High-dose adenosine for treatment of refractory paroxysmal supraventricular tachycardia

Adenosine response and failure to convert paroxysmal supraventricular tachycardia in the emergency department

BACKGROUND AND IMPORTANCE

Although adenosine is the recommended first-line therapy for patients with paroxysmal supraventricular tachycardia (SVT), it may fail to restore normal sinus rhythm. The factors associated with this failure remain unclear.

OBJECTIVE

To assess the response rate to adenosine and identify the factors causing adenosine failure in the management of paroxysmal SVT.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective study was conducted on adult patients diagnosed with paroxysmal SVT and treated with adenosine in the emergency departments of two large tertiary hospitals between June 2015 and June 2021.

OUTCOME MEASURE AND ANALYSIS

The primary outcome of the study was the patient response to adenosine, defined as the restoration of sinus rhythm documented in the patients' files. Backward-stepwise multivariate logistic regression was used to examine the predictors of adenosine failure based on the overall response to adenosine therapy.

MAIN RESULTS

A total of 404 patients, with a mean age of 49 (SD 15) years and a BMI of 32 (SD 8) kg/m 2 , and treated with adenosine for paroxysmal SVT, were included. Sixty-nine percent of patients were women. The overall response rate to any adenosine dose was 86% (n = 347). The baseline heart rate did not significantly differ between adenosine responders and non-responders (179.6 ± 23.1 vs. 183.2 ± 23.4). An association was observed between the history of paroxysmal SVT and successful response to adenosine (odds ratio = 2.08; 95% confidence interval 1.05-4.11).

CONCLUSION

The findings of this retrospective study suggested that the use of adenosine restored normal sinus rhythm in 86% of patients with paroxysmal SVT. Furthermore, a history of paroxysmal SVT and older age were associated with an increased chance of adenosine success.

Comparison of sinus conversion rates and body weights after 6 mg adenosine administration in supraventricular tachycardia

BACKGROUND

To evaluate the relationship between body weight and the success rate of supraventricular tachycardia (SVT) termination after an initial 6-mg adenosine administration.

METHODS

This retrospective observational study was conducted with medical records of patients who visited a single tertiary emergency department and underwent an electrophysiologic study with an SVT diagnosis. Patients under 18 years of age or those with SVT aberrancy, recurring SVT after radiofrequency catheter ablation, premedication of non-dihydropyridine calcium channel blocker, and signs of shock were excluded.

RESULTS

Data from 124 patients were collected. There were 69 women (55.6%); mean age, 49.7 years. The mean weight and height were 66.8 kg and 164.8 cm, respectively. Adenosine dose was 0.09 mg/kg. For the first sinus conversion (SC) success group (83 patients, 67%), the mean weight, height, and adenosine dose were 61.0 ± 11.5 kg, 161.9 ± 8.1 cm, and 0.10 ± 0.02 mg/kg. For the first SC failure group, these values were 78.4 ± 17.0 kg, 170.7 ± 8.9 cm, and 0.079 ± 0.02 mg/kg, respectively. To evaluate factors associated with the first SC, we performed bivariate logistic regression with weight (odds ratio [OR]: 1.093; 95% confidence interval [CI]: 1.045-1.144; P < 0.001) and height (OR: 1.071; 95% CI: 1.008-1.138; P = 0.027). Receiver operating characteristics curves and the cut-off values for adenosine dose and weight were 0.90 mg/kg and 66.5 kg with 71.1% sensitivity and 73.2% specificity (area under the curve: 0.814; 95% CI: 0.73-0.90; P < 0.001).

CONCLUSION

Weight and height were significant predictors of the first SC success rate among SVT patients. Consequentially, it is necessary to consider other adenosine administration methods, including increasing the initial drug dose or changing the flushing strategy after adenosine injection.

Potential and promising anticancer drugs from adenosine and its analogs

In recent years, many studies have shown that adenosine has efficacy for treating cancer. More importantly, some adenosine analogs have been successfully marketed to fulfill anticancer purposes. In this review, we summarize the anticancer effects of adenosine and its analogs in clinical trials and preclinical studies, with focus on their anticancer mechanisms. In addition, we link the anticancer activities of adenosine analogs with their structures through structure-activity relationship (SAR) analysis, and highlight additional promising anticancer drug candidates. We hope that this review will be of help in understanding the importance of adenosine and its analogs with anticancer activities and directing future research and development of such compounds.