AV delay optimization and management of DDD paced patients with dilated cardiomyopathy.

Ten DDD paced patients, suffering from dilated cardiomyopathy in the NYHA functional classes III or IV were studied by means of Doppler echocardiography at different programmed values of atrioventricular (AV) delay (200, 150, 120, 100, and 80 msec). The following variables were evaluated: LV diameter, ejection fraction, mitral and aortic flow velocity integrals, and stroke volume. During VDD pacing, a resting AV delay associated with the best diastolic filling and systolic function was identified and programmed individually.

[The viable myocardium: metabolic, diagnostic and therapeutic aspects].

The term stunned myocardium is used to indicate a reversible post-ischemic dysfunction of the ventricular mechanism which may persist for hours, days or weeks after the restoration of coronary flow following spontaneous or pharmacological thrombolysis, transluminal coronary angioplasty, aorto-coronary bypass and ischemic attacks. Hibernating myocardium is used to describe a depression of ventricular contractility in the presence of chronic hypoperfusion which may be reversed following revascularization as a result of aorto-coronary by-pass surgery. Three biochemical and physiopathological hypotheses are currently acknowledged to explain the phenomenon of stunning: the hypothesis of free oxygen radicals, the hypothesis related to an energy deficit and that involving a calcium overload.

[A critical review of the stable changes in ventricular repolarization in ischemic cardiopathy. A correlation with the angiographic findings].

Unknown is the significance of the abnormalities of repolarization observed at rest in patients with coronary artery disease (CAD) demonstrated by coronary angiography, except for ischemic episodes, myocardial infarction, left ventricular hypertrophy, electrolyte changes or pharmacological interactions. The chronic T wave inversion and ST segment depression are usually considered as an alteration due to ischemia ("chronic myocardial ischemia"); this definition is, in our opinion, erroneous, because myocardial ischemia is an acute episode caused by a sudden lack of balance between demand and availability of myocardial oxygen, corresponding to transient electrocardiographic alterations. Thus, the definition of "chronic myocardial ischemia" referred to stable abnormalities of repolarization is incorrect, because a "chronic" lack of balance between MVO2 and O2 availability would produce necessarily irreversible myocardial damage (necrosis).