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We report the case of a 16-year-old boy with cardiomyopathy induced by inappropriate sinus tachycardia (IST). The patient was resistant to treatment with conventional rate-decreasing medications. Therapy with the selective sinus node I(f) current inhibitor ivabradine was started. After 3 months of ivabradine therapy, an improvement in ejection fraction and a successful decrease in heart rate were observed. No side effects occurred. We suggest that ivabradine, currently used to treat stable angina, could be considered as a second-line treatment in patients with symptomatic and refractory IST.

BACKGROUND: Sacubitril/valsartan was demonstrated to reduce hospitalization rate and mortality in patients with heart failure with reduced ejection fraction. Data on the effects of sacubitril/valsartan in patients with a systemic right ventricle are still lacking. METHODS: Patients with transposition of the great arteries following Senning/Mustard procedure or congenitally corrected transposition of the great arteries with impaired systemic right ventricle systolic function were prospectively included. Primary end points included sacubitril/valsartan safety and efficacy. Primary efficacy end points were NT-proBNP (N-terminal pro-B-type natriuretic peptide) and systolic function improvement. Secondary end points included New York Heart Association class, 6-minute walking distance, and quality of life change. RESULTS: Fifty patients (38±12 years, 60% male, 35% congenitally corrected transposition of the great arteries) were included and followed for 1 year. No major adverse events occurred. Two (4%) patients ceased treatment due to hypotension and 1 (2%) developed a nephrotic syndrome. The target dose was reached in 20 (42%) patients. NT-proBNP values decreased significantly immediately after treatment initiation, while returned to baseline at 1 year. Echocardiography showed progressive fractional area change increase (29.2±5.8 versus 34.9±5.1%; P <0.001), and right ventricle global longitudinal strain (−13.9 [−15.1, −11.8] versus −15.3 [−17.2, −13.4]%; P <0.001) and free-wall global longitudinal strain (−14.3 [−17.3, −12.3] versus −17.2 [−19.3, −15.8]%; P <0.001) raise, whereas tricuspid regurgitation severity improved only in transposition of the great arteries patients ( P =0.006). Moreover, 3-dimensional echocardiography demonstrated right ventricle volumes reduction (end-diastolic volume: 181±63 versus 156±50 mL; P =0.002; end-systolic volume: 117±48 versus 89±33 mL; P <0.001), and significantly increased systemic right ventricle ejection fraction (35.6±8.1 versus 41.5±7.5%; P <0.001). Clinical improvement was suggested by New York Heart Association class change ( P <0.001), increased 6-minute walking distance (425 [333, 480] versus 500 [443, 560] m; P <0.001) as well as improved quality of life at 1-year follow-up. Beneficial effects were observed irrespective of the underlying anatomy and were more pronounced in those on target dose. CONCLUSIONS: Our data showed that sacubitril/valsartan is well tolerated and is associated with systemic right ventricle remodeling and improved systolic function as well as improved clinical status, supporting its use in this complex population.

Propionyl-L-carnitine was given intravenously to ten patients with chronic ischemic heart disease who had normal left ventricular function and had not had a previous myocardial infarction. Subsequently, pulmonary and systemic circulation, left ventricular function, and the relationship between the ventricle and afterload were evaluated. This drug, at a dose of 15 mg/kg, improves ventricular function by easing the load and by enhancing cardiac efficiency. The ejection impedance is reduced with a consequent increase in stroke volume as a result of a) a decrease in systemic and pulmonary resistance and b) an increase in arterial compliance. Arterial pressure is maintained due to an increase in total external heart power. Since the tension time index shows a proportionally smaller increase in the energy requirement, it follows that cardiac efficiency has been improved and ventricle-afterload matching is optimal. These results suggest but do not prove that propionyl-L-carnitine exhibits a positive inotropic property.