Decreased post-myocardial infarction heart rate variability and cardiac denervation assessed by metaiodobenzylguanidine scintigraphy.

Decreased heart rate variability, assessed 2 weeks after uncomplicated acute myocardial infarction, is related to the extent of 1-123-metaiodobenzylguanidine-derived efferent sympathetic cardiac denervation. This postinfarction cardiac denervation could be the substrate of reduced postinfarction heart rate variability.

Detection of microinfarction in patients with unstable angina: study by 111In-antimyosin imaging.

To examine the incidence of a positive indium-111 antimyosin scintigraphy in patients with unstable angina, we prospectively examined 25 patients with unstable angina and 11 patients with stable angina. All patients were injected with 2 mCi of indium-111 on admission and planar scintigraphy was performed 48 h later. Symptoms and signs of ischemia indicating severity of ischemia were monitored during the period between injection and scanning.

Acute effects of external and internal pacing on ejection fraction in patients with severe cardiac failure.

The present study aims at evaluating the acute hemodynamic effects of external and internal (3 and 15 mA) pacing on 30 patients with severe cardiac failure. The global and regional ejection fraction were calculated by repeated radionuclide ventriculography at rest (control) and during increasing pacing rates. Blood pressure was measured at the end of each scintigraphy data acquisition period.

I-123 metaiodobenzylguanidine--thallium-201 mismatch following myocardial infarction.

Experimental data show that myocardial infarction (MI) results in regional depletion of myocardial catecholamines more extensively than necrosis. To investigate the extent of adrenergic denervation post MI in humans, we examined 16 patients, 59 +/- 12 years old, with recent (7-12 days) MI. Resting thallium-201 (201Tl) single photon emission computerized tomography (SPECT) imaging was performed to assess necrosis; metaiodobenzylguanidine I123 (MIBG) SPECT was used to evaluate adrenergic denervation.

Detection of viable tissue in healed infarcted myocardium by dipyridamole thallium-201 reinjection and regional wall motion studies.

Reinjection imaging with thallium-201 (Tl-201) may provide a convenient method of assessing myocardial viability. Twenty patients with a previous Q-wave healed myocardial infarction were examined to evaluate the detection of viable tissue in infarcted segments. All patients underwent to evaluate the detection of viable tissue in infarcted segments.