Clinical characteristics of patients with drug-induced QT interval prolongation and torsade de pointes: identification of risk factors.

The present study aimed to investigate the causative medications and underlying risk factors that predispose to drug-induced QT interval prolongation. Twenty-one patients with drug-induced long QT (90% females, mean age 64.3 +/- 14.1 years) were included in the study. Transthoracic echocardiography as well as continuous or ambulatory 48-h electrocardiographic monitoring was carried out in all patients during their hospitalization. The mean corrected QT (QTc) interval was 542 +/- 56.8 ms. Known cardiac agents (mainly class III antiarrhythmics) were implicated in 13/21 (62%), antipsychotics in 8/21 (38%), and antibiotics in 5/21 patients (24%). Potential drug-interactions through inhibition of cytochrome P450 isoenzymes were considered responsible in 5/21 cases (24%). The underlying cardiovascular diseases included hypertension (57%) with left ventricular hypertrophy (29%), paroxysmal atrial tachyarrhytmias (48%), heart failure (14%), valvular heart disease (10%), and coronary artery disease (5%). Torsade de pointes (TdP) was recorded in 6/21 of patients, and cardiac arrest necessitating resuscitation occurred in five of them. A significant correlation was observed between administration of cardiac agents and TdP events (P < 0.05). TdP and cardiac arrest events were both associated with a QTc interval >510 ms (P < 0.05). Advanced age (>60 years), female gender, hypertension and paroxysmal atrial tachyarrhytmias were the most common identifiable pre-existing factors for drug-induced long QT in our patient cohort. Marked QTc interval prolongation should be considered of prognostic significance for TdP and cardiac arrest events.

Large left atrial myxoma presented as fever of unknown origin: a challenging diagnosis and a review of the literature.

Myxoma is the most common type of primary tumors of the heart in adults. The majority of patients with myxomas may experience symptoms due to central or peripheral embolism or intracardiac obstruction, while in some cases, they may be completely asymptomatic. Rarely, patients develop unusual symptoms that complicate the diagnostic evaluation. Herein, we describe the case of a 70-year-old patient with a long-lasting low-grade fever due to a large left atrial myxoma revealed during a transthoracic echocardiography.

The natural history of arrhythmogenic right ventricular cardiomyopathy.

The authors describe the case of a 66-year-old woman with arrhythmogenic right ventricular dysplasia masqueraded as dilated cardiomyopathy. Her medical history included recurrent episodes of syncope beginning at the age of 28. The natural history of the disease is discussed.

Prevalence of paroxysmal atrial fibrillation in Brugada syndrome: a case series and a review of the literature.

OBJECTIVE: The present study aimed at investigating the incidence of paroxysmal atrial fibrillation in 10 patients with spontaneous or induced type 1 electrocardiographic pattern of Brugada syndrome (three with syncopal episodes and seven asymptomatic). Both clinical entities are closely associated with changes in autonomic modulation and, particularly, with increased vagal tone. METHODS: Transthoracic echocardiography, exercise treadmill test and 24-h Holter recordings were performed to all patients. RESULTS: Episodes of atrial fibrillation were recorded in 2/10 patients (20%). These patients suffered from syncopal episodes, exhibited a positive electrophysiological study, and finally received an implantable cardioverter-defibrillator. CONCLUSIONS: The present case series points out a high incidence of paroxysmal atrial fibrillation predominantly in symptomatic patients with type 1 electrocardiographic pattern of Brugada syndrome, indicating that the presence of atrial tachyarrhythmias may reflect an advanced stage of the disease. The prognostic significance of paroxysmal atrial fibrillation, particularly in asymptomatic patients with an electrocardiographic pattern consistent with Brugada syndrome requires further evaluation. Physicians should always be aware of Brugada syndrome in young patients with lone atrial fibrillation, especially in those with a history of syncope.

Brugada electrocardiographic pattern induced during febrile state with marked leukocytosis.

Several agents and conditions have been reported to unmask or accentuate the electrocardiographic pattern of Brugada syndrome including fever. At a molecular level, sodium channels have been showed to be temperature dependent. Herein, we describe a case of Brugada electrocardiographic pattern unmasked during febrile state and marked leukocytosis.

Anomalous origin of the entire coronary system with separate ostia within the right sinus of valsalva: a rare congenital anomaly and a review of the literature.

Congenital coronary artery malformations occur infrequently in the general population. In this report, we describe a rare case of anomalous origin of all three coronary arteries from separate ostia within the right coronary sinus.

Early repolarization syndrome: is it always benign?

Early repolarization syndrome is a well-recognized idiopathic electrocardiographic phenomenon characterized by prominent J wave and ST-segment elevation predominantly in left precordial leads. The syndrome shares remarkable cellular, ionic, and electrocardiographic similarities with the Brugada syndrome and idiopathic ventricular fibrillation (a variant of the Brugada syndrome with ST-segment elevation in inferior leads). Although early repolarization syndrome is considered a benign entity, its arrhythmogenic potential still remains unknown. We report the case of a 39-year-old male with a family history of sudden death and an electrocardiogram consistent with early repolarization syndrome. Diagnostic dilemmas are discussed.

Hypertrophic cardiomyopathy in a patient with Crohn's disease: a case report.

Cardiac manifestations of Crohn's disease are rare; the most common is pericarditis. In the present report we briefly describe a 56-year-old man with Crohn's disease who presented to the emergency department due to paroxysmal atrial flutter. A transthoracic echocardiographic study revealed asymmetric left ventricular hypertrophy without outflow pressure gradient. Reviewing the literature, hypertrophic cardiomyopathy has not been previously described in patients with Crohn's disease.

QT interval prolongation associated with venlafaxine administration.

A significant number of non-antiarrhythmic drugs including psychotropic agents have been shown to prolong cardiac repolarization increasing the risk for torsade de pointes ventricular tachycardia. We briefly describe a 60-year-old woman who admitted to the hospital due to hypertension and mild dyspnea having a prolonged QT interval (QTc: 582 ms). The patient had a known history of depression treated with venlafaxine. The QT interval normalised a few days after cessation of the antidepressant agent. This is the first report of venlafaxine-induced QT interval prolongation.

QT interval prolongation and torsade de pointes associated with indapamide.

Direct blockade of the delayed rectifier repolarising potassium current is the major underlying mechanism of drug-induced QT interval prolongation. Indapamide is a well known blocker of the slow component of the delayed rectifier current leading to prolongation of cardiac repolarization. The case of an acquired long QT and torsade de pointes ventricular tachycardia in a woman with systemic lupus erythematosus and hypertension receiving prednisolone and indapamide, respectively, is described in the present report.

Spontaneous coronary artery dissection associated with oral contraceptive use: a case report and review of the literature.

Spontaneous coronary artery dissection (SCAD) represents a rare cause of acute coronary syndromes with complex pathohysiology. We briefly describe a 50-year-old woman, without traditional cardiovascular risk factors, hospitalized for an acute ST-elevation myocardial infarction and treated with thrombolytic therapy. Notably, the patient was on oral contraceptives for the past 10 years. Coronary angiography showed a dissection of the distal left anterior descending artery. She was treated conservatively and her clinical status improved without evidence of continuing ischemia, while a repeated catheterization 6 months later showed a complete resolution of the dissection. It has been speculated that the female hormones may be responsible for the increased incidence of SCAD among women particularly during the peripartum period or during the exogenous administration of such agents. A systematic review of the literature revealed 4 further cases reporting an association of SCAD with oral contraceptive use.

Acute myocardial infarction with normal coronary arteries in a patient with Hodgkin's disease: a late complication of irradiation and chemotherapy.

We describe the case of a 31-year-old man who experienced an acute myocardial infarction 16 years after undergoing radiation and vinca alkaloid therapy for Hodgkin's disease. Even though coronary artery disease is a well-established complication after mediastinal radiation therapy, this adult patient had normal coronary angiographic results, with no traditional risk factors for coronary artery disease, and no hematologic or other abnormality associated with hypercoagulability.

Effect of atrial pressure increase on sinus node automaticity.

There is evidence suggesting that atrial electrophysiological properties may be changed by an acute increase in atrial pressure. The aim of the present study was to investigate the effect of alteration, in atrial pressure on sinus node recovery time. Twelve patients (8 men and 4 women, mean age 61.3 +/- 14.1 years) were included in this study. None of the patients had organic heart disease. Sinus node recovery time (SNRT) was measured following atrial pacing and atrioventricular (AV) pacing at sequential cycle lengths of 600, 545, 500, 461, 428, and 400 ms with two different AV intervals (150, 0 ms). Peak and minimal atrial pressure increased significantly from 8.5 +/- 2.8 to 20.1 +/- 2.9 mmHg (11.56 +/- 3.8 to 27.3 +/- 3.9 cmH2O) ( P=0.001) and from 2.06 +/- 1.69 to 5.33 +/- 2.9 mmHg (2.8 +/- 2.29 to 7.2 +/- 3.9 cmH2O), respectively (P=0.002) during AV interval modification. Sinus node recovery time did not change despite the increase in atrial pressure. Autonomic blockade had no effect on SNRT. This study demonstrates that atrial pressure increase does not significantly affect sinus node automaticity expressed by SNRT.

The Contribution of the Left Atrioventricular Plane Displacement During Low Dose Dobutamine Stress Echocardiography in Predicting Recovery of Left Ventricular Dyssynergies.

The aim of this study was to assess the significance of the left systolic atrioventricular (AV) plane displacement during low dose dobutamine stress echocardiography (DSE), in predicting the recovery of left ventricular dyssynergies after revascularization. In 30 infarctiers with left ventricular dysfunction scheduled for RE (14 percutaneous transluminal coronary angioplasty and 16 coronary artery bypass graft) and in 25 age- and sex-matched healthy subjects, a DSE, using a 16 ventricular segment model and a four-grade scoring system for the assessment of regional wall motion of the left ventricle was performed. Prior and during DSE, the left systolic AV plane displacement was recorded from the apical four- and two-chamber views, by M-mode echo, at four left ventricular sites, corresponding to the septal, lateral, anterior, and inferior walls, both in patients and controls. The study was repeated in all patients 101 +/- 14 days after successful revascularization. Healthy subjects showed a significant increase of left systolic AV plane displacement at all left ventricular sites during dobutamine infusion (DI) (P < 0.001). Patients also exhibited a significant maximum increase of left systolic AV plane displacement during DSE only in the dyssynergic sites with functional improvement in the postrevascularization echocardiogram (P < 0.001). In the remaining dyssynergic sites, without functional improvement after revascularization, the left systolic AV plane displacement did not change (P > 0.05). Selecting a maximum LAVPD increase of >2 mm at any site of the left ventricule to predict recovery of the regional ventricular dyssynergies, results in a sensitivity of 91%, specificity of 83%, positive predictive value of 88%, and negative predictive value of 87%. When two-dimensional DSE was used for the detection of reversible dysfunction, sensitivity and specificity were found to be 81.5% and 87.5%, respectively, while the positive and negative predictive values were 90% and 78%, respectively. When the two methods were in agreement the sensitivity was 90%, the specificity 100%, and the positive and negative predictive values were 100% and 84.2%, respectively. The assessment of left systolic AV plane displacement during DI constitutes a new, simple, and accurate method in the prediction of left ventricular dyssynergy recovery after revascularization. The combination of this method and two-dimensional DSE are basic predictor markers of viability of dysfunctional myocardium. (ECHOCARDIOGRAPHY, Volume 13, November 1996)