A randomized comparison of retrograde left-sided versus anterograde right-sided ablation of the atrioventricular junction.

BACKGROUND: Catheter ablation of the atrioventricular node (AVN) is an effective treatment for patients with symptomatic atrial fibrillation. This study compares the success rate, procedure time, radiation time, and complication rates of retrograde left-sided (LSA) and anterograde right-sided (RSA) AVN ablation in a randomised controlled trial. METHODS: Thirty-one patients undergoing AVN ablation were randomized to either LSA (15 patients) or RSA (16 patients). Crossover occurred after six unsuccessful radiofrequency (RF) applications. RESULTS: The LSA cohort had a mean age of 77.00 ± 5.17 and the RSA cohort was 79.44 ± 6.08 (p = .0240). There were five crossovers from LSA to RSA and there was one crossover from RSA to LSA. There was no significant difference in ablation time between LSA and RSA (210.40 ± 179.77 vs. 192.19 ± 130.29 seconds, p = .748). There was no significant difference in procedure time, fluoroscopy time, radiation dose, or number of RF applications between the two groups. There was 1 (6.67%) serious adverse event in the LSA group and 1 (6.25%) in the RSA group due to femoral hematomas requiring blood transfusion or intervention. There was no significant difference in patient-reported discomfort between LSA and RSA (16.43 ± 20.67 vs. 17.87 ± 28.08, p = .877). The study was stopped before full recruitment due to futility. CONCLUSIONS: Retrograde LSA of the AVN does not reduce RF applications, procedure time, or radiation exposure compared with conventional RSA and cannot be recommended as a first-line clinical approach.

Age-Related Changes in the Anatomy of the Triangle of Koch: Implications for Catheter Ablation of Atrioventricular Nodal Re-entry Tachycardia.

BACKGROUND: Atrioventricular nodal re-entrant tachycardia is the most common type of paroxysmal supraventricular tachycardia. We sought to assess whether important anatomic factors, such as the location of the slow pathway, proximity to the bundle of His, and coronary sinus ostium dimensions, varied with patient age, and whether these factors had an impact on procedural duration, acute success, and complications. METHODS: Baseline demographic and procedural data were collected, and the maps were analyzed. Linear regression models were performed to evaluate the associations between age and these anatomic variations. Associations were also assessed, with age categorized as being ≥ 60 years or < 60 years. RESULTS: The slow pathway was more commonly located in a superior location relative to the coronary sinus ostium in older patients. The location of the slow pathway moved in a superior direction by 1 mm for every increase in 2 years from the mean estimate of age. Additionally the slow pathway tended to be closer to the coronary sinus ostium in older patients, and the diameter of the ostium was larger in older patients. This resulted in longer procedure time, longer ablation times, and a greater need for long sheaths for stability. CONCLUSIONS: The location of the slow pathway becomes more superior and closer to the coronary sinus ostium with increasing age. Additionally, the coronary sinus diameter increases with age. These factors result in longer ablation and procedural times in older patients.

CONTEXTE: La tachycardie par réentrée nodale auriculoventriculaire est le type le plus fréquent de tachycardie supraventriculaire paroxystique. Nous avons voulu évaluer si des facteurs anatomiques importants, tels que l'emplacement de la voie lente, la proximité du faisceau de His et les dimensions de l'orifice du sinus coronaire (ostium), variaient avec l'âge, et si ces facteurs avaient un effet sur la durée de l'intervention, le succès à court terme et les complications. MÉTHODOLOGIE: Des données sur les caractéristiques démographiques initiales et l'intervention ont été recueillies, et les cartes obtenues ont été analysées. Des modèles de régression linéaire ont servi à déterminer les corrélations entre l'âge et ces variations anatomiques. Les corrélations ont aussi été évaluées selon des catégories d'âge, soit ≥ 60 ans et < 60 ans. RÉSULTATS: La voie lente a été repérée plus souvent dans un emplacement supérieur par rapport à l'orifice du sinus coronaire chez les patients plus âgés. L'emplacement de la voie lente s'était déplacé de 1 mm vers le haut pour chaque augmentation de 2 ans de l'estimation moyenne de l'âge. Par ailleurs, chez les patients plus âgés, la voie lente était généralement plus proche de l'orifice du sinus coronaire et le diamètre de l'orifice était élargi. Ces variations se sont traduites par une augmentation du temps d'intervention et d'ablation et par un besoin accru de longues gaines pour la stabilité. CONCLUSIONS: L'emplacement de la voie lente devient plus éloigné vers le haut et plus proche de l'orifice du sinus coronaire avec le vieillissement. De plus, le diamètre du sinus coronaire augmente avec l'âge. Ces facteurs entraînent des temps d'ablation et d'intervention plus longs chez les patients plus âgés.

The influence of age on heart rate variability during morning wakefulness.

OBJECTIVE: Early morning wakefulness is associated with a peak in cardiac events. The influence of ageing on cardiac regulation during this time is unknown. This cross-sectional study of healthy men and women (n = 40, 20-30 and >60 years) investigated the effect of age on heart rate variability (HRV) during morning versus evening wakefulness and sleep. METHODS: Stable electrocardiogram data during each wake period and sleep stage was analysed using power spectral analysis. HRV measurements were assessed using two (young, older) by two (male, female) ANOVAs with repeated measures on wake/sleep stage. RESULTS: Young adults experienced increased low-frequency power and low-frequency/high-frequency ratios during morning wakefulness versus slow wave sleep (p < 0.01). Older adults did not show any variation in any HRV variables across wake and sleep stages. All effects were independent of gender. INTERPRETATION: Older adults did not experience increased sympathetic dominance during morning wakefulness; thus in the older population, fluctuations in autonomic control, indicated by HRV measurements, are unlikely to account for increased occurrence of cardiac events at this time.

Excess pressure integral predicts cardiovascular events independent of other risk factors in the conduit artery functional evaluation substudy of Anglo-Scandinavian Cardiac Outcomes Trial.

Excess pressure integral (XSPI), a new index of surplus work performed by the left ventricle, can be calculated from blood pressure waveforms and may indicate circulatory dysfunction. We investigated whether XSPI predicted future cardiovascular events and target organ damage in treated hypertensive individuals. Radial blood pressure waveforms were acquired by tonometry in 2069 individuals (aged, 63±8 years) in the Conduit Artery Functional Evaluation (CAFE) substudy of the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT). Measurements of left ventricular mass index (n=862) and common carotid artery intima media thickness (n=923) were also performed. XSPI and the integral of reservoir pressure were lower in people treated with amlodipine±perindopril than in those treated with atenolol±bendroflumethiazide, although brachial systolic blood pressure was similar. A total of 134 cardiovascular events accrued during a median 3.4 years of follow-up; XSPI was a significant predictor of cardiovascular events after adjustment for age and sex, and this relationship was unaffected by adjustment for conventional cardiovascular risk factors or Framingham risk score. XSPI, central systolic blood pressure, central augmentation pressure, central pulse pressure, and integral of reservoir pressure were correlated with left ventricular mass index, but only XSPI, augmentation pressure, and central pulse pressure were associated positively with carotid artery intima media thickness. Associations between left ventricular mass index, XSPI, and integral of reservoir pressure and carotid artery intima media thickness and XSPI were unaffected by multivariable adjustment for other covariates. XSPI is a novel indicator of cardiovascular dysfunction and independently predicts cardiovascular events and targets organ damage in a prospective clinical trial.

Pocket-size hand-held cardiac ultrasound as an adjunct to clinical examination in the hands of medical students and junior doctors.

AIMS: While patient history taking and physical examination remain the cornerstones of patient evaluation in clinical practice, there has been a decline in the accuracy of the latter. Pocket-size hand-held echocardiographic (PHHE) devices have recently been introduced and could potentially improve the diagnostic accuracy of both medical students and junior doctors. The amount of training required to achieve optimal results remains a matter of debate. We hypothesized that the use of PHHE after limited training in the form of a tutorial can improve the clinical diagnosis even in the hands of medical students and inexperienced physicians. METHODS AND RESULTS: Five final-year medical students and three junior doctors without prior echocardiographic experience participated in a standardized 2 h PHHE bedside tutorial. Subsequently, they assessed 122 cardiology patients using history, physical examination, ECG and PHHE. Their final clinical diagnosis was compared against that of a consultant clinician's and also expert in echocardiography. A total of 122 PHHE were performed of which 64 (53%) by final-year medical students and 58 (47%) by junior doctors. Mean ± SD for diagnostic accuracy after history, physical examination, and ECG interpretation was 0.49 ± 0.22 (maximum = 1), whereas the addition of PHHE increased its value to 0.75 ± 0.28 (Z = -7.761, P<0.001). When assessing left ventricular systolic dysfunction by means of history and physical examination, specificity was 84.9% and sensitivity only 25.9%, whereas after including findings from PHHE, these figures rose to 93.6 and 74.1%, respectively. CONCLUSION: The use of PHHE after brief bedside training in the form of a tutorial greatly improved the clinical diagnosis of medical students and junior doctors, over and above history, physical examination, and ECG findings.

A novel fully automated method for mitral regurgitant orifice area quantification.

BACKGROUND: Effective regurgitant orifice area (EROA) in mitral regurgitation (MR) is difficult to quantify. Clinically it is measured using the proximal isovelocity surface area (PISA) method, which is intrinsically not automatable, because it requires the operator to manually identify the mitral valve orifice. We introduce a new fully automated algorithm, ("AQURO"), which calculates EROA directly from echocardiographic colour M-mode data, without requiring operator input. METHODS: Multiple PISA measurements were compared to multiple AQURO measurements in twenty patients with MR. For PISA analysis, three mutually blinded observers measured EROA from the four stored video loops. For AQURO analysis, the software automatically processed the colour M-mode datasets and analysed the velocity field in the flow-convergence zone to extract EROA directly without any requirement for manual radius measurement. RESULTS: Reproducibility, measured by intraclass correlation (ICC), for PISA was 0.80, 0.83 and 0.83 (for 3 observers respectively). Reproducibility for AQURO was 0.97. Agreement between replicate measurements calculated using Bland-Altman standard deviation of difference (SDD) was 21,17 and 17mm(2)for the three respective observers viewing independent video loops using PISA. Agreement between replicate measurements for AQURO was 6, 5 and 7mm(2)for automated analysis of the three pairs of datasets. CONCLUSIONS: By eliminating the need to identify the orifice location, AQURO avoids an important source of measurement variability. Compared with PISA, it also reduces the analysis time allowing analysis and averaging of data from significantly more beats, improving the consistency of EROA quantification. AQURO, being fully automated, is a simple, effective enhancement for EROA quantification using standard echocardiographic equipment.

Sleep architecture and attenuated heart rate response to arousal from sleep in patients with autonomic failure.

OBJECTIVE: To determine if patients with autonomic failure have increased sleep disturbances and if multiple system atrophy (MSA) and pure autonomic failure (PAF) patients have frequent arousals from sleep associated with an attenuated heart rate (HR) response compared to healthy volunteers. METHODS: With informed consent, 10 autonomic failure patients and 10 healthy volunteers were studied. Sleep disturbances were scored using standard criteria. Arousals were identified from stage 2 sleep and differences in the R-R interval between groups were tested using a mixed-model regression analysis. RESULTS: Three MSA and one PAF patient had obstructive sleep apnoea compared to one volunteer. One MSA and three PAF patients had periodic limb movements. One MSA patient had REM behaviour disorder. The autonomic patients had significantly reduced total sleep time (p=0.007) and sleep efficiency (p=0.003). The HR response to arousal was smaller in autonomic failure patients compared to volunteers during the early phase of the arousal (p=0.047), but not the later phase (p=0.67). CONCLUSION: Autonomic failure patients have increased sleep disturbances compared to healthy volunteers. The smaller HR response in autonomic failure patients suggests that an intact sympathetic nervous system is a key component of the HR response associated with arousal from sleep.