Library

Notes: Objective: Despite the progress that has been reached in emergency medical systems and resuscitation, sudden cardiac death (SCD) continues to be the major cause of the death, and remains a significant public health problem. In this publication we are reporting our Latin American experience in the secondary prevention of SCD, by means of an ongoing registry involving seven Latin American countries and 770 patients. Methods: Every individual within the present registry to date has presented with antecedents of aborted sudden death or cardiac arrest due to ventricular tachycardia or ventricular fibrillation. Patients included have fulfilled the Class I indication for implantable cardioverter defibrillator (ICD) and they were implanted with a Biotronik ICD (all models). The study was not sponsored by Biotronik, nor did they have access to the data. A specific protocol was designed for implantation and follow-up of patients. The database was completely registered through the Internet and a personal password was assigned to each group of investigators. The primary end point was death from all causes. Secondary end points were SCD and death due to congestive heart failure (CHF). Results: The etiology of cardiac disease was found to be predominantly coronary artery disease (CAD) 39.7% (306 patients), followed by Chagas disease (ChD), 26.1% (201 patients), and idiopathic dilated cardiomyopathy (DCM), 17% (131 patients). Any remaining pathologies were included as miscellaneous 13.2% (101 patients). In 31 patients (4%) the etiology was unknown. The age did not differ within the principal pathologies, but was significantly older than the miscellaneous group (62.0 ± 11.3 years vs 48.2 ± 18.9 years, P 〈 0.0001). The follow-up period was 27 ± 25 months (1–113 months) for the whole group. The mortality in functional classes I–II was significantly lower than mortality for functional classes III–IV (relative risk 1.46, CI 95%, P 〈 0.0001). Mean left ventricular ejection fraction (LVEF) for the whole group was 37.7 ± 14.3%. Male LVEF was 36.1 ± 14.1% and female LVEF was 42.2 ± 13.8% P 〈 0.0001. During the follow-up period, 130 deaths were reported (global mortality 16.9 ± 9.7%), out of which 84 (64.6%) were attributed to cardiac causes (10.9 ± 5.1% of the total population). The annual adjusted cardiac mortality was 5.2 ± 1.72% (range 3.5–7.0%). Among cardiac deaths the most common cause was progressive heart failure, 48 patients (57%) including 3 patients with pulmonary embolism. The second main cause of cardiac death was SCD, 36 patients (43%), including 4 patients with electrical storm and 3 patients with electromechanical dissociation after multiple shock therapy treatments. Conclusions: Despite the differences in terms of pathologies between the ICD-LABOR (Latin American bioelectronic ongoing registry) and randomized ICD trials, a parallel evolution in all cause mortality and cardiac mortality was observed. Independent risk factors for mortality included age 〉70 years, male gender, NYHA III/IV, and ejection fraction 〈0.30. The etiology of heart disease (Chagas vs Coronary Disease) was not found to be a risk factor.

Notes: There are many diseases related to ion-channel disorders, so-called “channelopathies.” Hereditary short QT syndrome is a clinical-electrocardiographic entity with autosomal-dominant mode of transmission and it is the most recently described channelopathy. The syndrome may affect infants, children, or young adults with strong positive family background of sudden cardiac death. Short QT syndrome is characterized by short QT and heart-rate-corrected QTc intervals. It is frequently associated with tall-, peaked-, and narrow-based T waves that are reminiscent of the typical “desert tent” T waves of hyperkalemia. There is a high tendency for paroxysmal atrial fibrillation due to the heterogeneous abbreviation of action potential duration and refractoriness of atrial myocytes. The arrhythmia can also be induced by programmed electrical stimulation.The safest treatment suggested is an implantable cardioverter defibrillator, though the possibilities of inappropriate shocks have caused some concern, especially in teenagers.The ability of quinidine to prolong the QT interval has the potential to be an effective therapy for patients with short QT syndrome. This is particularly important in developing countries, where the implantable cardioverter-defibrillator therapy is not always available. Since these patients are at risk of sudden cardiac death from birth, and implantable cardioverter-defibrillator implantation has a lot of limitations in very young children, the utility of quinidine has to be evaluated further. Clinicians need to be aware of this deadly electrocardiographic (ECG) pattern as it portends a high risk of sudden cardiac death in otherwise healthy subjects with structurally normal hearts.

Notes: Background: The purpose of this trial was to evaluate a patient actuated transtelephonic cardiac monitoring system in order to document cardiac arrhythmias and cardiac pacemaker function.Material: Eighty-two patients were prospectively evaluated, 69 with pacemaker (group I) and 13 with symptomatic arrhythmias (group II). Two different recorders were used: a memory loop-recorder (KH) and a wrist-worn recorder (HW). Both of them were implemented using a small, portable, battery-powered transmitter, which monitors a modified V5 in KH and a lead 1 with the HW over regular nondigital pulse telephone lines.Results: In group I, 54 patients used single chamber pacemakers, 2 VDDR, and 13 used dual chamber devices. In group II, all patients included referred palpitations as their symptom. In group I, 248 registers were made using the KH and 50 with the HW. Recordings were made with KH had a 96% accuracy in the diagnosis of the ECG, while HW recordings failed to detect the QRS and the spike in 52% of the cases. Arrhythmia patients (group II) made 65 recordings with KH, all symptomatic: 28 were ventricular ectopic beats (23 isolated, 4 bigeminy, and 1 coupled ventricular ectopic beats); 9 supraventricular ectopic beats (isolated); 18 episodes of sinus tachycardia; and 10 normal sinus rhythm. Artifact was present partially in 6 other recordings, but did not affect the diagnosis. Two patients made no recordings and were excluded from the trial (group I).Conclusions: The loop-recording transtelephonic monitoring system is an excellent tool for the evaluation of patients with symptomatic arrhythmias and pacemaker. The memory KH had an excellent performance, even over regular telephone lines. The accuracy of the HW recordings was low and failed to evaluate the QRS, probably due to the direction of the AQRS vector.

Notes: Andersen's Syndrome is a rare disease, hereditary with autosomal dominant transmission, of the ion channels of the sarcolemmal membranes of the cardiac and skeletal muscles (channelopathy), which affects chromosome 17 of the KCNJ2 gene, responsible for encoding the outward potassium delayed rectifier current KIR2.1, resulting in a loss or suppression of the function of this channel.