Complex Arrhythmias Due to Reversible Causes.

Abnormalities in cardiac rhythm are caused by disorders of impulse generation, conduction, or a combination of the 2, and may be life-threatening because of a reduction in cardiac output or myocardial oxygenation. Cardiac arrhythmias are commonly classified as tachycardias (supraventricular or ventricular) or bradycardias. Bradycardias are uncommon in the critically ill patient and often are caused by an underlying reversible disorder (eg, hyperkalemia, drug toxicity).

[Dronedarone: a real innovation or a mere second-best choice? How to find the way among guidelines, regulatory agencies and daily clinical practice].

Dronedarone is the antiarrhythmic drug with the most complete and wide literature preceding its marketing. Most of these studies showed a good efficacy along with an excellent risk profile, especially in low- and medium-risk patients. Recently, updates of European, American and even Italian guidelines gave dronedarone its own spot into the antiarrhythmic armamentarium, recommending its use both for rhythm control and rate control in non-permanent atrial fibrillation.

[Association between parachute mitral valve and Down's syndrome. Report of a case].

The trisomy 21 form of Down's syndrome is the most common human chromosomal aberration. Congenital heart disease is found in as many as 50 per cent of patients with this disorder. The two most common cardiac lesions in Down's syndrome are septal ventricular defect and endocardial cushion defect.

Histologic evidence of myocardial damage in apparently healthy subjects with ventricular arrhythmias and myocardial dysfunction.

The association of ventricular arrhythmias and myocardial dysfunction could be considered an early step toward cardiomyopathy; therefore, we studied 28 patients in NYHA class I and II, characterized by complex ventricular arrhythmias (VA) on 24-h Holter monitoring and volumetric and/or contractile abnormalities on a standard two-dimensional echocardiogram (2-D echo). All patients underwent radioisotopic angiography, 20 patients complete hemodynamic study, and 15 patients endomyocardial biopsy. Ambulatory ECG monitoring showed the presence of frequent premature ventricular contractions in 14 patients (50%) and episodes of ventricular tachycardia in 16 patients (57%).

Evaluation of rate-responsive pacemakers by transesophageal Holter monitoring of spontaneous atrial rate.

One of the most important problems in rate responsive (RR) pacing is the clinical experimental evaluation of the reliability of various sensors. In particular, it is difficult to test their sensitivity and specificity during daily activity of the patients. Atrial rate, when present and normal, is the most physiological marker of metabolic requirements, but sometimes it is impossible to analyze the P wave in ventricular paced rhythm during routinely performed tests (e.