L-arginine reduces heart rate and improves hemodynamics in severe congestive heart failure.

BACKGROUND: Stimulated endothelium-derived relaxing factor-mediated vasodilation and conduit artery distensibility are impaired in congestive heart failure (CHF). L-arginine could have a potentially beneficial role in CHF, acting through the nitric oxide (NO)-L-arginine pathway or by growth hormone increment. HYPOTHESIS: This study was undertaken to investigate the effects of L-arginine on heart rate, hemodynamics, and left ventricular (LV) function in CHF. METHODS: In seven patients (aged 39 +/- 8 years) with CHF, we obtained the following parameters using echocardiography and an LV Millar Mikro-Tip catheter simultaneously under four conditions: basal, during NO inhalation (40 ppm), in basal condition before L-arginine infusion, and after L-arginine intravenous infusion (mean dose 30.4 +/- 1.9 g). RESULTS: Nitric oxide inhalation increased pulmonary capillary wedge pressure from 25 +/- 9 to 31 +/- 7 mmHg (p < 0.05), but did not change echocardiographic variables or LV contractility by elastance determination. L-arginine decreased heart rate (from 88 +/- 15 to 80 +/- 16 beats/min, p<0.005), mean systemic arterial pressure (from 84 +/- 17 to 70 +/- 18 mmHg, p < 0.007), and systemic vascular resistance (from 24 +/- 8 to 15 +/- 6 Wood units, p<0.003). L-arginine increased right atrial pressure (from 7 +/- 2 to 10 +/- 3 mmHg, p<0.04), cardiac output (from 3.4 +/- 0.7 to 4.1 +/- 0.8 l/min, p < 0.009), and stroke volume (from 40 +/- 9 to 54 +/- 14 ml, p < 0.008). The ratios of pulmonary vascular resistance to systemic vascular resistance at baseline and during NO inhalation were 0.09 and 0.075, respectively, and with L-arginine this increased from 0.09 to 0.12. CONCLUSION: L-arginine exerted no effect on contractility; however, by acting on systemic vascular resistance it improved cardiac performance. L-arginine showed a negative chronotropic effect. The possible beneficial effect of L-arginine on reversing endothelial dysfunction in CHF without changing LV contractility should be the subject of further investigations.

Clinical outcome after left ventricular surgical remodeling in patients with idiopathic dilated cardiomyopathy referred for heart transplantation: short-term results.

BACKGROUND: Left ventricular partial ventriculectomy (LVPV), an unconventional operation to reverse some aspects of the cardiac remodeling, has been proposed for treatment of congestive heart failure. METHODS AND RESULTS: Twenty-four patients (age 46+/-9 years) referred to heart transplantation underwent isolated LVPV or LVPV associated to valve annuloplasty. Patients were in New York Heart Association functional class IV (15) or III (9) due to idiopathic dilated cardiomyopathy. Functional class, left and right ventricular ejection fraction (radionuclide), left ventricular end-diastolic and end-systolic diameter, and fractional shortening (by echocardiography), and hemodynamic variables were determined. The mean follow-up was 474+/-174 days. Survival at 30, 180, and 365 days was 92+/-6%, 67+/-10%, and 63+/-10%, respectively. Nine patients died, and the cause was associated with arrhythmias in 4 patients. The left ventricular end-diastolic diameters before and at 23+/-14 days, 188+/-27, and 365+/-14.8 days of follow-up were 82.6+/-9.8, 68.9+/-7.8, 69.9+/-6.9, and 70+/-5.3 mm, respectively (P=0.0001). The left ventricular end-systolic diameters were 73.5+/-7.4, 55.9+/-7.5, 57.4+/-7.8, and 55+/-5.5 mm (P=.0001). Fractional shortenings were 13+/-3, 19+/-4, 18+/-5, and 22+/-2%, respectively (P=.0001). The left ventricular ejection fractions before and 18+/-14, 188+/-26, and 369+/-3.6 days after the surgery were 17.2+/-4.7, 24.5+/-8.3, 24.5+/-7.4, and 23.7+/-6.1%, respectively (P=.004). The right ventricular ejection fractions were 20.5+/-6.2, 27.9+/-8.4, 28.2+/-10.1, and 27.4+/-7.3% (P=0.02). Pressures were unchanged. There was improvement in cardiac index from 2.11+/-0.52 to 2.53+/-0.64 L/min (P=.0037). Norepinephrine blood levels reduced from 702+/-258 to 439+/-307 pg/mL (P=.001). Most surviving patients presented improvement in functional class. Sustained ventricular tachycardias were observed in 9 patients (38%). CONCLUSIONS: The left ventricular partial ventriculectomy may improve the left and right ventricular function, functional class, and cardiac output. These initial results were associated to high prevalence of sustained ventricular tachycardia. The ventriculectomy introduces the concept that reduction of left ventricular chamber diameter may improve cardiac function in heart failure. Further progress is necessary to improve the results and evaluate its proper role in the management of heart failure.