Brugada type 1 electrocardiographic pattern induced by severe hyponatremia.

Brugada syndrome is characterized electrocardiographically by ST segment elevation in the right precordial leads, followed by a negative T wave unrelated to ischemia, electrolyte disturbance or drug effects and prone to rapid polymorphic ventricular tachycardia capable of degenerating into ventricular fibrillation. The ECG pattern may be dynamic and is often concealed. Sodium channel blockers, drugs, electrolyte imbalances, fever and several other clinical circumstances are recognized inducers of a Brugada type 1 ECG in susceptible patients. We describe a case of a Brugada type 1 ECG pattern induced by severe hyponatremia.

[Sudden death due to commotio cordis associated to non compacted myocardium]. / Muerte súbita por conmoción cardiaca (Commotio cordis) asociada a miocardio no compactado.

Non compact of the left ventricular myocardium is a rare congenital cardiomyopathy characterized by the presence of multiple and prominent deep trabeculations in the ventricular wall, that define recesses communicated with the main ventricular chamber. This is a condition with low incidence and prevalence, diagnosed through imaging techniques such as Doppler echocardiogram (DE), multi-slice computed tomography (MSCT) or magnetic resonance imaging (MRI). Clinically, it may be asymptomatic or manifested by cardiac arrhythmias, heart failure or thromboembolism. This is a report on a 33 year old asymptomatic man who suffered a blow on his chest (commotio cordis) during a sports competition that produced a cardiac arrest. The electrocardiogram showed ventricular flutter that required electrical defibrillation. A DE obtained initially, did not show any significant abnormality, but another DE, a MSCT and a RMN obtained after discharge, certified isolated non-compacted myocardium, ruling out coronary artery disease. He received beta blocker and antiplatelet therapy and the placement of an automatic cardioverter defibrillator was considered. The pathophysiology of the association of these two infrequent and potentially lethal conditions is discussed.

[Hypothyroidism, dilated cardiomyopathy and nephrotic syndrome during pregnancy]. / Hipotiroidismo, miocardiopatía dilatada y síndrome nefrótico durante el embarazo.

Hypothyroidism during pregnancy is infrequent, but its presence is associated with maternal and fetal complications. We present the case of a young pregnant woman with no previous history of cardiovascular disease, who consulted for orthopnea, chest pain and edema in both legs. Laboratory tests demonstrated a hypothyroid condition and a nephrotic syndrome with renal failure. The echo-Doppler exam showed a four chamber dilatation with systolic dysfunction. Treatment with intravenous levothyroxine improved her medical condition. We analyze the effects of thyroid hormone on the heart and vascular system and discuss the pathophysiologic mechanisms of heart failure during pregnancy.

[Hormone replacement therapy and cardiovascular prevention. Where are we now?]. / Terapia hormonal de reemplazo en prevención cardiovascular. Dónde estamos parados?

During their fertile period women suffer significantly less atherosclerotic cardiovascular disease (particularly myocardial infarction) than men. This benefit progressively disappears after menopause, to equalize after the sixth decade of life. Experimental studies in animal and human models demonstrated the existence of physiological mechanisms suggesting that estrogens could be responsible for this cardiovascular protection, and retrospective analysis of clinical studies showed that post menopausal women who had used hormonal replacement therapy (HRT) suffered less cardiovascular events. These observations stimulated the execution of several prospective, randomized clinical trials (some of them with a large number of patients and prolonged follow-up) in post menopausal women, with the aim of proving the hypothesis that HRT could prevent major cardiovascular events. Such hypothesis could not be demonstrated in any of those studies because HRT was not beneficial, and in several cases it was even deleterious in some aspects. Criticism has arisen over some of the methodological aspects of those prospective trials, basically regarding the age of the included patients and the timing of the beginning of HRT. There are also biological reasons that can explain the contradiction. A new hypothesis, also based on experimental and clinical observations, suggests the possibility that beginning HRT in younger women and earlier after menopause could yield different results.

Continuous improvement of arterial compliance beyond blood pressure decrease after 5 years of antihypertensive treatment.

Pulse wave velocity is a reliable marker of arterial compliance. Stiffness of large and elastic arteries leads to a faster propagation of pulse wave. The aim of this study was to evaluate changes in arterial distensibility using antihypertensive drugs. This treatment focused on the inhibition of the renin-angiotensin-aldosterone system and the changes produced in blood pressure. Measurements were taken at baseline and throughout 60 months in 66 previously untreated hypertensive patients (22 men and 44 women, aged 54 +/- 9.5 years, range 38-73 years at baseline). All patients received either angiotensin-converting enzyme inhibitors or, in case of adverse effects, angiotensin receptor blockers. To control blood pressure, diuretics, calcium channel blocking agents, or beta blockers were added when appropriate. Statistical analysis was performed by means of ANOVA with alpha = 0.05. Systolic and diastolic blood pressure decreased during the first year without significant changes thereafter. There were no significant changes in pulse pressure. Pulse wave velocity showed a continuous and significant decrease throughout the follow-up period, but its reduction since the third year was more evident than the decrease in systolic and diastolic blood pressure (p < 0.0001 for both). This observation could be related to changes in arterial remodeling probably due to angiotensin-converting enzyme inhibition or renin angiotensin system blockade. Further investigations are needed to establish this relationship.

Tolvaptan administration does not affect steady state amiodarone concentrations in patients with cardiac arrhythmias.

BACKGROUND: Tolvaptan, a nonpeptide selective vasopressin receptor (V2) antagonist, is in development for the treatment of congestive heart failure and hyponatremia. Tolvaptan is primarily metabolized via CYP3A4. This study was conducted to determine the extent of the pharmacokinetic interaction between tolvaptan and steady state amiodarone, an antiarrhythmic drug commonly prescribed for patients with congestive heart failure and a known inhibitor of other drugs metabolized by CYP3A4. METHODS: This was a multicenter, open-label, 1-arm, 3-period, sequential treatment study conducted in 11 men (10) and women aged 49 to 80 years. They were primarily Caucasian (20) subjects, with a history of cardiac arrhythmias who were otherwise healthy. Subjects were to have been on oral amiodarone maintenance therapy of 200 mg/day for at least 10 months. All subjects took 200 mg amiodarone once daily on each study day; on days 3 and 4, they were also coadministered 30 and 90 mg of tolvaptan, respectively. The plasma concentrations of amiodarone and its metabolite desethylamiodarone were determined for 24 hours postdose on days 2, 3, and 4, tolvaptan concentrations were determined for 24 hours postdose on days 3 and 4. RESULTS: As determined by the ratio of the geometric means and 90% confidence intervals (0.5 to 2.0) for the maximal plasma concentration and the area under the curve during the dosing interval for both amiodarone and desethylamiodarone, tolvaptan coadministration had no effect on either amiodarone and desethylamiodarone disposition, as all the geometric mean ratios (amiodarone + tolvaptan [30 or 90 mg] vs amiodarone alone) were approximately 1. CONCLUSION: Tolvaptan coadministration does not alter steady-state amiodarone or desethylamiodarone concentrations. Tolvaptan concentrations did not appear to be different from historical controls. The most frequently reported adverse event was polyuria (15 of 21 subjects for amiodarone + 30 mg tolvaptan); an expected outcome due to the known potent aquaretic action of tolvaptan. The combination of amiodarone and tolvaptan was well tolerated.

Factores de riesgo cardiovascular no convencionales / Unconventional cardiovascular risk factor

Desde hace varias décadas se conocen los clásicos factores de riesgo cardiovascular (género, edad, hipertensión arterial, dislipidemias, tabaquismo, obesidad, sedentarismo). También existen factores de riesgo "no convencionales", es decir situaciones no descriptas ni contenidas en la mayoría de los puntajes de riesgo tradicionales, pero de las cuales existen evidencias científicas. En esta revisión se analizan algunos de ellos, tales como factores socioeconómicos, horarios prolongados de trabajo, factores ambientales, aislamiento social, cantidad y calidad del sueño. También hay factores de "protección" cardiovascular como la dieta mediterránea. La literatura cuenta con un número muy elevado de publicaciones que abarcan estos factores. En la presente descripción se incluyeron algunas que fuesen representativas, con buen diseño experimental y que hayan realizado análisis multivariado de los resultados para controlar potenciales confundidores que invaliden las conclusiones. Finalmente, se discuten los mecanismos fisiopatológicos involucrados en la generación de los eventos cardiovasculares finales. (AU)

The classical cardiovascular risk factors have been known for several decades (gender, age, arterial hypertension, dyslipidemia, smoking, obesity, sedentary lifestyle). There also exist "non conventional" risk factors, that are those not described or not included in the majority of the traditional cardiovascular risk scores, but for whom scientific evidence is available. In this review some of them are analyzed, such as socio economic factors, prolonged work schedules, environmental factors, social isolation, sleep quantity and quality. There are also some "preventive" cardiovascular factors as the Mediterranean diet. There exist considerable amount of publications in the literature analyzing these issues. In the present paper some of them are discussed. They have been selected as they were representative of the corresponding aspect, well designed and with multivariate statistical analysis of the results, in order to control potential confounders that could invalidate the conclusions. Finally, the pathophysiological mechanisms involved are discussed. (AU)

[First degree atrio-ventricular block in acute thyrotoxicosis]. / Bloqueo aurículo-ventricular de primer grado en tirotoxicosis aguda.

Thyrotoxicosis may present with a variety of cardiovascular symptoms. Sinus tachycardia is the most frequently encountered electrocardiographic abnormality and conduction disturbances are extremely uncommon. We present a case of first degree atrio-ventricular block in a patient with newly diagnosed hyperthyroidism and discuss the underlying pathophysiological mechanisms and the clinical implications from the internist's standpoint.

[Pulse wave velocity and urinary albumin excretion in hypertensive patients treated with perindopril]. / Velocidad de la onda de pulso y la excreción urinaria de albúmina en pacientes hipertensos tratados con perindopril.

Systolic and diastolic blood pressures and urinary albumin excretion (UAE) have been recognized as predictors for cardiovascular risk. Furthermore, arterial compliance (AC) disorders assessed by increased aortic pulse wave velocity (PWV) are closely related to changes in blood pressure and strongly correlated with cardiovascular mortality and presence or extent of atherosclerosis. Our purpose in the present study was to determine a relationship between AC using PWV and UAE in a group of non-smoking patients with essential hypertension, and the level of interaction of ACE inhibition on these two variables. A total of 70 non-smoking never treated hypertensive patients (33 men and 37 women), aged 50 +/- 7 years (range 35-69), have been enrolled in this study. All of them underwent PWV by a computerized device (Complior) and UAE determination by radial immunodiffusion method, on baseline and after six months of treatment with perindopril (4.6 +/- 1.4 mg/day). We have found a significant decrease of systolic blood pressure (160.2 +/- 10.6 vs. 131.9 +/- 7.1 mmHg, p < 0.01), diastolic blood pressure (100.6 +/- 5 vs. 81.6 +/- 4.8 mmHg, p < 0.01), PWV (13.4 +/- 1 vs. 9.1 +/- 0.9 m/sec, p < 0.01), and UAE (42.2 +/- 19.3 vs. 11.1 +/- 3.6 mg/day, p < 0.01) at the end of the sixth month when they were compared to baseline values. Furthermore, renal function was also improved by the treatment at the end of the study as illustrated by creatinine clearance (87.5 + 22.5 vs. 102.1 + 23.5 ml/min, p < 0.01). Moreover, a high positive correlation between UAE and PWV at the beginning of the study (r = 0.81; p < 0.01) and after six months of treatment (r = 0.66; p < 0.01) was observed. In addition, PWV vs. UAE, differences between sixth month and baseline have shown a high correlation (r = 0.67; p < 0.01) and using a multiple regression test we found that PWV (t ratio 5.76; p < 0.001) was the most important and significant independent variable that correlates with UAE. These results suggest the existence of a real link between UAE and AC in non-smoking patients with arterial hypertension, and that ACE inhibition can similarly modify these two parameters.

Can the cold pressor test predict future cardiovascular events in patients without demonstrated ischemic heart disease by SPECT?

OBJECTIVE: To assess whether a cold pressor test (CPT) could help identify patients at a high risk of cardiovascular events in a population without known coronary artery disease (CAD) with a normal myocardial perfusion scintigraphy (MPS). METHODS: Our population consisted of 870 patients with a mean age of 59.3years with several CAD risk factors, having been referred for an MPS. The CPT was performed between the third day and fifth day after the MPS. RESULTS: The CPT was positive in 38.2% of the patients. After a mean 40-month follow-up, the patients were contacted to check for cardiac death, non-fatal myocardial infarction, and myocardial revascularization procedures. The event-free survival rates were 98.1% and 90.4% after a negative or positive CPT, respectively (p=0.0001). The positive CPT group exhibited a fourfold increased risk of CV events. All CV events in the negative CPT group occurred after a 30-month follow-up. The risk of CV events was 4.5 times higher in diabetic patients. CONCLUSION: A positive CPT in patients with a negative MPS could help identify a subgroup of patients at a higher risk of developing symptomatic CAD. PRACTICE IMPLICATIONS: Our results suggest that after a normal post-exercise MPS, patients should undergo a CPT.

Histomorphometry of umbilical cord blood vessels in preeclampsia.

The authors hypothesized that preeclampsia may change the phenotype of umbilical cord vessels. Segments of umbilical cords were obtained from 29 pregnant women (20 healthy and 9 with preeclampsia), which were histomorphometrically assessed. Birth weight was 2928 ± 613 g for the control group vs 1749 ± 656 g for the preeclampsia group (P<.0001). A significantly shorter gestational period was noted in the preeclampsia group: 35 weeks vs 39 weeks in the healthy group. Measurements of the outer layer area (116.4 ± 55 µm(2) vs 56.5±25 µm(2) ; P=.0038), the inner layer area (63.1 ± 16 µm(2) vs 28.6±8 µm(2) ; P<.0001), the lumen area (8.4 ± 1 µm(2) vs 3.4±2 µm(2) ; P=.0003), and the wall/lumen ratio (20.3 ± 9 vs 3.1 ± 0.6; P<.0001) of arteries were significantly larger in the preeclampsia umbilical cords. Concerning veins, the wall/lumen ratio was higher in the preeclampsia group. In this study, the umbilical cord in preeclampsia showed significant changes in the structure of umbilical arteries, with increases in wall areas and wall/lumen ratios.

Assessment of endothelial function by means of flow-mediated changes using pulse wave velocity.

Endothelial dysfunction is a leading cause of early development of cardiovascular diseases. Endothelial function can be assessed using ultrasound methods to watch the arterial flow-mediated dilation. It is also possible to find changes in pulse wave velocity (PWV) after induced ischemia related to the vessel diameter changes. Pre- and post-induced ischemia carotid-radial PWV was recorded in 226 hypertensive patients (150 women [63.5+/-12.4 years old] and 76 men [63.2+/-11.8 years old] and 55 healthy patients (38 women [63.1+/-12.6 years old] and 17 men [54.8+/-12.8 years old]). The authors considered normal endothelial function a PWV reduction of 5% from baseline. To assess nondependent endothelial dilation the authors performed carotid-radial PWV after sublingual administration of 5 mg of isosorbide dinitrate in a group of patients with abnormal flow-mediated dilation. A significant PWV reduction of 9.8% in normal patients and only 1.2% among hypertensive patients (P<.0005) was found. After sublingual isosorbide dinitrate intake the authors observed a greater fall in PWV (14%) than that observed in healthy people after induced ischemia. Carotid-radial PWV after induced ischemia decreased significantly in normal participants. No significant changes were observed in hypertensive patients. These results may offer a reliable tool to assess endothelial function in medium-size arteries.

Encuesta sobre la calidad de vida profesional de los cardiólogos en la Argentina / Survey on Professional Quality of Life of Argentine Cardiologists

Introducción: Pese a que los estudios sobre calidad de vida profesional han incluido distintas clases de profesionales de la salud, no existen publicaciones al respecto de los médicos cardiólogos en Latinoamérica y en particular en la Argentina. Objetivo: Estudiar mediante una encuesta la calidad de vida profesional de los cardiólogos en la Argentina. Material y métodos: Se trató de un estudio observacional y transversal con un cuestionario validado de acuerdo con distintas características métricas. La encuesta se realizó desde abril a junio de 2007 y tuvo carácter anónimo. El cuestionario autoadministrado estuvo constituido por 14 preguntas separadas en tres dominios que midieron: la percepción de la situación laboral del cardiólogo, la realización personal y la expectativa de futuro. Resultados: De 972 cardiólogos de todo el país contactados por e-mail, completaron la encuesta 717 (74%). Los indicadores de calidad de vida profesional mostraron que el 53,5% (383) de los cardiólogos cree que su situación laboral actual es regular o mala y el 61,0% (437) cree que esto no mejorará en el futuro. El 77,4% (555) está preocupado por su estabilidad laboral y el 82,9% (595) cree que podría ser demandado por mala praxis. En relación con la expectativa de futuro, el 17,3% (124) de los cardiólogos no volvería a elegir la especialidad, el 24,3% (174) no volvería a estudiar medicina y el 37,7% (270) no estaría satisfecho si un hijo decidiese estudiar medicina. Conclusiones: Esta primera encuesta sobre calidad de vida profesional de los cardiólogos en la Argentina describe la percepción de estos especialistas sobre su situación laboral, realización personal y profesional y expectativa de futuro. Los datos que surgen de la encuesta revelan un claro panorama de insatisfacción de los cardiólogos argentinos en el actual sistema organizativo de la salud.

Background: Despite studies on professional quality of life have included different types of health care professionals, there are no publications addressing the professional quality of life of cardiologists in Latin America, particularly in Argentina. Objective: The aim of this study is to use a survey to evaluate the professional quality of life of Argentine cardiologists. Methods: This observational, cross-sectional study consisted of a questionnaire validated according to different metric characteristics. The survey was conducted from April to June 2007 and was anonymous. The self-administered questionnaire consisted of 14 questions, separated in three domains measuring the cardiologist perception of the work situation, self-fulfillment and expectation about the future. Results: Among 972 cardiologists from all the country contacted by e-mail, 717 (74%) completed the survey. The indicators of professional quality of life demonstrated that 53.5% (383) of cardiologists believe that their current work situation is fair or bad and 61.0% (437) believe that this situation will not improve in the future; 77.4% (555) are worried about their job security and 82.9% (595) believe they could be sued for malpractice. Regarding the expectation about the future domain, 17.3% (124) of cardiologists would not choose the specialty again, 24.3% (174) would not study medicine again and 37.7% (270) would not be satisfied if one of his/her children decided to study medicine. Conclusions: This first survey on professional quality of life of Argentine cardiologists describes how these specialists perceive their work situation, self-fulfillment, professional achievement and expectation about the future. This information reveals a clear state of dissatisfaction among Argentine cardiologists within the current organization of the health care system.