Cyclic variation in myocardial gray level as a marker of viability in man. A videodensitometric study.
Experimental and human studies have shown that a preserved cyclic (diastolic-to-systolic) echoreflectivity variation, assessed by radiofrequency sampling of backscatter signal with non-commercially available prototypes, identifies viability in a myocardial segment with a resting dyssynergy. The objective of this study was to assess whether a videodensitometric analysis of myocardial gray level variation during cardiac cycle might identify viable but dyssynergic myocardium in a clinical setting. Thirty-four patients with a resting dyssynergy (akinesis in 26, marked hypokinesis in eight) in the septum and/or inferno-posterior wall were evaluated by videodensitometry. All echo studies were performed with commercially available instruments in the long axis parasternal view, with quantitative analysis of gray levels performed off-line on digitized images. Segmental wall motion was assessed with a 16 segment model of the left ventricle, each scored from 1, normal, to 4, dyskinetic. A follow-up echo study was obtained in all patients > 4 weeks after successful revascularization (in 22 by angioplasty, in 12 by bypass surgery). Two groups of segments were identified: 18 viable segments (contractile improvement of 1 grade or more in resting function after revascularization); 16 necrotic segments (no contractile improvement in resting function after revascularization). The % cyclic variation was higher in viable vs necrotic segments (26 +/- 16 vs 1 +/- 13%, P < 0.01), in spite of similar % systolic thickening (5 +/- 5 vs 4 +/- 6%, P = ns) and end-diastolic thickness (10 +/- 2 vs 10 +/- 2 mm, P = ns). When individual patient analysis was performed, % cyclic variation was below the 95% confidence limits obtained from normal control regions (n = 34; % cyclic variation = 38 +/- 14) in two out of 18 viable and in 14 out of 16 necrotic segments. A cut-off of > or = 9.4% cyclic variations in a dyssynergic segment yielded 89% sensitivity and 88% specificity for predicting functional recovery following successful revascularization. In conclusion, viable dyssynergic myocardial segments show a cyclic gray level variation at rest, which can be detected by simple videodensitometric analysis, much less technologically demanding than radiofrequency backscatter evaluation.
Marini
C
C
CNR, Institute of Clinical Physiology, Pisa, Italy.
Picano
E
E
Varga
A
A
Marzullo
P
P
Pingitore
A
A
Paterni
M
M
D002470:Cell Survival; D003327:Coronary Disease / Q000503:physiopathology*; D003720:Densitometry; D003971:Diastole; D004452:Echocardiography; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D009206:Myocardium / Q000473:pathology; D010507:Periodicity; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013599:Systole; D014741:Video Recording