the literature for more extensive concussion data in athletes aged 5-21 years and how puberty may affect concussion-related outcomes. The purpose of this epidemiological study was to examine sport-related concussion outcomes, including symptoms and return to play, in youth, high school, and collegiate football athletes from 2012-2014. The authors identified 1429 sports-related concussions reported among youth, high school and college-level football athletes with a mean (SD) of 5.48 (3.06) symptoms. Return to play at least 30-days post concussion occurred in 15.3% of athletes and in 3.1% less than 24 hours after the concussion. Comparing the different age groups, a higher number of concussion symptoms were reported in high school athletes. More high school athletes and youth athletes returned to play within 30 days after injury compared to college athletes (odds ratio 2.89 for high school athletes and 2.75 for youth athletes). Early return to play less than 24 hours after injury was more common in youth athletes compared to high school athletes (odds ratio 6.23). Overall, the results of this study provide evidence that differences in concussion-related outcomes exist by age group, level of competition and may be attributable to genetic, biologic, and/or developmental differences or level-specific variations in concussion-related policies and protocols, athlete training management, and athlete disclosure.

Long-Term Risk for Device-Related Complications and Reoperations After Implantable Cardioverter-Defibrillator Implantation: An Observational Cohort Study

Early risks associated with implantable cardioverter-defibrillators (ICDs) may include hematoma formation, device malfunction, and lead problems. The long-term risk for complications and how patient and device characteristics at implantation influence this risk are poorly defined. The authors of this observational cohort study determined the long-term risk for ICD-related complications requiring reoperation or hospitalization and reoperation for reasons other than complications, and to assess associated patient and device characteristics in 1437 U.S. hospitals from 2006 to 2010. The authors found that there were 6.1 (95% CI: 6.0 to 6.2) ICD-related complications per 100 patient-years that required reoperation or hospitalization and 3.9 (CI, 3.8 to 4.0) reoperations per 100 patient-years for reasons other than complications. Overall, 10 patients had complications or reoperation per 100 patient-years of follow-up. Greatest risk for ICD-related complications was associated with younger age at implantation (65 to 69 vs. >85 years), receipt of a CRT with a defibrillator device versus a single-chamber device, female sex, and black race. These results help quantify in the literature the high rate of device-related complications and reoperation after ICD implantation.

Image: PD

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