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Titolo:
Exercise-induced QTc-interval changes for predicting improvement in regional blood flow in ischemic myocardium and cardiac output after coronary angioplasty in patients with right bundle-branch block
Autore:
Watanabe, T; Michihata, T; Yamanaka, H; Akutsu, Y; Okazaki, O; Katagiri, T; Harumi, K;
Indirizzi:
Showa Univ, Sch Med, Dept Internal Med 3, Tokyo 142, Japan Showa Univ Tokyo Japan 142 ch Med, Dept Internal Med 3, Tokyo 142, Japan Showa Univ, Sch Med, Dept Surg 1, Tokyo 142, Japan Showa Univ Tokyo Japan 142 Univ, Sch Med, Dept Surg 1, Tokyo 142, Japan Int Med Ctr Japan, Div Cardiol, Tokyo, Japan Int Med Ctr Japan Tokyo Japan Med Ctr Japan, Div Cardiol, Tokyo, Japan Nakano Natl Chest Hosp, Tokyo, Japan Nakano Natl Chest Hosp Tokyo JapanNakano Natl Chest Hosp, Tokyo, Japan
Titolo Testata:
CLINICAL CARDIOLOGY
fascicolo: 5, volume: 23, anno: 2000,
pagine: 359 - 364
SICI:
0160-9289(200005)23:5<359:EQCFPI>2.0.ZU;2-4
Fonte:
ISI
Lingua:
ENG
Soggetto:
POSITRON-EMISSION-TOMOGRAPHY; AMERICAN-HEART-ASSOCIATION; ST-SEGMENT DEPRESSION; ARTERY DISEASE; N-13 AMMONIA; ELECTROCARDIOGRAPHY; MEN;
Keywords:
QTc interval; right bundle-branch block; percutaneous transluminal coronary angioplasty; regional myocardial blood flow; cardiac output;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Citazioni:
24
Recensione:
Indirizzi per estratti:
Indirizzo: Watanabe, T Univ Texas, Houston Hlth Sci Ctr, Dept Internal Med, Div Cardiol, 6431 Fannin,MSB 6-039, Houston, TX 77030 USA Univ Texas 6431 Fannin,MSB6-039 Houston TX USA 77030 7030 USA
Citazione:
T. Watanabe et al., "Exercise-induced QTc-interval changes for predicting improvement in regional blood flow in ischemic myocardium and cardiac output after coronary angioplasty in patients with right bundle-branch block", CLIN CARD, 23(5), 2000, pp. 359-364

Abstract

Background: We have previously shown that QT-interval changes are more useful than ST-T changes in evaluating the severity of exercise-induced myocardial ischemia in patients with right bundle-branch block (RBBB). Hypothesis: The purpose of this study was to evaluate whether the improvement in regional myocardial blood flow (RMBF) in ischemic areas and cardiac output after percutaneous transluminal coronary angioplasty (PTCA) can be predicted by exercise-induced QT-interval changes prior to PTCA. Methods: The RMBF and cardiac output were quantified with nitrogen-13 ammonia positron emission tomography at rest and during exercise in 20 patientswith RBBB and ischemic heart disease before and 6 months after PTCA, and in 9 healthy volunteers. Results: Before PTCA, exercise-induced prolongation by < 20 ms or shortening of the Bazett-corrected QT (QTc) interval (454 +/- 38 to 451 +/- 41 ms, p = NS) was observed in 13 patients (Group 1) and prolongation by greater than or equal to 20 ms (429 +/- 44 to 466 +/- 50 ms, p < 0.002) was observedin 7 (Group 2). The number of regions of exercise-induced ischemia was significantly greater in Group 2 than in Group 1 (4.0 +/- 1.2 vs. 2.1 +/- 1.2,p < 0.01). The RMBF in regions of exercise-induced ischemia and cardiac output at rest was not significantly different between Groups 1 and 2, whereas during exercise both the parameters were significantly lower in Group 2 than in Group 1 (both p < 0.05). After successful PTCA, RMBF both at rest and during exercise improved significantly in Group 1 (0.67 +/- 0.04 to 0.71 /- 0.06 ml/min/g, 0.74 +/- 0.05 to 0.84 +/- 0.08 ml/mim/g; both p < 0.0001), but did not improve significantly in Group 2 (0.63 +/- 0.05 to 0.65 +/- 0.07 ml/min/g, 0.65 +/- 0.04 to 0.69 +/- 0.11 mi! min/g; both p = NS). Cardiac output during exercise improved significantly in Group 1 (6.4 +/- 0.7 to 7.4 +/- 0.9 l/min, p < 0.002) but not in Group 2 (5.7 +/- 0.6 to 5.9 +/- 0.6 l/min; p =NS). Conclusions: Our results suggest that the marked prolongation of the QTc interval induced by pre-PTCA exercise may predict a lack of improvement in RMBF in ischemic areas and cardiac output after PTCA in patients with RBBB and ischemic heart disease.

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Documento generato il 22/01/20 alle ore 07:17:22