Title: Cardiovascular Screening in College Athletes With and Without Electrocardiography: A Cross-Sectional Study
Topic: Prevention/Vascular
Date Posted: 3/25/2010
Author(s): Baggish AL, Hutter AM Jr, Wang F, et al.
Citation: Ann Intern Med 2010;152:269-275.
Clinical Trial: No
Study Question: For purposes of screening college athletes before athletic participation, how do history and physical examination alone compare with a strategy including routine electrocardiography (ECG)?
Methods: Over a 3-year interval, 510 collegiate athletes at Harvard University (Cambridge, MA) who underwent preparticipation screening at the University Health Services were studied. Each participant underwent routine history, physical examination, ECG, and transthoracic echocardiography (TTE) to detect or exclude cardiac findings relevant to sports participation. TTE results were taken as the “gold standard” for disease presence. The performance of screening with history and physical examination only was compared with that of screening integrating history, examination, and ECG.
Results: Cardiac abnormalities relevant to sports participation risk were observed on TTE in 11 of 510 participants (prevalence, 2.2%; including mitral valve prolapse [n = 3], bicuspid aortic valve [n = 2], pulmonic stenosis [n = 1], left ventricular [LV] hypertrophy [n = 2], LV dilation [n = 2], and right ventricular dilation [n = 1]). Screening history and physical examination alone detected abnormalities in 5 of these 11 athletes (sensitivity 45.5%; 95% confidence interval [CI], 16.8-76.2% and specificity 94.4%; CI, 92.0-96.2%). ECG detected five additional participants with cardiac abnormalities (total 10 of 11 participants), with overall sensitivity of 90.9% (CI, 58.7-99.8%). However, including ECG reduced the specificity of screening to 82.7% (CI, 79.1-86.0%) and was associated with a false-positive rate of 16.9% (vs. 5.5% for screening with history and examination only). After further evaluation, athletic participation was restricted in three athletes (one each with TTE findings of pulmonic stenosis, LV hypertrophy, LV dilation).
Conclusions: Adding ECG to medical history and physical examination improves the overall sensitivity of preparticipation cardiovascular screening in athletes. However, this strategy is associated with an increased rate of false-positive results when current ECG interpretation criteria are used.
Perspective: The debate continues as to whether US amateur athletes should undergo a mandatory screening ECG (as is the policy in Italy, and subsequently adopted by the European Union) in addition to only screening history and physical examination (as is the long-standing US policy). On the surface, this study appears to add weight to the argument for routine preparticipation ECG. However, caveats abound, many of which were discussed in an accompanying editorial (Maron BJ, Ann Intern Med 2010;152:324-6). In addition:
The population of student athletes at Harvard might be anticipated to be poorly reflective of all amateur athletes in the US. (In this study, only 10% of screened athletes were black.) Because nonpathologic ECG abnormalities are far more prevalent in black than in white athletes, it could be anticipated that such benign but abnormal ECGs likely were under-represented in this study, and would have served to further reduce the specificity of the ECG.
Low test specificity and the associated high rate of false-positives is a major issue with the routine use of preparticipation ECG. The best-case scenario is that more money is spent to do more tests to prove that everything was OK to begin with. The worse (and probably more realistic) outcome is that amateur athletes are denied the ability to participate—including many with no underlying cardiac disease, and others with disease, but no prohibitive risk. In a country plagued by obesity, diabetes, and their various sequelae, physical activity should be encouraged not just in principle but in practice. Setting a low threshold for exclusion from athletics only will serve to worsen our obesity epidemic.
The authors used as a ‘gold standard’ for disease any abnormality of an echocardiogram. But of the 11 athletes with an ‘abnormal’ TTE, athletic participation was limited in only three (one of whom had an abnormal physical examination). If our societal goal is to detect any cardiac disease in any child or young adult, then intended athletic participation is impertinent, and screening should be instituted universally. If our goal is to detect disease that might pose a risk to the athlete, then the denominator in this study should have been at most three, not 11 students.
David S. Bach, M.D., F.A.C.C.
Title: A Critical Decrease in Dominant Frequency and Clinical Outcome After Catheter Ablation of Persistent Atrial Fibrillation
Topic: Arrhythmias
Date Posted: 3/24/2010
Author(s): Yoshida K, Chugh A, Good E, et al.
Citation: Heart Rhythm 2010;7:295-302.
Clinical Trial: No
Study Question: Is a critical decrease in the dominant frequency (DF) of persistent atrial fibrillation (AF) predictive of a clinical efficacy similar to that observed after termination of AF during radiofrequency ablation (RFA)?
Methods: Antral pulmonary vein isolation (APVI) followed by RFA of complex fractionated atrial electrograms (CFAEs) in the atria and coronary sinus was performed in 100 consecutive patients with persistent AF. The DF of AF in lead V1 and in the coronary sinus was determined by fast Fourier transform analysis at baseline and before termination of AF to identify a critical decrease in DF predictive of sinus rhythm after RFA. Multivariate logistic regression analysis was performed to identify the predictors of freedom from recurrent atrial arrhythmias after catheter ablation.
Results: A ≥11% decrease in DF had the highest accuracy in predicting freedom from atrial arrhythmias, with a sensitivity of 0.71 and a specificity of 0.82 (p < 0.001). At a mean follow-up of 14 ± 3 months after one ablation procedure, sinus rhythm was maintained off antiarrhythmic drugs in 8/35 (23%) and 20/26 (77%) patients with a <11% and ≥11% decrease in DF, respectively (p < 0.001). Sinus rhythm was maintained in 24/39 patients (62%) in whom RFA terminated AF. The duration of RFA and total procedure time were longer in patients with AF termination (95 ± 23 and 358 ± 87 minutes) than in patients with a <11% decrease in the DF (77 ± 16 and 293 ± 70 minutes) or ≥11% decrease in DF (80 ± 17 and 289 ± 73 minutes), respectively (p < 0.01). Among the variables of age, gender, left atrial diameter, duration of AF, left ventricular ejection fraction, duration of RFA, a ≥11% decrease in DF, and termination of AF, a ≥11% decrease in DF (odds ratio [OR], 9.89; 95% confidence interval [CI], 2.84-34.47) and termination during RFA (OR, 4.38; 95% CI, 1.50-12.80) were the only independent predictors of freedom from recurrent atrial arrhythmias.
Conclusions: The authors concluded that a decrease in the DF of AF by 11% in response to APVI and ablation of CFAEs was associated with a probability of maintaining sinus rhythm that was similar to that when RFA terminates AF.
Perspective: In this retrospective analysis of consecutive patients with persistent AF, patients who had a ≥11% decrease in the DF or termination of AF during ablation were more likely to remain in sinus rhythm than patients who remain in AF during RFA and have a lesser decrease in the DF. In fact, a reduction in the dominant frequency by 11% or more without termination of AF by catheter ablation was as predictive of a successful outcome as was termination of AF by RFA. The clinical utility of monitoring DF in real time to guide catheter ablation of AF requires further validation in prospective multicenter studies. Debabrata Mukherjee, M.D., F.A.C.C.