Clinical Briefs

By Louis Kuritzky, MD

Treatment of Recent-Onset AF with the Pill-in-the-Pocket

Although chronic oral antiarrhythmic prophylaxis and catheter ablation both enjoy great success for preventing recurrences of atrial fibrillation (AF), some patients are not appropriate candidates for either method, especially patients with infrequent recurrences of AF. Oral flecainide (FLEC) and propafenone (PRO) are highly efficacious in restoring sinus rhythm as demonstrated for hospitalized patients with recent onset AF.

Alboni and colleagues studied the feasibility of patient-administered FLEC or PRO for patients (n = 210) who had successfully responded to emergency room treatment of recent onset AF (< 48 hours). Study participants who experienced symptomatic recurrences presumed to be AF (n = 165) were advised to self-administer PRO or FLEC within 5 minutes of onset of new palpitations.

Mean followup was 15 months. Drug self-administration was effective in resolving symptoms in 94% of episodes, with a mean time to resolution of approximately 2 hours. There was a concomitant dramatic decline in the need for emergency room visits compared with the year prior to the study.

These results show promise for self-administration of PRO or FLEC for persons with recent onset of AF who have previously responded in the emergency room to antiarrhythmic treatment. Because the list of exclusions in this trial was long, clinicians will want to familiarize themselves with the full details of appropriate inclusion and exclusion before considering such methodology for their own patients in non-research settings.

Alboni P, et al. N Engl J Med 2004;351: 2384-2391.

Antibody Responses after Intradermal Flu Vaccination

The year 2004 was unusual in reference to problematic shortages of influenza vaccine (FLUVAX), resulting in vaccine rationing. One of the methods that might reduce the actual volume of vaccine needed in any season would be intradermal vaccination, as opposed to the traditional IM route currently advocated for FLUVAX administration. Support for this method is predicated upon the observation that intradermal vaccine provides greater exposure to macrophages and dendritic cells than IM, and hence induces a similar serum antibody response, using less vaccine.

Belshe and associates studied the immunogenicity of intradermal FLU-VAX in 2 groups of adults: age 18-60, and age older than 60. The intradermal formulation they studied was 40% of the strength of standard IM vaccine, and was administered by a tuberculin syringe.

Amongst younger subjects, the immune responses of IM and intradermal administrations were essentially equivalent. In subjects older than 60 years, antibody titers were significantly lower than achieved by IM methodology, but were still sufficient to meet the criteria of the European Committee for Proprietary Medicinal Products that ensure vaccine adequacy. Conceivably, during times of vaccine shortage, administration of smaller volumes of FLU-VAX intradermally, especially to younger recipients, would be a rational choice.

Belshe RB, et al. N Engl J Med. 2004;351:2286-2294.

Isosorbide Dinitrate and Hydralazine in Blacks with HF

Neurohumoral modulators such as ACE inhibitors, angiotensin receptor blockers, beta blockers, and aldosterone have all shown meaningful benefit for patients with chronic heart failure (CHF). Retrospective analyses of trials including significant populations of black patients have suggested that this group, which appears to have less intense activation of the renin-angiotensin-aldosterone system in CHF than non-black comparators, enjoys a significant responsivity to administration of nitrates and hydralazine.

This trial was performed to investigate the impact of nitrates (specifically, isosorbide dinitrate titrated to 40 mg t.i.d.) and hydralazine (titrated to 75 mg t.i.d.) in patients with NYHA Class II-IV CHF already receiving standard therapy, which includes ACE inhibitors, angiotensin receptor blockers, beta blockers, spironolactone, and digoxin. The primary efficacy end point was a composite of death from any cause, first hospitalization for heart failure, and quality of life.

The study was terminated early because of a statistically significant favorable impact of active intervention, including a 43% relative reduction in death from any cause, 33% reduction in first hospitalization, and improvement in quality of life. Black patients already receiving standard therapy for CHF may benefit from the addition of both hydralazine and nitrates.

Taylor AL, et al. N Engl J Med. 2004;351:2049-2057.

Dr. Kuritzky, Clinical Assistant Professor, University of Florida, Gainesville, is Associate Editor of Internal Medicine Alert.