[Subcutaneous implantable Holter. A new instrument for the diagnosis of syncope of undetermined origin]. / El Holter implantable subcutáneo. Un nuevo instrumento para el diagnóstico del síncope de origen no determinado.

We present a recurrent syncope case with no clear origin or not stabilized after complete diagnostic exploration including echocardiogram, Holter, carotid Doppler, electrophysiologic study, computerized tomography, etc. Due to its recurrence and sudden appearance which was presumed to be of cardiac origin we implanted a long recording subcutaneous Holter system, the first unit used in Spain. This device, which has several advantages compared to external recorders previous in use, facilitated the patient's diagnosis (arrhythmic syncope of cardiac origin due to a paroxysmal atrioventricular block) one month after implantation. We describe the system, which includes a recorder and an external activator, its handling and diagnostic capabilities as well as the implantation procedures.

[The current status of permanent cardiac pacing in Spain. A report of the National Pacemaker Data Bank]. / Estado actual de la estimulación cardíaca definitiva en España. Informe del Banco Nacional de Datos de Marcapasos.

We report the activity concerning permanent cardiac pacing in Spain during year 1995, based on data submitted to the National Pacemaker Registry corresponding to the European Pacemaker Card. We describe population, etiology and electrocardiographic alterations that determined the need for stimulation and the global distribution of stimulation modes (AAI 1.7%; DDD 20.2%; VDD 11.3% and VVI 66.8%). We emphasize, among other aspects, stimulation in A-V block cases, in sick-sinus syndrome and tendencies compared to 1994's data and limited data corresponding to 1996.

[Immediate hemodynamic response to atrioventricular+ stimulation in severe hypertrophic obstructive myocardiopathy]. / Respuesta hemodinámica inmediata a la estimulación bicameral en la miocardiopatía hipertrófica obstructiva severa.

INTRODUCTION AND OBJECTIVES: Atrial synchronized ventricular pacing has shown to be an alternative to surgery in the therapeutic management of obstructive hypertrophic cardiomyopathy. Our purpose is the analysis of the hemodynamic mechanisms associated with the reduction of left ventricular outflow tract gradient and the changes in left ventricular diastolic function induced by dual-chamber pacing. PATIENTS AND METHODS: We studied twenty patients (age range 40-78 years; mean 63 +/- 10), who were evaluated while receiving their current medication with cardiac catheterization and angiography, at baseline and under dual-chamber pacing. RESULTS: The atrioventricular delay was 127 +/- 26 ms. The subaortic gradient was reduced from 96 +/- 38 to 36 +/- 28 mmHg (p < 0.001), the ejection period index was shortened from 523 +/- 26 to 491 +/- 30 ms (p < 0.001) and the left ventricular end-diastolic pressure fell from 22 +/- 6 to 13 +/- 5 mmHg (p < 0.001). There was no remarkable change in cardiac output. The median wedge pressure decreased from 17 +/- 5 to 12 +/- 2.5 mmHg (p < 0.01), the pulmonary systolic pressure from 39 +/- 15 to 30 +/- 10 mmHg (p < 0.01), the pulmonary diastolic pressure from 19 +/- 5 to 13 +/- 4 mmHg (p < 0.01) and the right ventricular end-diastolic pressure from 7 +/- 3 to 5 +/- 3 mmHg (p < 0.05). The left ventricular ejection fraction was reduced from 79 +/- 6 to 72 +/- 6 per cent (p < 0.001). The initial ejection fraction diminished from 49 +/- 13 to 34 +/- 13 per cent (p < 0.01), the early diastolic filling increased from 39 +/- 11 to 52 +/- 10 per cent (p < 0.001) and the atrial contribution was reduced from 36 +/- 10 to 24 +/- 10 per cent (p < 0,001). The degree of mitral regurgitation changed from 1.4 +/- 1.2 to 0.7 +/- 0.9 (p < 0.01). CONCLUSIONS: There is an obstruction in the left ventricular outflow tract in patients with obstructive hypertrophic cardiomyopathy that is relieved with dual-chamber pacing. The reduction in the intraventricular pressure seems to improve the ventricular relaxation and the diastolic function. The decrease in the degree of mitral regurgitation and the improvement in diastolic function diminish pulmonary capillary and right circuit pressures.

[Biosensors and rate-responsive cardiac pacing]. / Biosensores y estimulación cardíaca autorregulable en frecuencia.

Patients with atrioventricular block and ventricular pacemakers at a fixed rate have their exercise ability limited. This situation has been solved through dual chamber pacing in those patients keeping an adequate sinus node function. For the remaining, showing chronotropic failure or atrial fibrillation, the ability to increase their pacing rate is only possible when signals other than atrial activity, and reflecting metabolic needs, are used as a guide. These signals detected by a sensor, act through an algorithm modifying the pacing rate and are the cornerstone of rate-responsive pacing. Indications for these stimulation modes are analyzed as so are characteristics of different sensors used for this aim (pH, respiratory rate, QT interval, body activity, minute respiratory volume, central venous pressure, preejection period + stroke volume, right ventricular dp/dt, evoked QRS response and venous oxygen saturation).

[Clinical experience and long-term results of antitachycardia pacemakers in patients with supraventricular tachycardia]. / Experiencia clínica y resultados a largo plazo de los marcapasos antitaquicardia en pacientes con taquicardia supraventricular.

Patients with episodes of recurrent paroxysmal supraventricular tachycardia, refracted to different pharmacologic therapies, can be treated with automatic antitachycardia pacemakers. Long term results of 8 patients (6 females and 2 males), mean age 49.8 +/- 12.7 years, are presented. There were implanted an antitachycardia pacemaker 262-12 Intertach, with an electrode in right atrium. Electrophysiologic study showed a node reentry mechanism in 6 cases due to AV node functional dissociation; one case of accessory concealed pathway and other case with a double accessory pathway was undetected in the electrophysiologic study and it was the unique case in which the pacemaker was explanted due to their inefficiency. Every tachycardia were orthodromic with narrow QRS wave and mean cycle was 361 +/- 23 msec (range 310-400 msec). One case had two types of tachycardia, one with narrow QRS wave and other wide QRS wave tachycardia and different length of cycle what reduced to detect a previously double pathway. A reoperation was necessary in one case due to an electrode displacement and, finally, another one needed a reprogramming auricular sensitivity. Mean time follow-up was more than 2 years. Seven patients have sinusal rhythm without drugs and they have 6 months follow-up with a better quality of life, less hospital incomes and medical cares.

[Noninvasive cardiac electric stimulation in emergencies]. / Estimulación eléctrica cardíaca no invasiva en urgencias.

The results of electrical transcutaneous cardiac stimulation (ETCCS) were evaluated in 38 emergency situations seen at the Emergency Service of the Hospital 12 de Octubre (Madrid) during one year. ETCCS is a noninvasive stimulation procedure through electrodes placed on the chest surface (negative left sub-mamillary and positive right infraclavicular--AA--or left subscapular--AP2--). The stimulation impulse has a duration of 0.01-0.04 seconds depending on the type of device used, with intensities which can achieve 200 mA and stimulation frequencies up to 180/min. The high electrical (97.4%) and mechanical (75.7%) effectiveness of ETCCS in our series, its acceptable tolerance (80.1% of the conscious patients) and its easy management have led us to support the use of electrocardiographic monitor-defibrillator-ETCCS units for the complete early electrical support of emergencies associated with disorders of the cardiac rhythm. This support may be given in emergency areas with minimal training requirements.