Long-Term Sinus Rhythm Stability after Intraoperative Ablation of Permanent Atrial Fibrillation

Introduction: Short‐ and medium‐term sinus rhythm (SR) rates after intraoperative radiofrequency ablation to treat permanent atrial fibrillation (AF) are well documented. Is rhythm success stable during a long‐term follow‐up? Methods and Results: A total of 130 patients who had undergone intraoperative radiofrequency cooled‐tip endocardial ablation (SICTRA) of permanent AF (mean AF duration 6±5 years) concomitant to open heart surgery more than 3 years ago were followed up using electrocardiogram (ECG), Holter‐ECG, and echocardiography and compared with 12‐month follow‐up data. In 55% of patients, only the left atrium and in 45%, both atria were treated using SICTRA. Mitral valve replacement was performed in 21, mitral valve reconstruction in 25, aortic valve replacement in 13, CABG procedures in 51 (including 11 patients with additional mitral valve surgery), and complex procedures in 20 patients. Sixty‐nine percent of patients (90/130) were in stable SR after a median period of 48 months, whereas 28% (36/130) were in AF and 3% (4/130) were in atrial flutter. In between the 12‐month follow‐up and the long‐term follow‐up, seven patients converted to AF after having documented SR, two patients converted to typical right atrial flutter after being in SR, and two patients from AF to left atrial macroreentry. After left and biatrial SICTRA, SR rates were comparable (73% vs 66%, P = 0.45). Echocardiography revealed 73% of patients in SR to have effective left atrial contraction. Conclusions: SICTRA restores long‐term stable SR in 69% of all patients. Nine percent of patients reconverted back to atrial arrhythmia after having documented SR at 12 months.     

Prospective cross-over comparisons of three low-density lipoprotein (LDL)-apheresis methods in patients with familial hypercholesterolaemia

We prospectively compared effectiveness, selectivity and biocompatibility of three LDL-apheresis methods, immunoadsorption (IMAL), dextran sulphate adsorption (DSAL) and heparin-induced extracorporeal LDL precipitation (HELP). Seven patients with familial hypercholesterolaemia were treated twice with each method in random sequence. Reduction in atherogenic lipoproteins was without significant difference: LDL −60% to −75%, VLDL −20% to −30%, triglycerides −20% to −42%. High-density lipoprotein (HDL)-cholesterol was reduced by IMAL only (−27%, P <0.05); DSAL and HELP did not decrease HDL. Total plasma protein reduction was 13–15% with each method, indicating unselectivity. Albumin was significantly decreased by IMAL (−15%, P <0.05) but not by the other methods. DSAL and HELP reduced fibrinogen (−40%, −58%, P <0.0001) and other clotting factors. IMAL had almost no effect on coagulation. The white blood cell count did not change. C3 and C4 complement were decreased (−20% to −46%) by all methods. C5a complement did not increase in systemic blood, but was increased in the extracorporeal circulation of IMAL (+200%) and HELP (+150%). Plasma PMN elastase rose in all methods (+200%) indicating neutrophile degranulation. In conclusion, in this short-term study of a small patient population, effectiveness of the three LDL-apheresis methods was similar, but selectivity and biocompatibility were different. The therapeutic relevance of these differences for long-term treatment remains to be elucidated.     

Orthodromic and Antidromic Pacemaker Circus Movement Tachycardia

Pacemaker circus movement tachycardia (PCMT) during DDD pacing is usually sustained by retrograde natural and antegrade electronic atrioventricular (AV) conduction. As PCMT is often initiated by a ventricular premature beat (VPB) one method of its prevention is the programming of an atrial stimulus synchronously following a ventricular extrasystole. A patient is described with preserved antegrade, but without retrograde, i.e., VA, conduction. The optional pacemaker mode of synchronous atrial stimulation following a VPB caused an unusual PCMT sustained by retrograde electronic and antegrade natural AV conduction. This PCMT is similar to a natural reentry tachycardia, the most common variety of which (based on retrograde conduction) is termed antidromic and that which we describe is orthodromic.     

What is the Ideal Pulse Frequency for Skeletal Muscle Stimulation After Cardiomyoplasty?

Routinely the latissimus dorsi (LD) muscle is stimulated with bursts of pulses at 30 pulses/sec after Cardiomyoplasty to assist the failing heart. At a lower pulse frequency the contractile force decreases and at higher frequencies the energy demand of the pacemaker increases rapidly. We investigated the effect of the stimulus frequency variation on contractile force in untrained LD muscles and in muscles after 12 weeks of continuous cyclic electrical stimulation. In six dogs, two electrodes (Medtronic SP5528) were implanted in the left LD muscle together with an ltrel muscle stimulator. The LD muscle was stimulated with 30 pulses/sec in bursts to deliver initially 30 and after 10 weeks 80 contractions per minute. Both before and after training of the LD muscle maximum force was observed by stimulating with a frequency of 36 to 130 pulses/sec in a burst. However, training induced a shift in the steep part of the force-frequency relation to lower frequencies. In particular, at 15 pulses/sec 60% of the maximal force was obtained in contrast to 40% before training. A fatigue test of 8 minutes duration was performed specified by 100 bursts/min and a burst duration of 0.25 sec at pulse frequencies of 30, 36, 50, and 85 pulses/sec. The contractile force decreased significantly during the course of the test at all frequencies. However, the force obtained with 30 pulses/sec stimulation was lower during the initial phase and approximately 10% higher at the end of the fatique test as compared to 36, 50, and 85 pulses/ sec stimulation. We conclude that when the LD muscle is demanded to assist afailing heart by contracting 100 times a minute, pulse trains with a frequency of 30 pulses/sec deliver a near maximal contractile force (80%) and are significantly less fatiguing in comparison to pulse (rains at higher frequencies. This indicates that LD muscle stimulation after Cardiomyoplasty should be performed at 30 pulses/sec.     

Confirmation and further regional assignment of aminoacylase 1 (ACY-1) on human chromosome 3 using a simplified detection method

An improved method for the detection of aminoacylase-1 (ACY-1) is described. Data from human-rodent interspecific hybrids confirm the assignment of ACY-1 to human chromosome 3. The most likely site for ACY-1 appears to be 3p21 to 3pter. The enzyme ACY-1 hydrolyses both acetyl methionine and acetyl glutamate.     

Lucid dreaming: an age‐dependent brain dissociation

The current study focused on the distribution of lucid dreams in school children and young adults. The survey was conducted on a large sample of students aged 6–19 years. Questions distinguished between past and current experience with lucid dreams. Results suggest that lucid dreaming is quite pronounced in young children, its incidence rate drops at about age 16 years. Increased lucidity was found in those attending higher level compared with lower level schools. Taking methodological issues into account, we feel confident to propose a link between the natural occurrence of lucid dreaming and brain maturation.