Non-ischemic Myocardial Disease Research Articles

Ischemic and Nonischemic Patterns of Diastolic Abnormalities during Isometric Handgrip Exercise

This study establishes the clinical value of the recently introduced handgrip-apexcardiographic test (HAT) as an additional tool for distinguishing exercise-induced diastolic abnormalities in coronary artery disease (CAD) patients from those in patients with hypertrophic cardiomyopathy (HCM). This stress test reliably assessing differences in diastolic indices during handgrip between 305 healthy volunteers and 39 patients with CAD without prior infarction as well as 17 patients with HCM showed two different patterns of handgrip-induced pathological changes in these indices. An 'ischemic diastolic response' was empirically defined by the presence of either a handgrip-induced more than doubling of a resting normal relative A wave to total height of the apex-cardiogram (ischemic compliance response) or a pathological prolongation of a resting normal total apexcardiographic relaxation time (ischemic relaxation response); whereas a 'nonischemic diastolic response' was defined by the presence of a positive HAT and by absence of the above-mentioned ischemic criteria. An ischemic pattern of diastolic abnormalities was present in 72% of CAD patients, whereas 94% of HCM patients showed a 'nonischemic' diastolic response. These results confirm that in CAD patients there is a typical response of diastolic apexcardiographic indices to isometric stress and, therefore, this simple stress test could be potentially useful in separating these patients from those with nonischemic myocardial disease states.

Double-Nuclide Study of the Myocardium Using 201TI and 123l-Labeled Fatty Acids in Nonischemic Myocardial Diseases)

Metabolic impairment and perfusion abnormalities are known to occur in hypertensive heart disease (HHD) and in cardiomyopathies. Free fatty acid (FFA) extraction is severely inhibited in a number of pathobiochemical reactions. This parameter was assessed using the radiolabeled FFA analogue 123I-(p-iodo-phenyl-)-pentadecanoic acid (IPPA) and 201Tl as perfusion marker, both of them injected at maximal physical workload. The regional extraction fraction of IPPA (IPPA-EF) was estimated by relating the regional IPPA and 201Tl uptake to each other. In HHD (normal coronary arteries) with posterior wall thickness less than or equal to 12 mm IPPA-EF was 77 +/- 18% (SD) in septum and 92 +/- 17% in the posterolateral wall (N = 13), with thickness of greater than 12 mm 60 +/- 23% in septum and 61 +/- 20% in the posterolateral wall (N = 8) when compared with IPPA-EF in normal subjects (= 100%, N = 9). In hypertrophic cardiomyopathy (HCM) IPPA-EF averaged 51 +/- 20% in septum and 87 +/- 10% in the posterolateral wall (N = 11). In these patient groups no systematic regional changes in 201TI uptake were observed. In dilated cardiomyopathy (DCM) both IPPA-EF and 201Tl uptake showed distinct regional variations and a great interindividual variability with a mean IPPA-EF reduction of 12% (N = 9). Thus, IPPA uptake in primarily non-ischemic myocardial disease may already be compromised when 201Tl uptake is unchanged. The double-nuclide method for IPPA-EF determination allows to eliminate the influence of flow in FFA imaging and enhances the potential of scintigraphy in the differential diagnosis of HHD versus coronary artery disease.