IJCS | Volume 32, Nº4, July/August 2019

372 Mizzaci et al. Cardiopulmonary testing in patients with ICD Int J Cardiovasc Sci. 2019;32(4):368-373 Original Article Voss et al., 19 also demonstrated the safety of exercise testing in 400 patients with ICD. Of these, 200 patients performed a ramp protocol with an initial load of 0 W increased by 15 W every minute. Another 200 patients with ICD had a slightly modified ramp protocol with an initial workload of 0 W, but with capacity increased by 15 W every 2 minutes. The study population consisted mainly of patients with ischemic heart disease (63%). Atrial fibrillation was present in 16% of the individuals. Left ventricular ejection fractionwas 28%±8. In this cohort of patients, no sustained ventricular arrhythmia and no death occurred during or after the exercise testing. No inappropriate shock was observed. In this study, during CPET, the heart rate of patients did not reach the device therapy zones, most likely because theywere on negative chronotropic medications. Although safe heart rate limits were set for each patient, most tests were discontinued due to exhaustion before the heart rate limit was reached. Although the tests were discontinued at a heart rate below the ICDprogramming, it is observed that the mean RER was greater than 1.1, demonstrating maximum exercise. 6 In the current study, ventricular arrhythmias were observed in 29% of the individuals, including paired ventricular extrasystoles, ventricular bigeminism or nonsustained VT in 14.5%. However, there were no sustained ventricular arrhythmias that resulted in ICD therapy or inappropriate therapies. There was no cardiorespiratory arrest, hemodynamic instability during or immediately after exercise, or hospital admission due to cardiovascular complications. As an implication for clinical practice, CPET performed in patients with ICD was safe when performed in a hospital setting, with prior knowledge of device programming and respecting the heart rate of the therapy zones. The limitations of this study refer to the small number of patients included which, to some extent, is justified by the fear of referring patients with implantable devices to perform CPET, and because it is a retrospective study. As implications for future research, further prospective studies with larger samples should be conducted in order to obtain more robust results. Conclusion CPET in patients with ICD is a safe procedure in terms of severe acute complications, with low incidence of ventricular arrhythmia. Physicians performing CPET in these specific patients must be aware of ICD settings to limit heart rate below the first programmed therapy zone. There is no need for changes in device programming, such as deactivation of therapies, prior to this test. Author contributions Conception and design of the research: Mizzaci CC, Meneghelo RS, Mastrocola LE. Acquisition of data: Mizzaci CC, Fagundes TTS, Malafaia FL, Felicioni SP, Buglia S, Hossri CAC, Ferraz AS, Buchler RDD. Analysis and interpretation of the data: Mizzaci CC, Fagundes TTS, Malafaia FL, Felicioni SP, Buglia S, Hossri CAC, Ferraz AS, Buchler RDD, Meneghelo RS, Mastrocola LE. Statistical analysis: Mizzaci CC, Malafaia FL, Felicioni SP, Buglia S, Hossri CAC, Ferraz AS, Buchler RDD. Writing of the manuscript: Mizzaci CC, Fagundes TTS, Malafaia FL, Felicioni SP, Buglia S, Hossri CAC, Ferraz AS, Buchler RDD, Meneghelo RS, Mastrocola LE. Critical revision of the manuscript for intellectual content: Mizzaci CC, Fagundes TTS, Meneghelo RS, Mastrocola LE. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. Sources of Funding There were no external funding sources for this study. Study Association This study is not associated with any thesis or dissertation work. Ethics approval and consent to participate This article does not contain any studies with human participants or animals performed by any of the authors.