EP News: Clinical N.A. Mark Estes, MD, FHRS From the Tufts Medical Center, Boston, Massachusetts.
Biventricular pacing for atrioventricular block and systolic dysfunction
Physiologic right ventricular adaptation in elite athletes of African and Afro-Caribbean origin
Curtis et al (N Engl J Med 2013;368:1585–1593, PMID 23614585) evaluated whether biventricular (Bi-V) pacing reduces mortality, morbidity, and adverse left ventricular (LV) remodeling in patients with a high percentage of right ventricular (RV) apical pacing. Patients with an indication for pacing with atrioventricular block, New York Heart Association class I, II, or III heart failure, and a LV ejection fraction of 50% or less were enrolled. Patients received a cardiac resynchronization pacemaker or implantable cardioverter-defibrillator and were randomly assigned to standard RV or Bi-V pacing. The primary outcome was the time to death from any cause, an urgent care visit for heart failure, or a 15% or more increase in the LV endsystolic volume index. In 691 randomized patients, the primary outcome occurred in 190 of 342 (55.6%) patients with RV pacing as compared with 160 of 349 (45.8%) with Bi-V pacing. Patients randomized to Bi-V pacing had a significantly lower incidence of the primary outcome than those with RV pacing (HR 0.74; P ≤ .05). The authors conclude that Bi-V pacing is superior to RV pacing in patients with atrioventricular block, LV systolic dysfunction, and New York Heart Association class I–III heart failure.
Zaidi et al (Circulation 2013;127:1783–1792, PMID 23538381) evaluated right ventricular (RV) remodeling and electrocardiographic changes in black athletes. Between 2006 and 2012, 300 consecutive black athletes (BAs; n ¼ 243, men) from 25 sporting disciplines were evaluated by using electrocardiography and echocardiography. Results were compared with 375 white athletes (WAs) and 153 sedentary controls (n ¼ 69, black). There were no ethnic differences between RV parameters in controls. Both BAs and WAs exhibited greater RV dimensions than did controls. RV enlargement compatible with diagnostic criteria for arrhythmogenic right ventricular cardiomyopathy (ARVC) was frequently observed (right ventricular outflow tract [RVOT]1 ≥ 32 mm; 45.0% of BAs and 58.5% of WAs). Anterior T-wave inversion was present in 14.3% of BAs compared to 3.7% of WAs (P o .001). Marked RV enlargement with concomitant anterior T-wave inversion was observed in 3.0% of BAs compared to 0.3% of WAs (P ¼ .005). Further investigation did not diagnose ARVC in any athlete. The authors conclude that physiologic RV enlargement is commonly observed in BAs as well as WAs. In the context of frequent electrocardiographic repolarization anomalies in BAs, the potential for erroneous diagnosis of ARVC is considerably greater in this ethnic group.
Cryoballoon ablation of pulmonary veins for paroxysmal atrial fibrillation Packer et al (J Am Coll Cardiol 2013;61:1713–1723, PMID 23500312) assessed the safety and effectiveness of cryoballoon ablation (CA) designed to achieve single-delivery pulmonary vein (PV) isolation. Patients with symptomatic paroxysmal AF and previously failed therapy with ≥1 antiarrhythmic drug underwent 2:1 randomization to either CA (n ¼ 163) or drug therapy (n ¼ 82). CA produced acute isolation of 3 or more PVs in 98.2% and all 4 PVs in 97.6% of the patients. PV isolation was achieved with the balloon catheter alone in 83%. At 12 months, treatment success was 69.9% (114 of 163) of the patients treated with CA compared to 7.3% of the patients treated with antiarrhythmic drug (absolute difference 62.6%; P o .001). Twenty-nine of 259 (11.2%) procedures were associated with phrenic nerve palsy with a resolution of 25 of these by 12 months. Patients treated with CA had significantly improved symptoms at 12 months. The authors conclude that CA is a safe and effective alternative to antiarrhythmic medication for the treatment of patients with symptomatic paroxysmal AF. Address reprint requests and correspondence: Dr N.A. Mark Estes, Tufts Medical Center, 800 Washington St, Boston, MA 02111. E-mail address:
[email protected].
1547-5271/$-see front matter
Quality-of-life assessment in the randomized PROTECT AF trial of patients at risk for stroke with nonvalvular atrial fibrillation Alli et al (J Am Coll Cardiol 2013;61:1790–1708, PMID 23500276) assessed quality of life (QoL) in patients enrolled in the PROTECT AF trial, which had demonstrated that in patients with nonvalvular atrial fibrillation and CHADS2 score ≥1, a left atrial appendage closure device is noninferior to long-term warfarin for stroke prevention. By using the health survey measurement tool, the authors obtained QoL at baseline and 12 months in 547 patients in the PROTECT AF trial (361 patients treated with a device and 186 patients treated with warfarin). In patients treated with the device, the total physical score improved in 34.9% and was unchanged in 29.9% compared to patients treated with warfarin, in whom 24.7% were improved and 31.7% were unchanged (P ¼ .01). Mental health improvement occurred in 33.0% of the device group compared to 22.6% in the warfarin group (P ¼ .06). There was a significant improvement in QoL in patients randomized to device for total physical score, physical function, and in physical role limitation compared to controls. The authors conclude that patients with atrial fibrillation at risk for stroke treated with left atrial appendage closure have favorable QoL changes at 12 months compared to patients treated with warfarin.
http://dx.doi.org/10.1016/j.hrthm.2013.05.004