Pilot study to assess the influence of β-blockade on mitral regurgitant volume and left ventricular work in degenerative mitral valve disease
Pilot study to assess the influence of β-blockade on mitral regurgitant volume and left ventricular work in degenerative mitral valve disease
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DOI：
10.1161/circulationaha.108.770438
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发表时间：
2008-09-02
期刊：
影响因子：
37.8
通讯作者：
Cowan, Brett R.
中科院分区：
文献类型：
--
作者：
Stewart, Ralph A. H.;Raffel, Owen C.;Cowan, Brett R.
背景-降低左心室（LV）功能障碍或症状的可能性的药物治疗将使中度至重度退行性二尖瓣返流患者受益。本初步研究的目的是确定β受体阻滞剂对这些患者二尖瓣反流量和左室功的短期影响。方法和结果：在一项双盲交叉研究中，25例中度或重度退行性二尖瓣反流患者随机接受β 1选择性肾上腺素受体阻滞剂美托洛尔治疗（平均每日剂量，119 mg;范围23.75至190 mg）和安慰剂，持续14 +/- 3天。在每个治疗期结束时，通过心脏磁共振成像测量升主动脉血流量和LV每搏输出量，并计算二尖瓣返流量。使用β受体阻滞剂后，心率从65 +/- 10降低到10 +/- 7 bpm（平均值+/- SD），收缩压从138 +/- 18降低到16 +/- 12 mm Hg（两者均P < 0.0001）。左心室射血分数（从65 +/- 5%;变化，-0.6 +/- 2.7%; P = 0.3）或二尖瓣返流容积（从59 +/- 36 mL;变化，3 +/- 13 mL; P = 0.3）无显著变化，但前向每搏输出量从89 +/- 21增加5 +/- 11 mL（P = 0.03）。由于美托洛尔组心率较低，心输出量从5.68 +/- 1.04下降0.56 +/- 0.78 L/min（P = 0.001），但左室输出量下降幅度更大，从9.51 +/- 2.22下降1.30 +/- 1.08 L/min（P < 0.0001）。每分钟二尖瓣返流量从3.83 +/- 2.41降低0.74 +/- 1.00 L/min（P = 0.001）。β-受体阻滞剂导致左心室做功减少（平均值，21%; 95%置信区间，15 - 27）（P = 0.001）心输出量减少（平均9%; 95%置信区间，3至15）。结论-在这项试点研究中，在中度至重度退行性二尖瓣返流患者中，短期使用β受体阻滞剂治疗并没有改变二尖瓣每搏的收缩容积，但降低了LV作功。需要进一步的研究来确定β受体阻滞剂的长期治疗是否会减少进行性LV功能障碍和症状恶化。
Background-A medical treatment that decreases the likelihood of left ventricular (LV) dysfunction or symptoms would benefit patients with moderate to severe degenerative mitral regurgitation. The aim of this pilot study was to determine the short-term effects of a beta-blocker on mitral regurgitant volume and LV work in these patients.Methods and Results-Twenty-five patients with moderate or severe degenerative mitral regurgitation were randomized in a double-blind crossover study to the beta(1)-selective adrenergic blocker metoprolol (mean daily dose, 119 mg; range 23.75 to 190 mg) and placebo for 14 +/- 3 days. At the end of each treatment period, ascending aortic flow and LV stroke volume were measured by cardiac magnetic resonance imaging, and mitral regurgitant volume was calculated. On beta-blocker, heart rate decreased from 65 +/- 10 by 10 +/- 7 bpm (mean +/- SD) and systolic blood pressure decreased from 138 +/- 18 by 16 +/- 12 mm Hg (P < 0.0001 for both). No significant change occurred in LV ejection fraction (from 65 +/- 5%; change, -0.6 +/- 2.7%; P = 0.3) or mitral regurgitant volume (from 59 +/- 36 mL; change, 3 +/- 13 mL; P = 0.3), but forward stroke volume increased from 89 +/- 21 by 5 +/- 11 mL (P = 0.03). Because heart rate was lower on metoprolol, cardiac output decreased from 5.68 +/- 1.04 by 0.56 +/- 0.78 L/min (P = 0.001), but a greater decrease occurred in LV output, from 9.51 +/- 2.22 by 1.30 +/- 1.08 L/min (P < 0.0001). Mitral regurgitant volume per minute decreased from 3.83 +/- 2.41 by 0.74 +/- 1.00 L/min (P = 0.001). The decrease in LV work on beta-blocker (mean, 21%; 95% confidence interval, 15 to 27) was greater (P = 0.001) than the decrease in cardiac output (mean, 9%; 95% confidence interval, 3 to 15).Conclusions-In this pilot study, short-term treatment with a beta-blocker did not change mitral regurgitant volume per beat but decreased LV work in patients with moderate to severe degenerative mitral regurgitation. Further research is needed to determine whether longer-term treatment with beta-blockers will decrease progressive LV dysfunction and symptomatic deterioration.