The effect of optimal medical therapy on 1-year mortality after acute myocardial infarction.

OBJECTIVES: Five drug classes have been shown to improve the prognosis of acute myocardial infarction in clinical trials: aspirin, beta-blockers, statins, renin angiotensin system (RAS) blockers and thienopyridines. We aimed to assess whether the benefits of combining these drugs (termed optimal medical therapy, OMT), will result in a reduction of mortality in clinical practice. DESIGN: Nationwide registry SETTING: Hospitals with a cardiology unit or internal medicine department. PATIENTS: 5353 patients with acute myocardial infarction. At hospital discharge 89% received aspirin, 90% beta-blockers, 84% statins, 81% RAS blockers, 70% a thienopyridine and 46.2% OMT. INTERVENTIONS: Pharmacotherapy MAIN OUTCOME MEASURES: OR with 95% CI for mortality from myocardial infarction were calculated and adjusted for patient risk at baseline. RESULTS: Total mortality was reduced by 74% in patients receiving OMT (adj OR 0.26; 95% CI 0.18 to 0.38) versus patients receiving one or no drug. This was consistent in subgroups defined by STEMI/NSTEMI, diabetes and gender. Mortality was also reduced in patients receiving 2-4 drugs (adj OR 0.49; 95% CI 0.35 to 0.68), diabetic patients being the only subgroup with no significant effect. Analyses on the relative importance of either component revealed that withdrawal of beta-blockers (adj OR 0.63; 95% CI 0.34 to 1.16) and/or a combination of aspirin/clopidogrel (adj OR 0.59; 95% CI 0.20 to 1.17) abolished the risk reduction conferred by OMT. CONCLUSIONS: OMT over 1 year was associated with a significantly lower mortality of patients with acute myocardial infarction in clinical practice. However OMT is provided to less than half of eligible patients leaving room for substantial improvement.

[Reduction of in-hospital mortality and improved secondary prevention after acute myocardial infarction. First results from the registry of secondary prevention after acute myocardial infarction (SAMI)]. / Rückgang der Krankenhaus-Sterblichkeit und verbesserte Sekundärprävention nach akutem Myokardinfarkt. Erste Ergebnisse des SAMI-Registers.

BACKGROUND AND OBJECTIVE: In hospital mortality of acute myocardial infarction (AMI) has been reduced due to the availability of better therapeutic strategies. But there is still a gap between mortality rates in randomised trials and daily clinical practice. Thus, it was aim of the present registry to document the course and outcome of patients with AMI and to improve patient care by implementing recent guidelines. PATIENTS AND METHODS: In a nationwide registry study in hospitals in Germany with a cardiology unit or an internal medicine department data on consecutive patients were recorded for six to twelve months at admission, discharge and during a follow-up of one year. RESULTS: From 02/2003 until 10/2004 a total of 5,353 patients with acute myocardial infarction (65.7 % male, mean age of 67.6 +/- 17.7 years; 55.1 % of them with ST elevation myocardial infarction (STEMI) were included in the registry. Of the patients with STEMI, 76.6 % underwent acute intervention, 37.1 % had thrombolysis, 69.7 % percutaneous transluminal coronary angioplasty (PTCA). 40.0 % of those with non-Stemi (NSTEMI) had an acute intervention, 6.6 % thrombolysis, 73.5 % PTCA. Recommended secondary prevention consisted of ASS (93.2 %), beta-blockers (93.0 %), CSE-inhibitors (83.5 %), ACE-inhibitors (80.9 %) and clopidogrel (74.0 %). In-hospital mortality was 10.5 % (STEMI) and 7.4 % (NSTEMI). CONCLUSION: The 9 % mortality among patients with acute myocardial infarction treated in the hospitals participating in the SAMI registry is low compared to that in similar collectives. The high number of patients who had thrombofibrinolysis and coronary interventions as well as the early initiation of drug therapy contributed to these results. Medical treatment in the prehospital phase of these patients remains still insufficient and to a substantial extent contributes to the mortality of acute myocardial infarction.

Rejection of atrial sensing artifacts by a pacing lead with short tip-to-ring spacing.

AIMS: The ability of a new pacing lead design, with a 10 mm tip-to-ring spacing, to facilitate rejection of sensed far field R-waves and myopotentials was evaluated. METHODS AND RESULTS: Measurements were performed in 66 patients. The occurrence of far field R-wave sensing and myopotential sensing was determined by means of the surface ECG and the ECG markers provided by the pacemaker. At an atrial sensitivity of 0.25 mV and an atrial blanking of 50 ms far field R-wave sensing was observed in 12 patients (18.2%) and at an atrial sensitivity of 1.0 mV no far-field R-wave sensing was observed. Myopotentials were sensed in 3 patients. In all patients the measured P-wave amplitude was at least twice the estimated amplitude of the far field R-wave at an atrial blanking of 50 ms. CONCLUSION: The results from this study show that a small tip-to-ring spacing allows for programming of a high atrial sensitivity and short atrial blanking with an acceptably low risk for atrial artifact sensing.

Reduction of the pace polarization artefact for capture detection applications by a tri-phasic stimulation pulse.

This study investigated the ability to minimize pace polarization artefacts (PPA) by adjusting the post-stimulus pulse duration of a tri-phasic stimulation pulse. Adjustment of the stimulation pulse was enabled by downloading special study software into an already implanted pacemaker. Tests were performed in a total of 296 atrial leads and 311 ventricular leads. Both chronic and acute leads were included in the study. Statistically significant differences were found in the initial PPA (without any adjustment of the stimulus pulse) between atrial and ventricular leads. In addition, significant differences were observed among various lead models with respect to changes over time in the initial ventricular PPA. Successful PPA reduction was defined as a reduction of the PPA below 0.5 mV for atrial leads and below 1 mV for ventricular leads. Results show a success rate for ventricular and atrial PPA reduction of 97.8% and 98.7%, respectively. Threshold tests showed that after reduction of the PPA loss of ventricular capture can be reliably detected. However, atrial threshold tests showed many false positive evoked response detections. In addition, unexpectedly high evoked response amplitudes were observed in the atrium after reduction of the PPA. Results from additional measurements suggest that these high atrial evoked response amplitudes come from the influence of the input filter of the pacemaker.

Autocapture compatibility in patients with the MembraneEX lead and Affinity pulse generators.

The first Autocapture generation worked well with all recommended leads. The newer Autocapture generation provides a more sensitive resolution for evoked response testing and its implementation in a dual-chamber device. The purpose of the study was to evaluate the performance of the Affinity SR/DR pacemaker with the new Autocapture algorithm in combination with the small surface area pacing lead MembraneEX in 129 patients. Autocapture ventricular threshold, sensing threshold, lead impedance, evoked response (ER) and polarization signals were determined at implantation and discharge, as well as after 1 and 3 months. Autocapture recommendation rate was based on the ER sensitivity test. The median pacing threshold was 0.38, 0.50, 0.75, 0.75 V at implant, discharge, 1 and 3 months post-implant, respectively. The respective data for median lead impedance were 744, 605, 649 and 691 ohms; median sensing threshold was 12.5 mV at all visits. The median ER amplitude was 9.0, 10.1, 9.9 and 10.1 mV and the median polarization signal 0.39 mV at all visits. The frequency of recommended Autocapture activation was 98.3%, 99.2%, 98.3% and 96.2% of all patients at implant, at discharge, 1 and 3 months post-implant respectively. In conclusion, the studied pulse generator enabled, in combination with this pacing lead, in >95% of all patients activation of Autocapture.

Electrophysiological performance of a bipolar membrane-coated titanium nitride electrode: a randomized comparison of steroid and nonsteroid lead designs.

The aim of this multicenter study was to investigate the performance of a new cardiac pacemaker lead with a titanium nitride cathode coated with a copolymer membrane. In particular, the electrophysiological effect of steroid dissolved in this ion-exchange membrane was evaluated by randomized comparison. Ninety-five patients were randomized either to the 1450 T (n = 51) or the 1451 T ventricular lead (n = 45) and received telemeteral VVI(R) pacemakers with identical diagnostic features. Both leads were bipolar, were passively affixed, and had a porous titanium nitride tip with a surface area of 3.5 mm2. The only difference between the two electrodes was 13 micrograms of dexamethasone added to the 1450 Ts membrane coating. Voltage thresholds (VTH) at pulse durations of 0.25, 0.37, and 0.5 ms, lead impedance, and sensing thresholds were measured at discharge, 2 weeks, 1 month, 3 months, and 6 months after implantation. Mean amplitude and the slew rate from three telemetered intracardiac electrograms, chronaxie-rheobase product, and minimum energy consumption were calculated. After a 6-month follow-up, mean voltage thresholds of 0.65 +/- 0.20 V and 0.63 +/- 0.34 were achieved for the 1450 T lead and 1451 T lead, respectively. As a result, a VTH < 1.0 V was obtained in all patients with 1450 T electrodes and in 97.7% of patients with 1451 T leads after 6 months follow-up. In both electrodes, stable VTH was reached 2 weeks after implantation, and no transient rise in threshold was observed. No differences were observed between the steroid and the nonsteroid group in respect to VTH, chronaxie-rheobase product, minimum energy consumption, and potential amplitude and slew rate. In conclusion, safe and efficient pacing at low pulse amplitudes were achieved with both leads. The tip design, independently of the steroid additive, prevented any energy-consuming increases in the voltage threshold.

[Coarctation of the descending aorta. A rare form of connatal aortic stenosis]. / Koarktation der Aorta descendens. Eine seltene Form der konnatalen Aortenstenose.

A clinical diagnosis of a coarctation of the aorta was made in a 17-year-old female hypertensive patient. Angiography revealed an atypical stenosis of the descending aorta which was surgically corrected. The causes of aortic stenoses are discussed.