Adenosine versus intravenous calcium channel antagonists for tachycardia in adults

Background

Supraventricular tachycardia (SVT) is a common abnormal rhythm of the heart that results in a very rapid heartbeat. This rhythm problem usually occurs in otherwise healthy people, and common symptoms include palpitations, light-headedness, and chest pain. Occasionally, SVT may also cause confusion or loss of consciousness. SVT can sometimes be treated with simple physical manoeuvres such as forced breath holding. When simple manoeuvres fail, SVT can be treated in the emergency department with a variety of drugs. The two most commonly used drug types are adenosine and calcium channel antagonists (CCAs) (verapamil is the most frequently used drug in this class).

Study characteristics

This review compares effectiveness and side effects of adenosine and CCAs in terminating SVT episodes. We included in the review seven trials involving 622 patients. Evidence is current to July 2017.

Key results

Combined analysis of these trials showed no differences between adenosine and CCAs in successfully treating SVT. This finding is based on moderate-quality evidence. A temporary drop in blood pressure that did not require treatment was reported in only one of 152 study participants treated with CCAs, and low-quality evidence suggests that no patients treated with adenosine experienced low blood pressure. We have no data on length of stay in hospital nor on patient satisfaction.

Conclusions

Moderate-quality evidence shows no differences in effects of adenosine and calcium channel antagonists for treatment of SVT on reverting to sinus rhythm, and low-quality evidence suggests no differences in cases of hypotension. None of these trials examined patient preferences, which is an important factor in deciding which drug is the 'best' treatment.

Authors' conclusions: 

Moderate-quality evidence shows no differences in effects of adenosine and calcium channel antagonists for treatment of SVT on reverting to sinus rhythm, and low-quality evidence suggests no appreciable differences in the incidence of hypotension. A study comparing patient experiences and prospectively studied adverse events would provide evidence on which treatment is preferable for management of SVT.

Read the full abstract...
Background: 

People with supraventricular tachycardia (SVT) frequently are symptomatic and present to the emergency department for treatment. Although vagal manoeuvres may terminate SVT, they often fail, and subsequently adenosine or calcium channel antagonists (CCAs) are administered. Both are known to be effective, but both have a significant side effect profile. This is an update of a Cochrane review previously published in 2006.

Objectives: 

To review all randomised controlled trials (RCTs) that compare effects of adenosine versus CCAs in terminating SVT.

Search strategy: 

We identified studies by searching CENTRAL, MEDLINE, Embase, and two trial registers in July 2017. We checked bibliographies of identified studies and applied no language restrictions.

Selection criteria: 

We planned to include all RCTs that compare adenosine versus a CCA for patients of any age presenting with SVT.

Data collection and analysis: 

We used standard methodological procedures as expected by Cochrane. Two review authors independently checked results of searches to identify relevant studies and resolved differences by discussion with a third review author. At least two review authors independently assessed each included study and extracted study data. We entered extracted data into Review Manager 5. Primary outcomes were rate of reversion to sinus rhythm and major adverse effects of adenosine and CCAs. Secondary outcomes were rate of recurrence, time to reversion, and minor adverse outcomes. We measured outcomes by calculating odds ratios (ORs) and assessed the quality of primary outcomes using the GRADE approach through the GRADEproGDT website.

Main results: 

We identified two new studies for inclusion in the review update; the review now includes seven trials with 622 participants who presented to an emergency department with SVT. All included studies were RCTs, but only three described the randomisation process, and none had blinded participants, personnel, or outcome assessors to the intervention given. Moderate-quality evidence shows no differences in the number of people reverting to sinus rhythm who were treated with adenosine or CCA (89.7% vs 92.9%; OR 1.51, 95% confidence interval (CI) 0.85 to 2.68; participants = 622; studies = 7; I2 = 36%). Low-quality evidence suggests no appreciable differences in major adverse event rates between CCAs and adenosine. Researchers reported only one case of hypotension in the CCA group and none in the adenosine group (0.66% vs 0%; OR 3.09, 95% CI 0.12 to 76.71; participants = 306; studies = 3; I2 = 0%). Included trials did not report length of stay in hospital nor patient satisfaction.

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