Dynamic left ventricular outflow tract obstruction secondary to catecholamine excess in a normal ventricle

The Role of Left Ventricular Outflow Tract Peak Velocity Measurement in Patients With Sepsis and Septic Shock

Aim

To determine whether left ventricular outflow tract peak velocity is useful for the prediction of mortality in the early phase of sepsis or septic shock.

Materials and methods

Patients who were hospitalized in the emergency intensive care unit (ED-ICU) with the diagnosis of sepsis or septic shock were consecutively enrolled into two groups (sepsis and septic shock groups) between January 2020 to February 2021. Patients who are pregnant and ≤18 years old were excluded. Demographics, vital parameters, the presence of mechanical ventilation, and vasopressor/inotropic support with the doses of the drugs used were recorded. Ultrasonographic measurements included bedside caval indexes and left ventricular outflow tract (LVOT) peak velocity measurements. The primary outcome was in-hospital and 28th-day mortality.

Results

A total of 116 patients with a median age of 72.5 (27 to 96) years were enrolled. Sixty-eight (58.6%) patients were male. According to a receiver operating characteristic (ROC) curve analysis, 75 cm/s was determined as a cut-off value to determine the efficacy of LVOT peak velocity measurement for discriminating septic shock from sepsis and predicting 28-day and in-hospital mortality. The patients were then regrouped as 54 (46.5%) patients in low and 62 (53.5%) patients in high-velocity groups according to the cut-off value. Both in-hospital and 28th-day mortality rates were significantly different between these groups (p<0.001).

Conclusion

Left ventricular outflow tract peak velocity measurement may be a useful adjunct for the prediction of mortality in septic patients. Vasopressors and volume status of the patient do not affect LVOT peak velocity measurements.

Left Ventricular Outflow Tract Obstruction in Patients Treated With Milrinone for Cerebral Vasospasm: Case Report and Literature Review

Subarachnoid hemorrhage is associated with high morbidity and mortality, and cerebral arterial vasospasm is one of its main complications that determines neurological prognosis. The use of intravenous milrinone is becoming more common in the treatment of vasospasm. This molecule has positive inotropic and vasodilating properties by inhibiting phosphodiesterase-3. Its most described side effects are cardiac arrhythmias and arterial hypotension. In this paper, we raise a new issue concerning milrinone and discuss an undescribed side effect of this treatment, left ventricular outflow tract obstruction (LVOTO). Dynamic LVOTO is a clinical situation favored by hypovolemia, decreased left ventricular afterload, and excessive inotropism that can lead to severe hemodynamic failure and pulmonary edema. To our knowledge, this is the first study describing milrinone-induced LVOTO. This could compromise cerebral perfusion and therefore the neurological prognosis of patients. While it is known that catecholamines may induce LVOTO, milrinone-induced LVOTO appears to be a new pathophysiological entity of which neurosurgical intensivists should be aware.

Beta Blockers as Salvage Treatment in Refractory Septic Shock Complicated With Dynamic Left Ventricular Outflow Tract Obstruction: A Rare Case Presentation

Hypotension is the main finding in patients admitted to an intensive care unit (ICU) with the diagnosis of septic shock and it is related to worse outcomes. In these patients, several underlying causes of hypotension may co-exist, including vasoplegia, hypovolemia, drug-mediated venodilation, or myocardial dysfunction. Nowadays, echocardiography has been positioned as an essential tool in any ICU set to assess fluid status, ventricular ejection fraction, or any other myocardial complications. The high sympathetic tone in severely ill patients, in addition to high doses of adrenergic drugs often needed, may provoke a hypercontractile cardiac state. In the basis of our experience, we present a case of a patient with refractory septic shock and severe hemodynamic collapse, refractory to vasopressors with concomitant respiratory deterioration due to dynamic left ventricular outflow tract obstruction (LVOTO). Transesophageal echocardiography (TOE) was used to assess hemodynamic status and to guide treatment. A critical response to intravenous β-blockers was seen, with a dramatic decrease in vasopressor dosage and respiratory support.

Transient Systolic Anterior Motion of the Anterior Mitral Valve Leaflet in a Critical Care Patient with a Structurally Normal Heart

Systolic anterior motion (SAM) is defined as the displacement of the anterior mitral leaflet towards the left ventricular outflow tract, which results in left ventricular outflow tract obstruction (LVOTO). The SAM of the anterior mitral leaflet is a well-established phenomenon in hypertrophic obstructive cardiomyopathy (HOCM), but its occurrence in a structurally healthy heart is uncommon. We present a critical care patient with presumed septic shock whose blood pressure was previously controlled by fluid resuscitation and vasopressors. He developed a new cardiac murmur along with hypotension despite being on vasopressors. The echocardiographic assessment revealed no structural heart disease or valvular vegetations but a hyperdynamic left ventricle with significant SAM of the anterior mitral leaflet, resulting in mitral regurgitation (MR). The murmur and hypovolemia resolved after aggressive fluid resuscitation and by decreasing the vasopressor dose.

Left ventricular outflow tract obstruction in ICU patients

PURPOSE OF REVIEW

Left ventricular (LV) outflow tract (LVOT) obstruction (LVOTO) is not unusual in ICU patients particularly with septic shock.

RECENT FINDINGS

LVOT was first described in patients with hypertrophic cardiomyopathy and was defined as LV wall thickness at least 15 mm. LVOT is usually because of systolic anterior motion of the mitral valve. By convention, LVOTO is defined as an instantaneous peak Doppler LVOT pressure gradient at least 30 mmHg at rest or during physiological provocation such as Valsalva maneuver. Recently, it has been demonstrated that LVOT can be present in patients with severe hypovolemia or hyperkinesia with or without LV hypertrophy and can lead to hemodynamic compromise. LVOT is because of a combination of precipitating factors, which may or may not be associated with anatomical abnormalities. Decreased preload because of hypovolemia or decreased afterload because of septic shock, increased heart rate, and LV hyperkinesis produced by dobutamine infusion can induce a change of LV shape and induce LVOTO.

SUMMARY

LVOTO is not uncommon in ICU patients and can be observed at the early phase of septic shock. Treatment should include discontinuation of dobutamine infusion and fluid infusion. β blockers can be useful in this clinical situation.

Left ventricular outflow tract obstruction-be prepared!

The current trend to treat hypotension in critically ill patients is to place a greater emphasis on inotropic support and less on fluid resuscitation in order to limit the potential harm from fluid overload. This combination may trigger left ventricular outflow tract obstruction (LVOTO) in susceptible patients. Although LVOTO is classically described in patients with hypertrophic cardiomyopathy it has been reported in other conditions including septic shock, apical ballooning syndrome, myocardial infarction, respiratory failure, and post valvular surgery. It is more common in the elderly, females, and in patients with hypertension, diabetes, and chronic vascular disease because of predisposing anatomical conditions such as left ventricular hypertrophy, small left ventricle size, sigmoid septum and alterations in the positions of the aortic and mitral valve annular planes. The onset of LVOTO is largely unpredictable due to a complex interplay between preload, afterload, heart rhythm and rate in susceptible patients. The consequences of missing this treatable condition may lead to life-threatening hypotension refractory to, or exacerbated by, a further increase in inotropic support. Dynamic LVOTO should be considered in any hypotensive intensive care patient. Echocardiography is perhaps the best tool to assess LVOTO and its underlying pathophysiology in the critically ill. Detection of LVOTO is a relatively simple task using a combination of two-dimensional, M-mode and spectral Doppler imaging by an operator alert to the possible diagnosis.

Hemodynamic and metabolic characteristics associated with development of a right ventricular outflow tract pressure gradient during upright exercise

Background

We recently reported a novel observation that many patients with equal resting supine right ventricular(RV) and pulmonary artery(PA) systolic pressures develop an RV outflow tract(RVOT) pressure gradient during upright exercise. The current work details the characteristics of patients who develop such an RVOT gradient.

Methods

We studied 294 patients (59.7±15.5 years-old, 49% male) referred for clinical invasive cardiopulmonary exercise testing, who did not have a resting RVOT pressure gradient defined by the simultaneously measured peak-to-peak difference between RV and PA systolic pressures.

Results

The magnitude of RVOT gradient did not correspond to clinical or hemodynamic findings suggestive of right heart failure; rather, higher gradients were associated with favorable exercise findings. The presence of a high peak RVOT gradient (90^th percentile, ≥33mmHg) was associated with male sex (70 vs. 46%, p = 0.01), younger age (43.6±17.7 vs. 61.8±13.9 years, p<0.001), lower peak right atrial pressure (5 [3–7] vs. 8 [4–12]mmHg, p<0.001), higher peak heart rate (159±19 vs. 124±26 beats per minute, p<0.001), and higher peak cardiac index (8.3±2.3 vs. 5.7±1.9 L/min/m², p<0.001). These associations persisted when treating peak RVOT as a continuous variable and after age and sex adjustment. At peak exercise, patients with a high exercise RVOT gradient had both higher RV systolic pressure (78±11 vs. 66±17 mmHg, p<0.001) and lower PA systolic pressure (34±8 vs. 50±19 mmHg, p<0.001).

Conclusions

Development of a systolic RV-PA pressure gradient during upright exercise is not associated with an adverse hemodynamic exercise response and may represent a normal physiologic finding in aerobically fit young people.

Early dynamic left intraventricular obstruction is associated with hypovolemia and high mortality in septic shock patients

Introduction

Based on previously published case reports demonstrating dynamic left intraventricular obstruction (IVO) triggered by hypovolemia or catecholamines, this study aimed to establish: (1) IVO occurrence in septic shock patients; (2) correlation between the intraventricular gradient and volume status and fluid responsiveness; and (3) mortality rate.

Method

We prospectively analyzed patients with septic shock admitted to a general ICU over a 28-month period who presented Doppler signs of IVO. Clinical characteristics and hemodynamic parameters as well as echocardiographic data regarding left ventricular function, size, and calculated mass, and left ventricular outflow Doppler pattern and velocity before and after fluid infusions were recorded.

Results

During the study period, 218 patients with septic shock were admitted to our ICU. IVO was observed in 47 (22 %) patients. Mortality rate at 28 days was found to be higher in patients with than in patients without IVO (55 % versus 33 %, p < 0.01). Small, hypercontractile left ventricles (end-diastolic left ventricular surface 4.7 ± 2.1 cm²/m² and ejection fraction 82 ± 12 %), and frequent pseudohypertrophy were found in these patients. A rise ≥12 % in stroke index was found in 87 % of patients with IVO, with a drop of 47 % in IVO after fluid infusion.

Conclusion

Left IVO is a frequent event in septic shock patients with an important correlation with fluid responsiveness. The mortality rate was found to be higher in these patients in comparison with patients without obstruction.

Bedside clinical and ultrasound-based approaches to the management of hemodynamic instability--part I: focus on the clinical approach: continuing professional development

Shock is defined as a situation where oxygen transport is inadequate to meet the body's oxygen demand. An understanding of the mechanism(s) of reduced cardiac output, a determinant of oxygen transport, is crucial in order to initiate appropriate therapy to manage shock. Combining the concept of venous return with the ventricular pressure-volume relationship is a useful method to appreciate the complex circulatory physiology of shock. Clues from the patient's history, physical examination, and key laboratory tests, along with the careful inspection of hemodynamic, electrocardiographic and respiratory waveforms can help with the identification of the etiology and mechanism(s) of shock. Following verification of the arterial pressure, general resuscitation can begin, and more specific treatment can be undertaken to manage shock. If the patient is unresponsive to these measures, bedside ultrasound can then be performed to ascertain more detail regarding the mechanism(s) and etiology of shock.

PURPOSE

To develop an approach to the management of the hemodynamically unstable patient.

PRINCIPAL FINDING

Not applicable.

CONCLUSION

Not applicable.

Unexpected refractory intra-operative hypotension during non-cardiac surgery: Diagnosis and management guided by trans-oesophageal echocardiography

We present a case of severe refractory hypotension in a patient undergoing de-bulking liver resection for massive polycystic liver disease. Emergent trans-oesophageal echocardiography (TOE) revealed dynamic left ventricular outflow tract (LVOT) obstruction with systolic anterior motion (SAM) of the anterior mitral leaflet (AML). Notably, he had a structurally normal heart on pre-operative trans-thoracic echocardiography (TTE). Diagnosis of SAM by TOE, possible mechanisms and specific management of refractory hypotension in this context are discussed.

Paradoxical heart failure precipitated by profound dehydration: intraventricular dynamic obstruction and significant mitral regurgitation in a volume-depleted heart

Occurrence of dynamic left ventricular outflow tract (LVOT) obstruction is not infrequent in critically ill patients, and it is associated with potential danger. Here, we report a case of transient heart failure with hemodynamic deterioration paradoxically induced by extreme dehydration. This article describes clinical features of the patient and echocardiographic findings of dynamic LVOT obstruction and significant mitral regurgitation caused by systolic anterior motion of the mitral valve in a volume-depleted heart.

Left ventricular outflow tract obstruction with systolic anterior motion of the mitral valve in patient with pericardial effusion caused by ascending aortic dissection -A case report-

Left ventricular outflow tract (LVOT) obstruction with systolic anterior motion (SAM) of mitral valve is not only limited to patients with hypertrophic cardiomyopathy. A diagnosis of LVOT obstruction with SAM is important because conventional inotropic support may potentially aggravate hemodynamic deterioration. We present a case of LVOT obstruction with SAM in a patient who underwent an emergent surgery for ascending aortic dissection with pericardial effusion. The patient showed refractory hypotension after standard pharmacologic interventions during induction of anesthesia. Transesophageal echocardiography (TEE) revealed LVOT obstruction with SAM and it was managed appropriately under the guidance of TEE. Intraoperative TEE can play an important role in diagnosis and management of LVOT obstruction with SAM caused by pericardial effusion.

[Dynamic left ventricular outflow tract obstruction in pulmonary embolism]

Left ventricular hypertrophy, dehydration, sepsis, vasodilatation, excessive sympathetic stimulation, pericardial tamponade and surgical treatment of the atrioventricular valve are known causes of left ventricular outflow tract (LVOT) obstruction. We report the rare case of a patient who developed dynamic LVOT obstruction as a complication of acute pulmonary embolism.

Pathophysiology of dynamic left ventricular outflow tract obstruction in a critically ill patient

Left ventricular outflow tract obstruction is not a rare problem in the intensive care units and can precipitate hemodynamic shock unresponsive to catecholamine therapy. The use of echocardiographic examination is extremely important in recognizing this phenomenon and its underlying conditions, finally identifying the most appropriate therapeutic strategy. The simple correction of one or more of these factors can dramatically change patients clinical outcome. We report the clinical case of a 72-year-old man who developed hemodynamic shock in the intensive care unit. Hypovolemia, catecholamine infusion, and mechanical ventilation induced geometric modification of the left ventricle causing a systolic anterior motion of the mitral anterior leaflet and a severe subaortic gradient. Simple restoration of fluids and discontinuation of medical therapy dramatically changed the outcome of the patient. A review of the medical literature has been carried out to deeply investigate pathophysiology of left ventricular outflow tract obstruction in critically ill patients.

Dynamic left ventricular outflow tract obstruction in living donor liver transplantation recipients -A report of two cases-

We present two cases of dynamic left ventricular outflow tract obstruction in 2 patients who were undergoing living donor liver transplantation. On the preoperative transthoracic echocardiography, the first patient showed normal ventricular function and a normal wall thickness, but severe hemodynamic deterioration developed during the anhepatic period and this was further aggravated after reperfusion in spite of volume resuscitation and catecholamine therapy. Intraoperative transesophageal echocardiography revealed the systolic anterior motion of the mitral valve leaflet together with left ventricular outflow tract obstruction. The second patient showed left ventricular hypertrophy with left ventricular outflow tract obstruction on the preoperative echocardiography. Intraoperative transesophageal echocardiography was used to guide fluid administration and the hemodynamic management throughout the procedure and a temporary portocaval shunt was established to mitigate the venous pooling during the anhepatic period. The purpose of this report is to emphasize the clinical significance of dynamic left ventricular outflow tract obstruction in patients who are undergoing living donor liver transplantation and the role of intraoperative echocardiography to detect and manage it.

Comparison of auscultatory and echocardiographic findings in healthy adult cats

OBJECTIVES

This pilot study was performed to investigate murmur prevalence and to explore the association between auscultatory and echocardiographic findings in apparently healthy cats in order to design a larger study.

ANIMALS, MATERIALS AND METHODS

Adult cats in 4 rehoming centres were screened by auscultation and echocardiography (echo) over 2 periods of 2 weeks each. In the first period, echo was attempted only in cats with murmurs. In the second period, all cats underwent auscultation by 2 observers and echo. LVH was defined in 5 ways: maximal diastolic left ventricular (LV) wall thickness ≥ 6 mm or ≥ 5.5 mm with 2D (LVH(6 2D), LVH(5.5 2D), respectively) or M-Mode echo (LVH(6 MM) or LVH(5.5 MM) respectively), or LV wall thickness ≥ 6 mm (2D) for >50% of a wall segment (LVH(50%)).

RESULTS

67/199 (34%) cats had a murmur. Interobserver agreement on murmur presence was moderate (κ 0.47). 61 cats with a murmur and 31 cats without underwent both auscultation and echo. Depending on the criteria, LVH was present in 31 (LVH(6 2D)), 21 (LVH(50%)) and 11 (LVH(6 MM)) scanned cats. 18-62% of cats with murmurs had LVH, depending on the echo criteria used. Agreement was best between observers in identifying LVH using LVH(6 2D) and LVH(50%) (κ = 1.0).

CONCLUSIONS

Heart murmurs are common in apparently healthy cats. The prevalence of LVH varies depending on the criteria used.

Cerebral vasospasm and concurrent left ventricular outflow tract obstruction: requirement for modification of hyperdynamic therapy regimen

BACKGROUND

Medical treatment of arterial vasospasm following aneurysmal subarachnoid hemorrhage (SAH) generally consists of triple H therapy, which frequently relies on inotropic agents in order to increase cardiac output (CO). Patients with concurrent left ventricular outflow tract (LVOT) obstruction may have paradoxical decreases in CO following administration of inotropic pressors, placing them at significant risk for cerebral ischemia and stroke.

METHODS

The clinical courses of two patients with SAH-induced arterial vasospasm and underlying left ventricular outflow obstruction are reported. Both patients had hypotension and low cardiac output that were refractory to medical management with triple H therapy. Echocardiography in both patients demonstrated LVOT obstruction secondary to hypertrophic obstructive cardiomyopathy (HOCM).

RESULTS

Intervention in both patients included discontinuation of inotropic agents and maintenance of hypervolemia to a target pulmonary capillary wedge pressure range, resulting in improved cardiac output and mean arterial pressure.

CONCLUSION

Medical treatment for cerebral vasospasm with inotropic pressor agents may result in paradoxical decreases in hemodynamic parameters and cerebral perfusion in patients with LVOT obstruction. While HOCM is the most likely structural abnormality to cause this phenomenon, it can be induced by several physiological conditions encountered in the neurocritical care setting. Modifications in triple H therapy regimens may be required in order to optimize cerebral perfusion and prevent cerebral ischemia and stroke in these patients.

Standing position alone or in combination with exercise as a stress test to provoke left ventricular outflow tract gradient in hypertrophic cardiomyopathy and other conditions

Measuring left ventricular outflow tract (LVOT) gradient by echocardiography in decubitus position, which is used in routine clinical practice, does not reflect the pathophysiology of this dynamic abnormality during daily activities, which trigger the symptoms. LVOT obstruction is dynamic and greatly dependent upon the left ventricular cavity size, geometric configuration of hypertrophy, load, contractility and mitral apparatus abnormalities, including systolic anterior motion of mitral leaflet. Importantly, LVOT gradient may develop not only in hypertrophic cardiomyopathy, but also in other heart diseases. Recent studies show that LVOT gradient should be measured both in a standing position and during exercise.

Dobutamine stress echocardiography unmasks acute worsening of mitral regurgitation with latent left ventricular outflow tract obstruction behind diastolic heart failure in hypertensive heart disease

In a 57-year-old woman who was referred as refractory diastolic heart failure, dobutamine stress echocardiography facilitated the diagnosis of acute worsening of mitral regurgitation accompanied with latent left ventricular outflow tract obstruction as a cause of recurrent flash pulmonary edema. Echocardiography revealed the presence of sigmoid septum and concentric left ventricular hypertrophy, being consistent with hypertensive heart disease. Dobutamine induced systolic anterior motion of the mitral valve (SAM) with massive mitral regurgitation, resulting in sudden hypotension with dyspnea. The class Ia antiarrhythmic drug, cibenzoline, reduced the SAM during a dobutamine stress test, followed by no recurrence of flash pulmonary edema.

Mechanism and correlated factors of SAM phenomenon after aortic valve replacement

To investigate the mechanism and correlated factors of systolic anterior motion (SAM) phenomenon after aortic valve replacement, 48 patients with severe aortic valvular stenosis were studied. Tested by echo-Doppler one week after aortic valve replacement, the patients were divided into two groups: SAM group and non-SAM group. The data of the left ventricular end-diastolic diameters, the left ventricular end-systolic diameters, the left ventricular outflow diameters, the thickness of the interventricular septum, the posterior wall of left ventricle, the blood velocities of left ventricular outflow and intra-cavitary gradients were recorded and compared. The results showed that no patients died during or after the operation. The blood velocities of left ventricular outflow was increased significantly in 9 patients (>2.5 m/s), and 6 of them developed SAM phenomenon. There was significant difference in all indexes (P<0.05 or P<0.01) except the posterior wall of left ventricle (P>0.05) between two groups. These indicated that the present of SAM phenomenon after aortic valve replacement may be directly related to the increase of blood velocities of left ventricular outflow and intra-cavitary gradients. It is also suggested that smaller left ventricular diastolic diameters, left ventricular systolic diameters, left ventricular outflow diameters and hypertrophy of interventricular septum may be the anatomy basis of SAM phenomenon.

Transient dynamic subaortic stenosis in premature neonates after patent ductus arteriosus ligation

We describe 2 premature infants with PDA that did not respond to medical therapy and required surgical ligation. Both infants developed transient dynamic subaortic obstruction that resolved without specific therapy. This may have occurred due to sudden changes in the left ventricular volume.

Dynamic left ventricular outflow tract obstruction without basal septal hypertrophy, caused by catecholamine therapy and volume depletion

Hypertrophic cardiomyopathy (HCM) with hypertrophy of the basal septum is the most common etiology of left ventricular outflow tract (LVOT) obstruction. In this article, we report the case of a patient with a structurally normal heart who developed hemodynamic deterioration due to severe LVOT obstruction following treatment with catecholamines. Hypovolemia accompanied with a hyperdynamic condition, resulting from catecholamine treatment, may cause dynamic LVOT obstruction due to the systolic anterior motion of the mitral valve leaflet. The solution for this is early recognition and correction of aggravating factors such as, withdrawal of catecholamine therapy and volume replacement.

Importance of transesophageal echocardiography in the critically ill and injured patient

Echocardiography, particularly transesophageal echocardiography (TEE), is a vital diagnostic and monitoring imaging modality for the intensivist. The field of echocardiography spans different venues and pathologies, ranging from surface transthoracic echocardiography and portable hand-held echocardiography, to contrast echocardiography, stress echocardiography, and TEE, among others. Numerous investigations have proven the worth of echocardiography, especially TEE, in the critically ill and injured patient, changing lives with the identification of obvious and subtle cardiothoracic diseases. Because this powerful imaging tool is immediately available and portable, crucial delays in diagnosis are not commonplace; rather than echocardiography, TEE, specifically, should be (and is in some institutions) the standard of care and management in assisting the intensivist in diagnosis of a variety of maladies. The effect of TEE technology is quite formidable, and numerous investigations have borne this out. The therapeutic effect of TEE ranges from 10% to 69%, with the majority of investigations falling into the 60% to 65% range. The diagnostic yield of TEE is far greater, approaching 78%. This article will detail the importance of echocardiography, its efficacy, and its high-yield imaging capability, particularly when compared with other imaging modalities, even transthoracic echocardiography.