Case - Hypertension with LV Dysfunction

Written by Gabriel Altit - August 10th, 2025. 

This is the case of a term infant weighing 3.6 kg tha had been transferred to our center at day of life (DOL) 3 for evaluation and management of hyperbilirubinemia and a metabolic acidosis of unclear origin. The baby presented with a significantly elevated ammonia level of 351 µmol/L. Prompt initiation of scavenger therapy (sodium phenylacetate and sodium benzoate) and arginine,led to rapid normalization of ammonia without the need for dialysis. Despite this, metabolic acidosis persisted, likely due to a prolonged catabolic state. Enteral feeds using a propionic acidemia-free formula, intravenous lipids, and high dextrose concentrations were introduced to support metabolic recovery. During this period, the baby developed progressive neurological symptoms including jittery movements, hypotonia, and gasping-like respirations. Telemetry confirmed status epilepticus, and the baby required multiple anti-seizure medications including phenobarbital, fosphenytoin, midazolam, keppra, topiramate, and ketamine. The seizures were eventually controlled after 24–48 hours of intensive therapy. Concurrently, the baby experienced vasoplegia likely secondary to the sedative and anti-seizure regimen, necessitating cardiovascular support with dopamine, norepinephrine, and hydrocortisone. Blood pressure normalized following this intervention, and the baby was successfully weaned off inotropes. The patient had confirmed propionic acidemia. Once the vasopressors were weaned completely and hydrocortisone was stopped, the medical team requested a targeted neonatal echocardiography (TNE), in order to evaluate for the hemodynamics and confirm stability of the cardiac function. 

At the time of the TNE, the neonatal hemodynamics team noted that the blood pressure was a systolic pressure of 95 mmHg and diastolic of 75 mmHg measured via umbilical arterial line. At the time, the infant had good pulses and was intubated on minimal settings on the conventional mechanical ventilation with 21% FiO2. The TNE is as below. 

This case highlights a term infant weighing 3.6 kg who demonstrated signs of left ventricular (LV) dysfunction. The peak longitudinal strain was decreased at -14%. The TNE evaluation revealed a mildly dilated LV with an ejection fraction of 37–38%, accompanied by mild mitral regurgitation (MR) and mild to moderate aortic insufficiency (AI). These valvular findings were likely secondary to LV dilation. Despite the reduced systolic function, the left ventricular output (LVO) was preserved, with antegrade flow noted in the descending aorta. Clinically, the infant was well perfused, with a normal lactate level of 2.1 mmol/L and good urine output. The cardiac dysfunction was likely multifactorial. At the time of evaluation, the infant was hypertensive, with systolic blood pressures ranging from 90 to 95 mmHg—elevated for a 12-day-old term neonate—suggesting a high afterload state. This was compounded by a prior episode of severe metabolic acidosis, which is poorly tolerated by the myocardium, and exposure to significant vasopressor therapy including dopamine, norepinephrine, and hydrocortisone. These two factors, along with the underlying metabolic disorder (propionic acidemia), may have contributed to the observed LV dysfunction. AI likely reduced forward flow in the ascending aorta, while MR may have elevated left atrial (LA) pressure. However, there were no echocardiographic signs of LA hypertension: no significant LA dilation, normal pulmonary venous Doppler flow, and a bidirectional PFO suggesting similar LV and RV end-diastolic pressures. Additionally, the infant had mildly elevated right ventricular systolic pressure (RVSP) estimated at 45 mmHg via tricuspid regurgitation jet, approximately half systemic. Given the preserved perfusion, adequate urine output, and absence of overt LA hypertension, the decision was made to initiate milrinone therapy. This aimed to reduce systemic vascular resistance (SVR) and support LV contractility. A repeat targeted neonatal echocardiogram (TNE) was recommended 48 hours after starting milrinone to reassess cardiac function and response to therapy.

After 24 hours of milrinone infusion

LV Function has completely normalized on 48 hours of milrinone. The systolic blood pressure has dropped to 65-70 mmHg, which is within normal limit for age. The baby remained well perfused with good urine output. The AI and MR had disappeared by colour doppler. 

Normalized LV function by Simpsons at 48 hours of Milrinone. With EF estimated at 71%.

This case outlines how systemic hypertension and increased LV afterload may contribute to LV dysfunction. Systemic hypertension can contribute to left ventricular (LV) dysfunction through several interconnected mechanisms. Elevated systemic blood pressure increases the afterload—the resistance the LV must overcome to eject blood during systole. This heightened workload forces the myocardium to contract more forcefully, which over time can lead to myocardial strain, impaired contractility, and eventual systolic dysfunction. In neonates, whose myocardial fibers are less mature and more sensitive to pressure changes, this effect can be particularly pronounced. In the context of this case, the infant was hypertensive with systolic pressures between 90 and 95 mmHg, which is elevated for a term neonate at 12 days of life. This increased afterload likely contributed to the observed LV dilation and reduced ejection fraction (37–38%). The presence of mild mitral regurgitation and moderate aortic insufficiency may have further exacerbated the volume and pressure burden on the LV, compounding the dysfunction. Additionally, LV dilatation can impair coronary perfusion by increasing transmural pressure, reducing oxygen delivery to the myocardium and further compromising its function. Moreover, the infant had previously experienced severe metabolic acidosis and was exposed to multiple vasopressors, both of which are known to negatively impact myocardial performance. Acidosis impairs cellular metabolism and contractile function, while vasopressors can increase afterload and alter myocardial oxygen demand. These factors, combined with the underlying metabolic disorder (propionic acidemia), likely created a multifactorial insult to the LV, resulting in the observed dysfunction. Initiation of milrinone was a strategic choice to reduce systemic vascular resistance and support inotropy, aiming to improve cardiac output and reduce myocardial stress.