RESUMEN
YAG laser with 1318 nm wave was used in the treatment of 23 patients with peripheral lesions of the lungs, 7 of them had multiple lung metastases. Advantage of YAG laser over electric knife was demonstrated. In diagnosis of lung metastases it is necessary to consider not only results of computed tomography but also ones of intraoperative palpation that requires a wide surgical approach for hand manipulation in the pleural cavity. This method permits one to detect more metastases. Lateral thoracotomy with or without rib resection creates optimal conditions for use of YAG laser in surgery of multiple lung metastases.
Asunto(s)
Terapia por Láser/métodos , Neoplasias Pulmonares/secundario , Neoplasias Pulmonares/cirugía , HumanosRESUMEN
We present he case of a young man with nephrotic syndrome, caused by membranous glomerulonephritis, who developed renal vein thrombosis with extension to the inferior vena cava is presented. Renal vein thrombosis was diagnosed by echo Doppler and confirmed by angio-CT scan. At the hospitalization the patient presented a severe left flank pain, edema of the lower limbs and painful left testicular tumefaction. The treatment consisted of: 1) systemic anticoagulation with sodic heparin, 2) placement of temporary vena cava filter through the right jugular vein, 3) direct thrombolysis into endocaval thrombus with early lysis of thrombus, and 4) renal thrombolysis with selective simultaneous renal artery and renal vein infusion of urokinase. Angiography performed after 24 hours of loco-regional thrombolysis showed complete lysis of renal thrombus; clinically there was a regression of left flank pain. We conclude that, face to renal vein thrombosis, thrombolytic treatment with simultaneous renal artery and renal vein perfusion is mandatory. Furthermore it is very important, in presence of caval extension of renal thrombus, to place a temporary vena cava filter before starting thrombolysis, considering the high risk of pulmonary embolism related to this pathology.
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Activadores Plasminogénicos/administración & dosificación , Arteria Renal , Venas Renales , Terapia Trombolítica/métodos , Activador de Plasminógeno de Tipo Uroquinasa/administración & dosificación , Trombosis de la Vena/tratamiento farmacológico , Adulto , Humanos , Infusiones Intraarteriales , Infusiones Intravenosas , MasculinoRESUMEN
PURPOSE: To report a case demonstrating successful endovascular treatment of a right common carotid artery pseudoaneurysm using a commercially prepared balloon-expandable covered stent. METHODS AND RESULTS: A 50-year-old man was evaluated for syncopal episodes. He had a history of severe trauma sustained in a motor vehicle accident 3 years before symptom onset. Doppler ultrasound scanning detected a pseudoaneurysm at the origin of the right common carotid artery. The defect measured 25 mm x 20 mm with a 22-mm-long neck on angiography and computed tomography; there was no evidence of carotid stenosis or associated vascular pathology. Via a percutaneous femoral access, 2 Jostent peripheral stent-grafts were placed at the level of the aneurysm, safely achieving complete repair of the arterial wall defect. The patient was asymptomatic at his 12-month evaluation. Color flow duplex scans showed continued exclusion of the pseudoaneurysm. CONCLUSIONS: Wide-necked aneurysms in the extracranial carotid arteries may be treated with stent-grafts, which can achieve complete and permanent reconstruction of the arterial wall by excluding the aneurysm.
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Aneurisma Falso/cirugía , Implantación de Prótesis Vascular/instrumentación , Enfermedades de las Arterias Carótidas/cirugía , Arteria Carótida Común , Materiales Biocompatibles Revestidos , Stents , Aneurisma Falso/diagnóstico por imagen , Angiografía , Enfermedades de las Arterias Carótidas/diagnóstico por imagen , Cateterismo , Humanos , Masculino , Persona de Mediana Edad , Politetrafluoroetileno , Diseño de Prótesis , Tomografía Computarizada por Rayos X , Ultrasonografía DopplerRESUMEN
Post-myocardial infarction risk stratification, especially arrhythmic risk stratification, is an issue that has still not been wholly addressed in modern clinical cardiology. In the past 10 years, arrhythmic risk stratification has been approached mainly by evaluating frequency and complexity of premature ventricular contractions, detected on Holter monitoring, often in association with determination of percent ejection fraction. This methodology has been proven to be limited and fallacious according to the Cardiac Arrhythmia Suppression Trial I and II (CAST I,II) results, in which suppression of premature ventricular contractions or premature ventricular beats throughout by antiarrhythmic drugs resulted in an increase in both cardiac and arrhythmic mortality. Only amiodarone as an antiarrhythmic drug, as proven in the recent European Myocardial Infarct Amiodarone Trial (EMIAT) and Canadian Amiodarone Myocardial Infarction Trial (CAMIAT), was effective in reducing arrhythmic mortality without affecting cardiac mortality, in patients selected mainly because of a reduced ejection fraction, with and without premature ventricular contractions. Conversely, it is well known that beta-blockers are effective in preventing sudden death in post-acute myocardial infarction (AMI) patients, thus reducing cardiac and arrhythmic mortality. Conversely, in other institutions, risk stratification in post-AMI patients has been performed by electrophysiologic study obtained, without any previous noninvasive arrhythmic risk stratification, in all post-AMI patients. In recent years, many other noninvasive electrocardiology parameters, such as late potentials (signal-averaged electrocardiography), heart rate variability, baroreflex sensitivity, and, more recently, T-wave alternance, have been shown to be useful, but they are associated with a low specificity in the noninvasive identification of patients at high risk for arrhythmic mortality. Conversely, in the Multicenter Automatic Defibrillation Implantation Trial (MADIT), electrophysiology confirmed that inducibility of ventricular tachycardia shows high specificity and a high predictive value for arrhythmic events. Nevertheless, the MADIT study population is not comparable to a cohort of consecutive patients who have recently had a myocardial infarction. In this setting, the highest risk of arrhythmic events can be observed in patients with depressed percent ejection fraction (< 35%) and in the first 6 months after AMI. Today, the most convincing approach seems to be the one combining both noninvasive risk stratification parameters (e.g., premature ventricular beats > 10/h or reduced heart rate variability < 70 ms or a positive signal-averaged electrocardiogram) followed by a further arrhythmic risk stratification, obtained through electrophysiologic study. Several published and ongoing trials that utilize various arrhythmic risk stratification techniques as part of their protocol are reviewed.
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Arritmias Cardíacas/mortalidad , Infarto del Miocardio/complicaciones , Amiodarona/uso terapéutico , Antiarrítmicos/uso terapéutico , Arritmias Cardíacas/diagnóstico , Arritmias Cardíacas/etiología , Muerte Súbita Cardíaca/etiología , Muerte Súbita Cardíaca/prevención & control , Electrofisiología , Humanos , Infarto del Miocardio/tratamiento farmacológico , Infarto del Miocardio/mortalidad , Factores de RiesgoRESUMEN
The prospective evaluation and follow-up of 39 consecutive subjects with VT/VF, 6 of whom, with cardiac arrest (CA), are reported. Patients were enrolled in a specific staged-care approach protocol, which included coronary arteriography (CAR) and ventriculography (VC), in order to exclude the need of cardiac surgery, including coronary artery bypass graft (CABG), with and without left ventricular aneurysmectomy (LVA). The protocol included inducibility of VT/VF, which was verified by programmed electrical stimulation (PES) in control conditions and after antiarrhythmic therapy (ADT), to assess persistent inducibility and mainly to verify the hemodynamic sequelae of VT. VT that showed poor hemodynamic tolerance was treated with ICD, while well-tolerated VT was treated by ADT or ablation when indicated. Furthermore, PES was obtained after surgical procedures. As a first step, the patients were assigned to receive amiodarone (AMIO) (200-400 mg/daily) in the presence of EF% < 30% or contraindication to sotalol, (Group A), or sotalol (SOT) (80-140 mg/daily) in the presence of EF > or = 31%. (Group C). Conversely, in case of recurrences, patients were assigned to receive AMIO (200-300 mg/daily) plus metoprolol (MET) (20-100 mg/daily), (Group B) or, in case of intolerance to beta-blockers, to AMIO plus mexiletine (MEX) (200 mg/daily) (Group D). The four groups were similar for the type of VA, with recurrent ventricular tachycardia (RVT) being the most frequent one. The most frequent underlying cardiac disease of VA in this study was post-AMI CAD, with a rate of over 60% in all four groups. Single- and two-vessel lesions were found at CAR in various patients in all four groups, in 5/13 (38%) in Group A, in 8/14 (57%) in Group B, in 5/7 (71%) in Group C, and in 3/5 (60%) in Group D. Cardiac surgery was performed in a similar and limited number of patients in all four groups, in 4/13 (30%) in Group A, in 4/14 (35%) in Group B, in 2/7 (28%) in Group C, and in 2/5 (40%) in Group D. In 8/39 (20.5%) of the patients who underwent CABG, there was no operative or late mortality; 4/39 (10.2%) received CABG and LVA, and two died. For the amiodarone plus metoprolol and sotalol patients only, PES showed a lower residual inducibility, in comparison to the amiodarone and amiodarone + mexiletine groups. In the entire group, 7 out of 26 (27%) were still inducibile at PES while in 19/26 (64%) of the patients, an apparently effective treatment could be found, documenting the relative usefulness of PES. Recurrence rate was the highest in the amiodarone + mexiletine group and in patients with previous CA. Our data show the potential utility and limitations of ADT, even using the most effective antiarrhythmic drugs and association of drugs, mainly because of the high recurrence rate of VT observed in the present study, even in non-inducible patients [14/39 (36%)]. In conclusion, in a prospective and staged-care approach protocol of management of VT/VF patients, only a few patients with VT/VF benefited from cardiac surgery. PES could still play a role in the evaluation of the most effective ADT. Amiodarone + metoprolol seems to be the most effective ADT in these patients. Nevertheless, a high recurrence rate was observed in this patient population, even with an aggressive protocol, in the short follow-up period of 12 +/- 8 months, confirming recent data on the superiority of ICD to ADT, in patients with frequent recurrences or hemodynamically poorly-tolerated VT. In these patients, ICD therapy should definitively be preferred to ADT.
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Procedimientos Quirúrgicos Cardíacos , Angiografía Coronaria , Enfermedad Coronaria/diagnóstico , Taquicardia Ventricular/diagnóstico , Fibrilación Ventricular/diagnóstico , Adulto , Anciano , Anciano de 80 o más Años , Amiodarona/uso terapéutico , Antiarrítmicos/uso terapéutico , Cateterismo Cardíaco , Estudios de Cohortes , Puente de Arteria Coronaria , Enfermedad Coronaria/cirugía , Enfermedad Coronaria/terapia , Desfibriladores Implantables , Estimulación Eléctrica , Estudios de Seguimiento , Aneurisma Cardíaco/cirugía , Trasplante de Corazón-Pulmón , Humanos , Metoprolol/uso terapéutico , Persona de Mediana Edad , Estudios Prospectivos , Sotalol/uso terapéutico , Taquicardia Ventricular/terapia , Factores de Tiempo , Fibrilación Ventricular/terapiaRESUMEN
Clinical electrocardiographic evaluation and complete non-invasive assessment including nuclear magnetic resonance (NMR) are reported for 7 subjects with cardiac arrest (CA), 6 due to ventricular fibrillation (VF) and 1 to ventricular tachycardia (VT). Two more subjects, one with and one without a family history of non-resuscitated sudden death (NRSD), were included. All 9 subjects showed the typical pattern of the Brugada's syndrome (BS), characterized by incomplete right bundle branch block, ST T elevation in V1 V3. We globally evaluated 64 subjects belonging to the 9 families examined, 5 of whom were identified in Bologna, 3 in Florence and one in Parma. BS is characterized in the experience described in the present paper by a family distribution of the ECG pattern in different members. Furthermore, a family distribution of NRSD, even at a young age, was observed. Electrocardiographic features were consistent with variable degrees and aspects of the intraventricular conduction delay (ICD) and of the ST T elevation pattern. NMR has been performed so far in 23 out of 64 members examined by echo, and was normal in 17/23, with only 6 showing pathological aspects such as mild dilatation of the right ventricle, reduced thickness of the right free wall, isolated dilatation of the right ventricular infundibulum and other minor pathological aspects. Preliminary genetic screening (GS), performed on 20 members of three families, was negative for the typical genetic patterns of right ventricular dysplasia (ARVD). In six families, GS is still ongoing. Genetic screening of sodium channel pathology is in progress in the same families. In conclusion, BS has been documented in the present paper as a hereditary syndrome, both for clinical and ECG aspects, associated with CA due to VF, which required an AICD implantation, at least in symptomatic subjects. There may exist a CONGENITAL form of BS due to pathology of sodium channels, without a demonstrable structural heart disease and an ACQUIRED form of BS secondary to an initial ARVD. From the clinical point of view, a complete evaluation, including serial ECG, pharmacological testing and programmed electrical stimulation of other subjects in the families, may be important in preventing sudden death, mainly in symptomatic subjects who always require an implantable cardioverter defibrillator.
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Bloqueo de Rama/diagnóstico , Bloqueo de Rama/genética , Muerte Súbita Cardíaca , Electrocardiografía , Femenino , Humanos , Masculino , Linaje , SíndromeAsunto(s)
Angioplastia de Balón , Arteria Axilar/efectos de la radiación , Arteria Ilíaca/efectos de la radiación , Traumatismos por Radiación/terapia , Constricción Patológica , Femenino , Humanos , Arteria Ilíaca/diagnóstico por imagen , Persona de Mediana Edad , Traumatismos por Radiación/diagnóstico por imagen , Traumatismos por Radiación/etiología , Radioterapia/efectos adversos , Stents , Ultrasonografía IntervencionalRESUMEN
Some 1257 patients who had undergone revascularization procedures for unilateral iliac occlusions were reviewed retrospectively. A total of 824 patients were operated upon using conventional operations, 165 patients had femorofemoral bypass and 268 were treated using endovascular surgery techniques. Revascularization was performed through an extraperitoneal approach by means of iliac thromboendarterectomy (560) or iliac femoral bypass (264) if there was a total occlusion of either the common or external iliac artery (group 1). A femorofemoral crossover bypass was inserted when the operative risk was considered to be high (group 2). Endovascular procedures (percutaneous transluminal angioplasty 234, laser percutaneous transluminal angioplasty 11, stenting 22, atherectomy one) were used in recent years to treat stenoses or occlusions of 3 cm or less (group 3). The indications for operation were severe claudication in 79.7% in group 1 and 92.6% in group 3, whereas in group 2 66.7% of patients presented with symptoms of more advanced ischaemia. The immediate patency rate was 97.0% after extraperitoneal reconstructive surgery, 96.9% in the femorofemoral group and 92.1% in patients having an endovascular procedure. The operative mortality rate was 0.7, 4.2, and 0.3% for groups 1-3, respectively. The 5-year patency rate, analysed by the life-table method, was 77.9% in group 1, 75.3% in group 2 and 73.7% in group 3 (P = n.s., log rank test). The different revascularization techniques were chosen on the basis of the type of disease present and the patient's general condition. All procedures appeared to be effective when correctly selected.
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Angioplastia de Balón , Arteriopatías Oclusivas/cirugía , Endarterectomía , Arteria Femoral/cirugía , Arteria Ilíaca/cirugía , Stents , Adulto , Anciano , Anciano de 80 o más Años , Arteriopatías Oclusivas/terapia , Constricción Patológica/cirugía , Femenino , Humanos , Claudicación Intermitente/cirugía , Isquemia/cirugía , Tablas de Vida , Masculino , Persona de Mediana Edad , Reoperación , Estudios Retrospectivos , Tasa de Supervivencia , Trombectomía , Grado de Desobstrucción VascularRESUMEN
A 61-year-old female presented with symptomatic recurrent left internal carotid stenosis. A method of intraoperative balloon dilatation under protective clamping of the common carotid artery is described.
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Angioplastia de Balón/métodos , Estenosis Carotídea/terapia , Cuidados Intraoperatorios/métodos , Arteria Carótida Interna/diagnóstico por imagen , Estenosis Carotídea/diagnóstico por imagen , Constricción , Endarterectomía Carotidea , Femenino , Humanos , Persona de Mediana Edad , Radiografía , RecurrenciaRESUMEN
The role of coronary artery disease (CAD) in hypertrophic cardiomyopathy (HC) has not been thoroughly clarified. To assess the clinical and prognostic significance of these 2 coexistent diseases, 96 patients with HC (62 men, mean age 45 years) who underwent coronary arteriography and 2-dimensional echocardiography were studied. Significant stenosis (greater than 70%) of 1 or more coronary arteries was detected in 11 patients, all aged greater than 45 years. This group, compared with the other group without significant CAD (n = 85), was characterized by an older age (59 +/- 7 vs 42 +/- 15 years; p less than 0.05), a greater prevalence of previous myocardial infarction (24 vs 0%; p less than 0.001), complex ventricular arrhythmias (100 vs 50%; p less than 0.05), non-obstructive forms (82 vs 46%; p less than 0.05), dilated (45 vs 7%; p less than 0.02) and hypocontractile left ventricle (36 vs 6%; p less than 0.01) and higher mortality (36 vs 8%; p less than 0.05) during a mean follow-up of 3.6 years. It is concluded that CAD associated with HC is a complex clinical syndrome, difficult to diagnose clinically, that can reliably be recognized by coronary angiography. CAD seems to play an important role in modifying the pathophysiology, the natural history and the prognosis of HC.
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Cardiomiopatía Hipertrófica/complicaciones , Enfermedad Coronaria/complicaciones , Adolescente , Adulto , Anciano , Angiografía Coronaria , Enfermedad Coronaria/diagnóstico , Enfermedad Coronaria/fisiopatología , Ecocardiografía , Electrocardiografía , Femenino , Hemodinámica , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Volumen SistólicoRESUMEN
We examined 44 patients (pts) with hypertrophic cardiomyopathy to evaluate the prognostic value of signal-averaged electrocardiography and its possible correlations with clinical and instrumental data. All pts (31 male, 13 female, mean age 47 +/- 15) underwent clinical examination, standard electrocardiography, M-mode and two-dimensional echocardiography, 24-72 hour dynamic electrocardiography and signal-averaged electrocardiography. The mean follow-up was 14 +/- 4 months. Signal-averaged electrocardiography was performed using a 40-250 Hz bidirectional filter. An abnormal signal-averaged electrocardiography with late potentials (filtered QRS duration greater than or equal to 120 msec and root mean square voltage in terminal 40 msec less than or equal to 20 microvolts) was detected in 5 pts (group A, 11%) while 39 pts (group B, 89%) had a normal signal-averaged electrocardiography. Ventricular tachycardia runs at dynamic ECG were present in 2 pts in group A (40%), and in 8 in group B (21%, p = NS). No statistical differences were found between the two groups for any clinical or instrumental data. During our study, one group A patient died suddenly. In detecting subjects with ventricular tachycardia runs, signal-averaged electrocardiography sensitivity was 20%, and specificity was 91%. High specificity suggests that signal-averaged electrocardiography might be used to detect pts at a lower risk for ventricular tachycardia. Further investigations are required to evaluate the predictive value of signal-averaged electrocardiography for sudden death in hypertrophic cardiomyopathy.
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Cardiomiopatía Hipertrófica/fisiopatología , Electrocardiografía , Adolescente , Adulto , Anciano , Cardiomiopatía Hipertrófica/diagnóstico , Electrocardiografía/métodos , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Estudios ProspectivosRESUMEN
The effectiveness of verapamil in preventing ventricular fibrillation caused by coronary occlusion or reperfusion has been well demonstrated in animal studies, but these experimental data have not yet been confirmed in man. In this study we evaluated the prevalence of ventricular arrhythmias (fibrillation, sustained tachycardia and frequent extrasystoles) in patients hospitalized for myocardial infarction and treated with or without verapamil. The records of patients admitted to our Coronary Intensive Care unit during a 5-year period were analyzed retrospectively. Strict selection criteria enabled us to divide our patients into two homogeneous groups. The control group (group A) consisted of 106 patients who received only continuous infusions of heparin. The treated group (group B) comprised 89 patients who received exclusively verapamil by intravenous injections followed by continuous infusions. The prevalence of ventricular arrhythmia of all types was significantly lower in group B (22 p. 100) than in group A patients (71 p. 100; p less than 0.001). Episodes of ventricular fibrillation, in particular, were considerably less frequent in group B patients (1 p. 100) than in group A patients (13 p. 100; p less than 0.001). It would appear from these results that verapamil is highly effective in preventing death due to cardiac arrhythmia in the acute phase of myocardial infarction.
Asunto(s)
Infarto del Miocardio/complicaciones , Fibrilación Ventricular/prevención & control , Verapamilo/uso terapéutico , Complejos Cardíacos Prematuros/etiología , Complejos Cardíacos Prematuros/prevención & control , Femenino , Humanos , Infusiones Intravenosas , Inyecciones Intravenosas , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Taquicardia/etiología , Taquicardia/prevención & control , Fibrilación Ventricular/etiología , Verapamilo/administración & dosificaciónRESUMEN
The Authors reports on a case of isolated infarction of the right ventricle, with electrocardiographic pattern of non-transmural anterior myocardial infarction and haemodynamic profile suggestive of important diastolic disfunction. Clinical, angiographic and haemodynamic data are discussed along with review of the literature.
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Electrocardiografía , Hemodinámica , Infarto del Miocardio/fisiopatología , Ventrículos Cardíacos , Humanos , Masculino , Persona de Mediana Edad , Infarto del Miocardio/diagnóstico por imagen , Infarto del Miocardio/patología , RadiografíaRESUMEN
Recent studies have demonstrated that body surface maps (BSM) can be employed as non-invasive diagnostic tool for recognizing cardiac states at risk for repetitive ventricular arrhythmias in patients (pts) with old infarction. Our study reports preliminary results of a new method of statistical analysis of ST-T isoarea maps for identifying patients with post-infarction sustained ventricular tachycardia. 38 pts with previous myocardial infarction have been studied, 25 without and 13 with sustained ventricular tachycardia (VT). The two groups of pts did not differ significantly for age, site of infarction and ejection fraction. BSM have been recorded by means of an automated 35-channels instrument from 140 thoracic leads. For each lead ST-T deflection area has been calculated in microV.sec and taken as input variables for stepwise discriminant analysis which allowed identification of the integral values significantly discriminant (for F less than 0.15) between the two groups. Canonical analysis has been applied to identified values to obtain, by canonical coefficients, linear combination of the values for the highest correlation with the two groups of pts. To test the power of the method, the two groups of pts have been divided randomly in a learning set (17 pts without and 9 pts with VT) and a test set (8 pts without and 4 pts with VT).(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Electrocardiografía/métodos , Infarto del Miocardio/complicaciones , Taquicardia/diagnóstico , Adulto , Anciano , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Taquicardia/etiología , Taquicardia/fisiopatologíaRESUMEN
We provided a topographic and quantitative description of body surface maps (BSM) during the entire QRST interval in seven uncomplicated LBBBs and 31 LBBBs complicated by: myocardial infarction (MI, seven cases), left ventricular hypertrophy (LVH, eight cases), myocardial ischemia (IS, seven cases), MI + LVH (six cases) and LVH + IS (three cases). In all patients we observed abnormal map configurations attributable to the LBBB. We were unable to identify consistent effects of the complicating heart condition(s) on the general pattern of chest potentials. Conversely, the surface voltages were generally decreased by MI and IS and increased by LVH. By considering the 38 patients as a preliminary learning set we applied a stepwise discriminant analysis to 77 voltage-related variables derived from BSM to produce a model for discriminating between LBBBs with and without MI. We properly allocated more than 90% of the patients. We also attempted to classify the patients into four groups: pure LBBB, LBBB + MI, LBBB + LVH and LBBB + IS, with a percentage of correct classification of about 80%. The two classifying procedures were applied to ten new LBBB patients with results similar to those obtained in the 38 of the study group.
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Bloqueo de Rama/diagnóstico , Cardiomegalia/complicaciones , Enfermedad Coronaria/complicaciones , Electrocardiografía , Infarto del Miocardio/complicaciones , Adulto , Anciano , Anciano de 80 o más Años , Animales , Bloqueo de Rama/complicaciones , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
In 58 human subjects monophasic action potentials (MAPs) were recorded with suction electrodes in several areas of the right ventricle (RV). Individual differences between the longest and the shortest RV MAP durations indicate that: normally (40 subjects) ventricular repolarization is almost synchronous; QT prolongation due either to bradycardia or to amiodarone treatment (eight cases) may be the result of a uniform lengthening of ventricular repolarization, when ventricular arrhythmias are not present; in long QT syndromes (LQTSs) of differing etiology (10 cases), in which severe ventricular arrhythmias are present, marked individual differences in RV MAP duration are present and correspond with pathological asynchrony of ventricular repolarization. Also observed in the LQTSs are morphological alterations (humps) in the terminal phase of the longest MAPs. Humps, interpreted as pathological delayed repolarization phenomena, may lead to focal re-excitation which seems to play a key role in the genesis of the arrhythmias complicating LQTSs.
Asunto(s)
Arritmias Cardíacas/fisiopatología , Electrocardiografía , Sistema de Conducción Cardíaco/fisiopatología , Síndrome de QT Prolongado/fisiopatología , Adolescente , Adulto , Anciano , Amiodarona/efectos adversos , Bradicardia/fisiopatología , Complejos Cardíacos Prematuros/fisiopatología , Estimulación Cardíaca Artificial , Niño , Femenino , Bloqueo Cardíaco/fisiopatología , Ventrículos Cardíacos/fisiopatología , Humanos , Síndrome de QT Prolongado/inducido químicamente , Masculino , Persona de Mediana Edad , Taquicardia/fisiopatologíaRESUMEN
Monophasic action potentials (MAPs) were recorded with intracardiac suction electrodes in several areas of the right ventricle in 10 patients with long QT syndromes (with "torsades de pointe') of different etiology. In all cases two characteristic electrophysiological features were observed: (1) a marked difference in MAP duration in the different areas of the right ventricle (asynchronous repolarization); (2) an alteration in the shape of the longest MAPs consisting in humps which occurred on the repolarization phase of MAP. Humps may be interpreted as delayed repolarization phenomena probably due to a decrease in potassium conductance of some ventricular cells. These may lead to focal re-excitation as a result of partial membrane depolarization. Focal re-excitation seems to play a key role in the genesis of severe arrhythmias occurring in the above mentioned syndromes.
Asunto(s)
Arritmias Cardíacas/fisiopatología , Electrocardiografía , Potenciales de Acción , Adulto , Anciano , Complejos Cardíacos Prematuros/fisiopatología , Estimulación Cardíaca Artificial , Niño , Femenino , Ventrículos Cardíacos/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Síncope/fisiopatología , Síndrome , Taquicardia/fisiopatologíaRESUMEN
Programmed stimulation can now be safely performed for the evaluation of therapy for recurrent ventricular tachyarrhythmia. The initiation of ventricular tachycardia appears closely related to its actual spontaneous clinical occurrence. Serial electrophysiologic studies can be performed and are effective in prospectively evaluating the response to antiarrhythmic drugs. The efficacy of therapy based on the results of programmed stimulation appears to be good. On the other hand, Amiodarone can be effective in the chronic treatment as well as in patients with ineffective acute drug test.