BACKGROUND: Few data describe the case burden of heart disease and cardiovascular risk factors relative to other conditions in urban Africans seeking primary health care. METHODS: A clinical registry captured data on 1311 consecutive primary care patients (99% African) from two primary care clinics in Soweto, South Africa. Those with suspected sub-clinical heart disease had more advanced car...

BACKGROUND: The molecular mechanisms of exercise training induced cardiovascular protection are poorly understood. There is growing evidence that reactive oxygen species may be involved in a number of these adaptations and that antioxidants may be used to investigate this effect. OBJECTIVE: To determine the effects of exercise training and/or antioxidant supplementation on myocardial endothe...

BACKGROUND: In contrast to patients with heart failure (HF) with reduced left ventricular ejection fraction (LVEF; HFREF) the prognostic role of heart rate (HR) and blood pressure (BP) in patients with HF and preserved LVEF (HFPEF) is not well known. The aim of this study was to characterize the relationship between HR and BP and outcomes in HFPEF and to compare it to HFREF. METHODS: The ass...

OBJECTIVE: The aim of this study was to quantify daytime symptoms in atrial fibrillation (AF) patients with and without sleep related breathing disorders (SRBD). BACKGROUND: SRBD are common in patients with AF but little is known about daytime symptoms among those with SRBD. METHODS: Patients with AF admitted to clinics of two tertiary referral hospitals for a variety of different cardiova...

OBJECTIVE: To describe physical function, leg complications and health-related quality of life (HRQOL) in the three months following extracorporeal membrane oxygenation (ECMO) pre- or post-heart transplantation (HTx). BACKGROUND: Little is known about functional recovery following ECMO before or after HTx. METHODS: A 2-year retrospective study in patients who received ECMO pre or pos...

BACKGROUND: With the recent advent of high-density (HD) 3-dimensional (3D) mapping, the utility of entrainment is uncertain. However, the limitations of visual representation and interpretation of these high-resolution 3D maps are unclear. OBJECTIVE: The purpose of this study was to determine the strengths and limitations of both HD 3D mapping and entrainment mapping during mapping of ri...

BACKGROUND: Evidence for epicardial-endocardial breakthrough (EEB) is derived from mapping inferences in patients with atrial fibrillation who may also have focal activations. OBJECTIVE: The purpose of this study was to investigate whether EEB could be discerned during stable right atrial (RA) macroreentry using high-density high-spatial resolution 3-dimensional mapping. METHODS: Mac...

BACKGROUND: Pulmonary vein isolation (PVI) is a well-established treatment of atrial fibrillation (AF), with contact force (CF)-sensing catheters joining 3-dimensional mapping systems and image integration as technological advancements over the last decade. OBJECTIVE: The purpose of this study was to analyze trends in radiation exposure for AF ablation over the last 12 years at our cente...

BACKGROUND: Early studies demonstrated relatively low success rates for pulmonary vein isolation (PVI) alone in patients with persistent atrial fibrillation (PeAF). However, the advent of new technologies and the observation that additional substrate ablation does not improve outcomes have created a new focus on PVI alone for treatment of PeAF. OBJECTIVE: The purpose of this study was to...

BACKGROUND: Chronic kidney disease (CKD) patients undergoing hemodialysis (HD) have a high risk of sudden cardiac death (SCD). A unique risk factor may be a longer interval between HD sessions (interdialytic period). Inherent in conventional HD (thrice-weekly) are two 48-hour short breaks (SIDP) and one 72-hour long break (LIDP) between HD sessions. OBJECTIVE: We used an implantable cardiac ...

BACKGROUND: Early repolarization (ER) with a horizontal ST segment (ST-h) and high-amplitude J waves in the inferior leads is associated with an increased risk of cardiac arrhythmic death. The effect of ethnicity and athletic status on this increased-risk ER pattern has not been established. Aboriginal Australian/Torres Strait Islander and Pacific Islander/Maori (non-Caucasian [non-C]) subject...

BACKGROUND: Hypertension is the most common modifiable risk factor associated with atrial fibrillation. OBJECTIVE: The purpose of this study was to determine the effects of blood pressure (BP) lowering after renal denervation on atrial electrophysiologic and structural remodeling in humans. METHODS: Fourteen patients (mean age 64 ± 9 years, duration of hypertension 16 ± 11 years, on 5 ± 2 ...

BACKGROUND: The impact of diffuse atrial fibrosis detected by T1 mapping on the clinical outcome after atrial fibrillation (AF) ablation is unknown. OBJECTIVE: This study aimed to validate and assess the impact of post-contrast cardiac magnetic resonance (CMR) imaging atrial T1 mapping on the clinical outcome after catheter ablation for AF. METHODS: CMR imaging was performed in 3 groups by...

BACKGROUND/OBJECTIVE: The purpose of this study was to characterize the association between the extent of left atrial electroanatomic remodeling in atrial fibrillation and the atrial fibrillation cycle length derived from lead V₁ of the surface ECG (V1AFCL). METHODS: Twenty-three patients in atrial fibrillation (AF) who presented for AF ablation underwent detailed electroanatomic mapping of ...

BACKGROUND: Circumferential pulmonary vein (PV) isolation is the cornerstone of catheter ablation for atrial fibrillation (AF); however, PV reconnection remains problematic. OBJECTIVE: To assess the impact of PV anatomy on outcome after AF ablation. METHODS: One hundred two patients with paroxysmal AF underwent cardiac magnetic resonance (60%) or computed tomography (40%) before AF ablatio...

BACKGROUND: Atrial fibrillation (AF) and systolic heart failure (HF) frequently coexist. Restoration of sinus rhythm by catheter ablation may result in a variable improvement in left ventricular (LV) function. Late-gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) imaging identifies irreversible structural change and may predict incomplete recovery of LV function. OBJECTIVE: T...

BACKGROUND: Catheter-tissue contact force (CF) determines radiofrequency (RF) ablation lesion size. Impedance changes during RF delivery are used as surrogate markers for CF. The relationship between impedance and real-time CF in humans remains unknown. OBJECTIVES: To determine whether impedance changes have predictive value for real-time CF during catheter ablation of atrial arrhythmias. M...

BACKGROUND: Catheter-tissue contact is important for effective lesion creation. OBJECTIVE: To assess the effect of respiration on contact force (CF) during atrial fibrillation and cavotricuspid isthmus (CTI)-dependent atrial flutter ablation. METHODS: Patients undergoing CTI ablation alone (n = 15) and pulmonary vein (PV) isolation alone (n = 12) under general anesthesia were recruited. Le...

BACKGROUND: Whether curative ablation can prevent progression of the atrial electroanatomic remodeling associated with atrial fibrillation (AF) is not known. OBJECTIVE: The purpose of this study was to determine whether successful radiofrequency ablation (RFA) of AF can prevent progression of the atrial substrate associated with AF. METHODS: Detailed right atrial electroanatomic maps from ...

BACKGROUND: The pulmonary veins (PVs) and the PV-LA (left atrium) junction are established sources of triggers initiating atrial fibrillation. In addition, they have been implicated in the maintenance of arrhythmia. OBJECTIVE: To undertake high-density electrophysiological characterization of the right superior PV-LA junction in humans. METHODS: Mapping was performed in 18 patients without...