Obstructive sleep apnea is associated with increased QT corrected interval dispersion: the effects of continuous positive airway pressure / Apneia obstrutiva do sono está associada a maior dispersão do intervalo QT corrigido: efeitos da pressão positiva contínua nas vias aéreas

Abstract Introduction: Severe obstructive sleep apnea is associated with increased QT corrected interval dispersion and continuous positive airway pressure is thought to improve this arrhythmogenic marker. Objective: The aim of the study was to determine the decrease of ratio of cardiovascular risk in patients with obstructive sleep apnea. Methods: The study included 65 patients with severe obstructive sleep apnea who had an apnea-hypopnea index score of >30. Each patient underwent 12-channel electrocardiogram monitoring and polysomnography. Patients with an apnea-hypopnea index score of <5 were used as the control group. The control group also underwent electrocardiogram monitoring and polysomnography testing. The QT corrected interval dispersion levels of both groups were calculated. Three months after continuous positive airway pressure treatment, electrocardiogram recordings were obtained from the 65 patients with severe obstructive sleep apnea again, and their QT corrected interval dispersion values were calculated. Results: There were 44 male and 21 female patients with severe obstructive sleep apnea syndrome. The age, gender, body mass index, initial saturation, minimum saturation, average saturation, and desaturation index were determined in both groups. The QT corrected intervals of the obstructive sleep apnea patients (62.48 ± 16.29 ms) were significantly higher (p = 0.001) than those of the control group (29.72 ± 6.30 ms). There were statistically significant differences between the QT corrected values before and after the continuous positive airway pressure treatment, with pretreatment QT corrected intervals of 62.48 ± 16.29 ms and 3-month post-treatment values of 41.42 ± 16.96 ms (p = 0.001). There was a positive and significant correlation between QT corrected interval dispersion periods and the apnea-hypopnea index and hypopnea index in obstructive sleep apnea patients (p = 0.001; r = 0.71; p = 0.001; r = 0.679, respectively). Conclusion: Continuous positive airway pressure treatment reduced the QT corrected interval dispersion in patients with severe obstructive sleep apnea. In addition, shortening the QT corrected interval dispersion periods in patients with severe obstructive sleep apnea may reduce their risk of arrhythmias and cardiovascular disease.

Resumo Introdução: A apneia obstrutiva do sono grave está associada a uma maior dispersão do intervalo QT corrigido e acredita-se que a pressão positiva contínua nas vias aéreas melhore esse marcador arritmogênico. Objetivo: Determinar a diminuição da razão de risco cardiovascular em pacientes com apneia obstrutiva do sono. Método: O estudo incluiu 65 pacientes com apneia obstrutiva do sono grave que apresentavam índice de apneia-hipopneia > 30. Cada paciente foi submetido à monitoração por eletrocardiograma de 12 derivações e polissonografia. Os pacientes com escore de índice de apneia-hipopneia < 5 foram utilizados como o grupo de controle. O grupo de controle também foi submetido à monitoração por eletrocardiograma e teste de polissonografia. Os níveis de dispersão do intervalo QT corrigido dos dois grupos foram calculados. Três meses após o tratamento com pressão positiva contínua nas vias aéreas, os registros de eletrocardiograma foram novamente obtidos dos 65 pacientes com apneia obstrutiva do sono grave e seus valores de dispersão do intervalo QT corrigido foram calculados. Resultados: Havia 44 pacientes do sexo masculino e 21 do feminino com síndrome de apneia obstrutiva do sono grave. Idade, sexo, índice de massa corporal, saturação inicial, saturação mínima, saturação média e índice de dessaturação foram determinados em ambos os grupos. Os intervalos QT corrigido dos pacientes com apneia obstrutiva do sono (62,48 ± 16,29 ms) foram significativamente maiores (p = 0,001) do que os do grupo controle (29,72 ± 6,30 ms). Houve diferenças estatisticamente significativas entre os valores de QT corrigido antes e após o tratamento com pressão positiva contínua nas vias aéreas, com intervalos QT corrigido pré-tratamento de 62,48 ± 16,29 ms e três meses pós-tratamento, de 41,42 ± 16,96 ms (p = 0,001). Houve uma correlação positiva e significativa entre os períodos de dispersão do intervalo QT corrigido e o índice de apneia-hipopneia e índice de hipopneia em pacientes com apneia obstrutiva do sono (p = 0,001; r = 0,71; p = 0,001; r = 0,679, respectivamente). Conclusão: O tratamento com pressão positiva contínua nas vias aéreas reduziu a dispersão do intervalo QT corrigido em pacientes com apneia obstrutiva do sono grave. Além disso, o encurtamento de dispersão do intervalo QT corrigido em pacientes com apneia obstrutiva do sono grave pode reduzir o risco de arritmias e doenças cardiovasculares.

Síndrome de QT largo y taquicardia ventricular en torsade de pointes secundarios a hipopituitarismo: una asociación a tener en cuenta: caso clínico / Long QT syndrome and polymorphic ventricular tachycardia due to hypopituitarism: report of one case

Symptoms of hypopituitarism are usually chronic and nonspecific, but rarely the disease can have acute and life threatening manifestations. We report a 53 years old female with a pituitary adenoma that was admitted to our hospital because of syncope. The electrocardiogram showed sinus bradycardia with a prolonged QT interval. Frequent runs of non-sustained polymorphic ventricular tachycardia were noted on telemetry. The patient had a history of severe acute headaches in the previous days and laboratory tests revealed severe secondary hypothyroidism, adrenal insufficiency and a decrease in pituitary hormones. A magnetic resonance imaging of the head showed changes in the size and contrast enhancement of the adenoma. A diagnosis of hypopituitarism secondary to pituitary apoplexy was made and treatment with hydrocortisone and, subsequently, levothyroxine was started. Hormonal disorders such as hypothyroidism, adrenal insufficiency or hypopituitarism should be considered as unusual causes for reversible cardiomyopathy, long QT syndrome and ventricular arrhythmias.

Síndrome do QT longo adquirido em paciente portadora de doença de Fahr / Acquired long QT syndrome in a patient with Fahr's disease

A síndrome do QT longo é uma doença caracterizada por um atraso na repolarização ventricular, que se manifesta como síncope cardíaca até morte súbita. Alguns distúrbios hidroeletrolíticos podem corresponder à forma adquirida da síndrome, como a hipocalcemia. A hipocalcemia pode ocorrer em função do hipoparatireoidismo, que, em um quadro crônico, pode determinar calcificação em núcleos da base no sistema nervoso central, caracterizando a doença de Fahr. Paciente ISC, sexo feminino, 71 anos, referiu episódio de perda súbita da consciência associado a movimentos tônico-clônicos e relaxamento esfincteriano.Os achados do exame físico foram hipotensão arterial (80x60mmHg) e bradipsiquismo. Foi realizado eletrocardiograma, que mostrou alargamento do segmento QT, corrigido em 0,57'' pela fórmula de Bazett. Na história pregressa, referiu tiroidectomia parcial à direita há 20 anos, hipotireoidismo e hipertensão arterial. Fazia uso de quatro anti-hipertensivos e de um tireoestimulante. A análise da tomografia de crânio mostrou densos componentes calcificados nas regiões dos gânglios da base. A ultrassonografia de tireoide mostrou lobotomização à direita. O diagnóstico de hipoparatireoidismo foi suspeitado pelos sintomas de fadiga, sonolência, e sinais de Chvostek e Trousseau positivos, e confirmado por exames que demonstraram hipocalcemia significativa, hiperfosfatemia e níveis reduzidos de hormônio paratireóideo. Por se tratar de um quadro insidioso, o diagnóstico de hipoparatireoidismo é pouco elucidado apenas pela clínica. Neste caso, o alargamento do QT foi imprescindível para esclarecer e tratar sua etiologia. Além disso, a doença de Fahr, apesar de rara, deve ser considerada diante de um paciente com hipoparatireoidismo e história clínica compatível

Long QT syndrome is a disease characterized by a delay in ventricular repolarization that is manifested as cardiac syncope or even as sudden death. Some water and electrolyte disturbances can reflect the acquired form of the syndrome, such as hypocalcemia. Hypocalcemia can arise because of hypoparathyroidism, which in a chronic setting can determine basal ganglia calcification in the central nervous system, featuring Fahr's disease. ISC, female, 71, reported an episode of sudden loss of consciousness associated with tonic-clonic movements, and sphincter relaxation. Physical examination findings were hypotension (80x60mm Hg) and bradypsychism. The electrocardiogram (ECG) showed QT interval prolongation, corrected for 0.57'' by Bazett's formula. In her previous history she reported right partial thyroidectomy 20 years ago, hypothyroidism and high blood pressure. She made use of four anti-hypertensive drugs and one thyroid stimulating hormone. CT scan analysis showed dense calcified componentes in the regions of basal ganglia. Thyroid ultrasound showed right lobotomization. The diagnosis of hypoparathyroidism was suspected due to symptoms of fatigue, sleepiness, and positive signs of Chvostek and Trousseau, and confirmed by tests that showed significant hypocalcemia, hyperphosphatemia and low levels of parathyroid hormone (PTH) Because of its insidious picture, the diagnosis of hypoparathyroidism is only slightly elucidated by the clinical exam. In this case, QT prolongation was essential to clarify and treat its etiology. Furthermore, Fahr's disease, although rare, should be considered in a patient with hypoparathyroidism and consistent clinical history.

Alteraciones electrocardiográficas en anorexia nervosa: revisión crítica de la literatura / Electrocardiographic abnormalities in anorexia nervosa: a critical review of the literature

Introducción: La anorexia nervosa (AN) es un trastorno de la conducta alimentaria y, entre sus causas de mortalidad, las arritmias cardiacas y la muerte súbita son frecuentes, por lo que es indispensable la monitorización electrocardiográfica. Se han descrito muchos hallazgos con resultados contradictorios, por lo que es necesaria una revisión crítica de la literatura científica. Metodología: Revisión de los estudios relevantes sobre cambios electrocardiográficos en AN, consultados en PubMed desde 1974 hasta febrero de 2014, utilizando los términos MeSH: Eating disorders, nervosa anorexia, sinusal bradycardia, QT prolongation, QT dispersion, electrocardiography, EKG, electrocardiogram. Resultados y discusión: Las dos alteraciones más comunes reportadas incluyen la bradicardia sinusal y los cambios en la repolarización evidenciados en prolongación del QT e incremento de su dispersión. Los trastornos electrolíticos parecen ser la causa de estas alteraciones en algunos pacientes, pero otras razones se discuten en detalle, como la desviación del eje del QRS a la derecha, la alteración en variabilidad de la frecuencia cardiaca, R en derivación V6 de bajo voltaje, disminución de la amplitud del QRS y onda T y alargamiento del QRS. La mayoría de los autores hablan de reversibilidad de los cambios después del tratamiento. Conclusiones: Estos resultados siguen apoyando la necesidad de valorar a los pacientes con AN con electrocardiogramas inicial y de seguimiento, para el diagnóstico temprano y tratamiento de alteraciones cardiovasculares relacionadas con alta morbimortalidad. También apoyan la necesidad del uso racional de psicofármacos para no aumentar el riesgo de arritmias cardiacas y muerte súbita.

Background: Anorexia nervosa is an eating disorder in which cardiac arrhythmias and sudden death are frequent causes of mortality, which makes electrocardiographic monitoring indispensable in these patients. There are many suggestive findings but results are contradictory, making a critical review of the scientific literature is necessary. Methods: The most relevant studies on electrocardiographic (EKG) changes in patients with AN, found in PubMed from 1974 to February 2014, were reviewed using the MeSH terms: eating disorders, nervosa anorexia, sinus bradycardia, QT prolongation, QT dispersion, electrocardio graphy, EKG, and electrocardiogram. Findings and discussion: The two most common EKG findings reported in the literature are sinus bradycardia and changes in depolarization, as shown by prolongation and increased dispersion of the QT interval. Electrolyte disturbances seem to be the cause of these disturbances in some patients, but other reasons are also discussed in detail, such as QRS right axis deviation, disturbances of heart rate variability, low R wave voltage in V6, amplitude decrease of the QRS and T wave, and QRS prolongation. The majority of authors report that these changes are reversible after treatment of AN. Conclusions: These findings support the need for initial and follow-up EKGs in patients with AN and for early diagnosis and treatment of cardiovascular disturbances that are associated with morbidity and mortality. They also support the need for the rational use of psychop harmacology, and that does not increase the risk of arrhythmias and sudden death in these patients.

Síndrome QT largo congénito / Congenital long-QT syndrome

Se presenta un caso de síndrome de QT largo congénito que debutó con muerte súbita durante el período del puerperio.

QT dispersion and early arrhythmic risk in acute myocardial infarction.

BACKGROUND: This study sought to find out QT dispersion in healthy individuals and patients of acute myocardial infarction and to find correlation, if any, between QT dispersion and the incidence of ventricular arrhythmias in acute myocardial infarction. METHODS AND RESULTS: QT dispersion was calculated from a 12-lead electrocardiogram in 100 patients of acute myocardial infarction admitted in intensive coronary care unit and 100 age- and sex-matched healthy individuals. In patients of acute myocardial infarction, QT dispersion was calculated on admission, 24 hours after admission and at the time of discharge from intensive coronary care unit. Average QT dispersion in acute myocardial infarction was found to be significantly higher on admission (76.4 +/- 18.3 ms), 24 hours after admission (62.88 +/- 17.52 ms) and at the time of discharge from intensive coronary care unit (51.79 +/- 16.79 ms) than in healthy individuals (29.76 +/- 6.06 ms; p<0.05). QT dispersion was found to be significantly increased in patients of acute myocardial infarction with ventricular arrhythmias (82.06 +/- 16.86 ms) than in those without (66.75 +/- 16.28 ms; p<0.01). Patients of acute myocardial infarction with ventricular tachycardia or ventricular fibrillation had significantly increased QT dispersion (96.25 +/- 15.97 ms) than those who had only ventricular premature beats (80 +/- 15.04 ms; p<0.01). QT dispersion was found to be significantly greater in patients with anterior wall acute myocardial infarction (79.80 +/- 18.19 ms) than in those with inferior wall acute myocardial infarction (71.9 +/- 17.48 ms; p<0.05). At the time of discharge from intensive coronary care unit no statistically significant difference was found in QT dispersion in those who received thrombolysis (51.58 +/- 16.05 ms) and those who did not (48.18 +/- 14.68 ms; p>0.05). QT dispersion was found to be significantly higher in those who died (88.66 +/- 15.97 ms) than in those who survived (74.23 +/- 17.91 ms; p<0.05). QT dispersion was significantly higher in ventricular arrhythmic deaths (97.14 +/- 17.04 ms) than those who had non-arrhythmiac deaths (81.25 +/- 11.25 ms; p<0.05). CONCLUSIONS: Interlead QT variation and its measure as QT dispersion challenges our current approach to the electrocardiographic assessment of arrhythmic risk. QT dispersion may provide a potentially simple, cheap, non-invasive method of measuring underlying dispersion of ventricular excitability.

Torsade de pointes in a case of pheochromocytoma--an unusual presentation of an uncommon disease.

We report the case of a middle aged lady with dilated cardiomyopathy, presenting with recurrent syncope due to torsade de pointes. Further evaluation revealed that she had a pheochromocytoma which caused the arrhythmia.

Mulheres alcoolistas: alterações eletrocardiográficas e distúrbios metabólicos e eletrolíticos associados / Female alcoholics: electrocardiographic changes and associated metabolic and electrolytic disorders

OBJECTIVE: To identify the electrocardiographic changes and their associations with metabolic and electrolytic changes in female alcoholics. METHODS: The study comprised 44 female alcoholics with no apparent physical disorder. They underwent the following examinations: conventional electrocardiography; serologic tests for syphilis, Chagas' disease, and hepatitis B and C viruses; urinary pregnancy testing; hematimetric analysis; biochemical measurements of albumin, fibrinogen, fasting and postprandial glycemias, lipids, hepatic enzymes, and markers for tissue necrosis and inflammation. RESULTS: Some type of electrocardiographic change was identified in 33 (75 percent) patients. In 17 (38.6 percent) patients, more than one of the following changes were present: prolonged QTc interval in 24 (54.5 percent), change in ventricular repolarization in 11(25 percent), left ventricular hypertrophy in 6 (13.6 percent), sinus bradycardia in 4 (9.1 percent), sinus tachycardia in 3 (6.8 percent), and conduction disorder in 3 (6.8 percent). The patients had elevated mean serum levels of creatine phosphokinase, aspartate aminotransferases, and gamma glutamyl transferase, as well as hypocalcemia and low levels of total cholesterol and LDL-cholesterol. The patients with altered electrocardiograms had a more elevated age, a lower alcohol consumption, hypopotassemia, and significantly elevated levels of triglycerides, postprandial glucose, sodium and gamma glutamyl transferase than those with normal electrocardiograms. The opposite occurred with fasting glycemia, magnesium, and alanine aminotransferase. CONCLUSION: The electrocardiographic changes found were prolonged QTc interval, change in ventricular repolarization, and left ventricular hypertrophy. Patients with normal and abnormal electrocardiograms had different metabolic and electrolytic changes

Utilización de cisaprida y su relación con arritmia cardiaca. Estado actual en la literatura médica / use cisapride and its relationship to cardiac arrhythmia. State of the art in medical literature

El monohidrato de cisaprida es el procinético más utilizado para el tratamiento de desórdenes sintomáticos de la motilidad intestinal; ha sido utilizado tanto en niños como en adultos; se encuentra disponible en presentación como suspensión pediátrica en un gran número de países incluyendo México desde 1984. Se calcula que ha sido prescrito en más de 140 millones de pacientes. Los aspectos con relación a su farmacocinética y farmacodinámica han sido reevaluados desde los reportes de su utilización y su asociación con alargamiento del segmento electrocardiográfico QT, arritmia ventricular y muerte. Hasta diciembre de 1999 se habían reportado 80 muertes asociadas con su utilización. Janssen decidió limitar su producción en los Estados Unidos, dejándolo en disponibilidad sólo para protocolos de investigación. Con estos antecedentes se han realizado análisis retrospectivos, estudios prospectivos en poblaciones de distintas edades, con búsqueda y hallazgo de factores de riesgo hasta en 85 por ciento de los pacientes que han presentado arritmias ventriculares. La finalidad de este documento es revisar los aspectos farmacológicos de la cisaprida, comentar los factores identificables asociados con arritmia ventricular, y realizar una revisión de los aspectos seguridad y eficacia de la cisaprida, así como establecer factores de riesgo para presentar arritmia ventricular.

La cisaprida no altera el intervalo Q-T prolongado en pacientes con cirrosis hepática / Cisapride does not modify prolonged Q-T interval in patients with liver cirrhosis

Background: Abnormal small bowel motility, observed in liver cirrhosis, can be reversed with cisapride. Since both cisapride and liver disease are associated with prolonged QT interval, the possibility of adverse cardiovascular effects might be expected with cisapride treatment in these patients. Aim: To evaluate QT interval and other electrocardiographic changes during long term treatment with cisapride in cirrhotic patients. Patients and methods: Forty seven cirrhotic patients were studied. Electrocardiogram was recorded and the QT interval corrected according to Bazzett's formula was determined (normal value <0.44 s). Seventeen patients were treated with cisapride, 10 mg tid for seven months and electrocardiographic controls were performed at the end of the treatment. Results: The mean corrected QT interval was 0.46 ñ 0.03 s (range 0.4-0.53). 34 patients (64 percent) had QTc prolongation (0.47 ñ 0,02 s). Statistically significant higher values of QTc were observed in patients at Child Pugh stage B and C compared to stage A. No statistically significant difference according to the etiology of liver disease, were observed. No changes in mean QTc duration were observed during cisapride treatment. Conclusions: In spite that a prolonged QTc was a frequent finding in our serie of selected patients, no cardiovascular adverse effects were observed with long term cisapride treatment

Torsade de Pointes: una causa de síncope en disfunción del nodo sinusal / Torsade de Pointes: a cause of syncope in sinus node dysfunction

Torsade de Pointes (TdP) es una taquicardia ventricular atípica, que ocurre en casos de prolongación de intervalo QT y puede ser una anormalidad congénita o adquirida. TdP es una complicación reconocida de las bradirritmias, específicamente en el bloqueo atrioventricular. Sin embargo, la disfunción del nodo sinusal es una causa rara de síncope asociado a TdP. Estudios experimentales han sugerido que el intervalo QT largo adquirirdo y TdP pueden deberse a pospotenciales tempranos, bradicardia o pausa-dependiente, que llevan a automatismo por actividad disparada. Este reporte describe el caso de una paciente con intervalo QT largo inducido por bradicardia sinusal, ritmo nodal AV intermitente y síncope repetitivo secundario a TdP, tratado exitosamente con estimulación cardiaca temporal y a largo plazo

El ecocardiograma en la evaluacion del compromiso cardíaco en las espondiloartropatias seronegativas / Echocardiography in the evaluation of cardiac involvement in seronegative spondylo-arthropathies

Se estudió compromiso cardíaco en pacientes con espondiloartropatías seronegativas utilizando la ecodopplercardiografía. De los 35 pacientes, 20 eran portadores de espondilitis anquilosantes, 10 de síndrome de Reiter y 5 presentaban artritis psoriásica. Se estudiaron 21 hombres y 14 mujeres de entre 17 y 68 años. La mayoría (65,71 por ceinto) no presentaba sintomatología cardíaca y 12 (34, 29 por ciento) eran oligosintomáticos. El sintoma predominante era palpitaciones. Todos fueron sometidos a un estudo ecodoppler y electrocardiográfico. El ecocardiograma mostró alteraciones en 19 pacientes (54, 29 por ciento), de ellos, el 28,50 por ciento era asintomáticos y el 25,71 por ciento presentaba síntomas cardiovasculares. El examen bidimensional fue el que detectó mayor número de alteraciones (17/19-84,47 por ciento), en tanto que el Doppler pulsado detectó 10 de los 19 (52,63 por ceinto) y unidimensional (9/19-47,36 por ciento). La válvula aórtica estaba comprometida en 10 pacientes (28,58 por ciento) de los que 7 tenían engrosamiento y 3 calcificación; la válvula mitral mostraba alteraciones en 11 enfermos (57,89 por ciento), engrosamientos en 9, calcificación en 1 y prolapso en 2. No se observaron alteraciones en las válvulas tricúspide y pulmonar. El Doppler pulsado detectó 4 insuficiencias aórticas y 3 mitrales. El compromiso valvular aórtico estaba presente en 8 (40 por ciento) de los pacientes con espondilitis anquilosante. El examen electrocardiográfico presentó una bradicardia sinusal, un bloqueo aurículo-ventricular de 1er grado, un bloqueo de rama derecha y 19 casos con ATc prolongado. El ecocardiograma demostró ser un método no invasivo de gran utilidad para revelar alteraciones cardíacas en los pacientes con espondiloartropatías seropnegativas