Zeitschrift für Kardiologie
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Randomized Controlled Trial Comparative Study Clinical Trial
[Nocturnal oxygen administration and cardiac arrhythmias during Cheyne-Stokes respiration in patients with heart failure].
Cheyne-Stokes respiration (CSR) is common during sleep in patients with severe congestive heart failure. It is not clear, if there is a relation between CSR and arrhythmias. Therefore in this study the impact of the nocturnal CSR on ventricular arrhythmias and the heart rate, as well as the influence of nasal nocturnal oxygen on CSR and sleep was studied. ⋯ Due to the high day-today variability these differences were not significant, but the decrease of average nocturnal heart rate with oxygen was (71 +/- 14 vs 68 +/- 14/min; p < 0.05). In conclusion, nocturnal oxygen causes a reduction of CSR, an improvement of sleep and a decrease of arousals. A significant reduction of arrhythmias by nocturnal oxygen could not be proved.
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Comparative Study
[Comparison of active and passive fixation of steroid emitting atrial electrodes].
Steroid-eluting screw-in leads (CapSure Fix 4068, Medtronic; n = 14) were compared to the same lead as a J-shaped tined electrode (CapSure SP 4524, Medtronic; n = 27, implanted in the atrium in patients receiving dual-chamber pacemakers. Follow-up were at discharge and after 1 month. Implantation (screw-in lead: 84 +/- 18 min; tined lead: 81 +/-29 min) and fluoroscopy times (screw-in lead: 7.3 +/- 4.9 min; tined lead 9.2 +/- 7.0 min) were similar in the two groups. At implant, P-wave amplitudes were similar with 4.8 +/- 1.6 mV (screw-in lead) and 4.0 +/- 2.6 mV (tinted lead), respectively. Compared to tined leads, the screw-in leads had higher pacing thresholds at 0.5 ms pulse duration (screw-in lead: 0.74 +/- 0.32 V; tined lead: 0.55 +/- 0.15 V; p = 0.02) as well as higher impedance (screw-in lead: 566 +/- 93 ohms; tined lead: 470 +/- 99 ohms; p = 0.01). Pulse duration thresholds at 2.5 V pulse amplitude were neither different at discharge (screw-in lead: 0.07 +/- 0.04 ms; tined lead: 0.06 +/- 0.05 ms) nor after 1 month (screw-in lead: 0.09 +/- 0.04 ms; tined lead: 0.06 +/- 0.06 ms). P-wave amplitudes > or = mV were observed at discharge in 14/14 (screw-in lead) 21/27 patients (tined lead), respectively, and after 1 month in 13/14 (screw-in lead) and 22/27 (tined lead) patients, respectively. Impedance of the screw-in lead was significantly higher with 693 +/- 84 ohms at discharge and 691 +/- 79 ohms after 1 month compared to the tined lead with 520 +/- 81 and 574 +/- 62 ohms (p = 0.001). No lead dislodgment was reported during follow-up. ⋯ For the studied steroid-eluting leads active and passive fixation had neither at implantation nor during 1-month follow up any influence on P-wave amplitude. At similar pulse duration thresholds, impedance of the screw-in lead was significantly higher than for the tined lead. Higher impedance additionally reduces pacing current, if similar pacing impulses are delivered.
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The first report about successful radio frequency ablation of a right-posterior-septal accessory pathway appeared in 1986. Since then, the technology of both guidable ablation catheters and radio frequency generators has been considerably improved in an initially clinical-experimental phase. At the same time, electrophysiologists were equally able to enlarge their knowledge in the field of signal characteristics of arrhythmogenic substrates. ⋯ The only exception relates to the ablation of the AV node at accurate diagnosis for pacemaker implantation (VVIR; DDDR switch mode) which has become part of routine therapy, although, of course, atrial fibrillation itself or necessary anticoagulation cannot be abolished. Thus, our center shows a success rate of 98% in treating 117 patients by this method. First promising reports are available describing the attempt of AV node modification in the posterior nodal part with the goal of reducing the ventricular rate in atrial fibrillation.
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Adenosine has potent cardiac electrophysiologic effects including a negative chronotropic action on the sinus node and a predominant negative dromotropic action on the AV node. The latter property has mainly led to the use of adenosine as antiarrhythmic agent for the acute management of paroxysmal supraventricular tachycardia (PSVT) mediated by a reentrant mechanism involving the AV node. The effects of adenosine are dose-dependent and of very short duration since the half-life is less than 10s. ⋯ Adenosine is helpful to detect or to increase preexcitation which is important for planning a catheter ablation procedure since the preexcitation pattern allows to localize the accessory pathway. Since the action of adenosine usually does not alter the accessory pathway conduction it is also useful for control ablation efficacy noninvasively in terms of antegrade conduction and during ventricular pacing for the retrograde conduction. Further evaluation and research is necessary for better understanding of adenosine action on the human atrial electrophysiology since it provokes atrial fibrillation in some patients, and of adenosine action on the different pathways in AV nodal reentrant tachycardias and some accessory pathways with decremental (AV nodal-like) conduction properties.
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Severe congestive heart failure and cardiogenic shock don't resemble a homogeneous clinical picture, but a syndrome that is based on very different etiologies. What all the etiologies have in common is the inadequate peripheral O2-supply to essential organs with or without signs of severe pulmonary congestion up to pulmonary edema. For prognosis and therapy is a fast diagnostical clarification of the causes crucial. ⋯ First results give rise to optimism to effectively reduce the mortality of congestive heart failure. The combination of these new pharmacological possibilities with interventional transcutaneous applicable assist-systems (aortic counterpulsationpump IABP, hemopump, transcutaneous heart-lung-machine) as well as the transitory application of an artificial heart (Novacor) can possibly increase the success of these therapeutic strategies. So far there are no convincing results shown in the world literature.