Lorne J . Gula

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BACKGROUND Cyclic variation of the heart rate is observed during apneic spells in obstructive sleep apnea (OSA). We hypothesized that autonomic changes would affect frequency-domain measures of heart rate variability (HRV). METHODS We studied 20 patients (15 men, 5 women, mean age 47.2 +/- 12.2 years) with suspected OSA undergoing overnight(More)
OBJECTIVES We hypothesized an ablation strategy directly targeting muscle bundles might demonstrate functionally distinct "routes" of conduction, potentially shortening ablation times. BACKGROUND Pathological study demonstrated that the cavotricuspid isthmus is composed of distinct anatomically defined bundles, many with intervening gaps of connective(More)
BACKGROUND Cardiac arrest without evident cardiac disease may be caused by subclinical genetic conditions. Provocative testing to unmask a phenotype is often necessary to detect primary electrical disease, direct genetic testing, and perform family screening. METHODS AND RESULTS Patients with apparently unexplained cardiac arrest and no evident cardiac(More)
BACKGROUND Approximately 30% of patients undergoing pulmonary vein isolation (PVI) for atrial fibrillation (AF) have clinical recurrence of AF, and a great majority of these patients have recovery of vein conduction. Adenosine can be associated with acute recovery of conduction to the pulmonary veins immediately after isolation. However, it is not known(More)
BACKGROUND The maximum voltage-guided (MVG) approach to ablation for atrial flutter targets high-amplitude signals along the cavotricuspid isthmus (CTI). It is based on the observation that the isthmus is often composed of bundles of conducting tissue and the hypothesis that these bundles manifest as high-amplitude electrograms, providing targets for(More)
BACKGROUND The study was conducted to compare relative safety and efficacy of pulmonary vein antrum isolation (PVAI) using intracardiac echocardiographic guidance and circumferential pulmonary vein ablation (CPVA) for atrial fibrillation (AF) using radiofrequency energy. METHODS AND RESULTS Sixty patients (81% men; 81% paroxysmal; age, 56+/-8 years)(More)
BACKGROUND Syncope may be the result of primary bradycardia or tachycardia, vasovagal syncope, or noncardiac syncope. Risk factors and outcome scores to predict prognosis in patients with syncope have been developed. Although these correlate with morbidity and mortality in patients with syncope, their relationship with the mechanism of syncope has not been(More)
BACKGROUND The clinical diagnosis of long-QT syndrome (LQTS) remains challenging when ECG abnormalities are borderline or intermittent. Despite issues with access, cost, and heterogeneity of LQTS mutations, genetic testing remains the diagnostic gold standard for diagnosis of LQTS. We sought to develop a provocative testing strategy to unmask the LQTS(More)
BACKGROUND Scar signal quantification using late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) identifies patients at higher risk of future events, both in ischemic cardiomyopathy (ICM) and nonischemic dilated cardiomyopathy (DCM). However, the ability of scar signal burden to predict events in such patient groups at the time of referral for(More)
OBJECTIVES We sought to evaluate the impact of the left ventricular (LV) pacing site on hemodynamic response to cardiac resynchronization therapy (CRT). BACKGROUND CRT reduces morbidity and mortality in heart failure patients. However, 20% to 40% of eligible patients may not fully benefit from CRT device implantation. We hypothesized that selecting the(More)