Epicardial left ventricular lead placement for cardiac resynchronization therapy: optimal pace site selection with pressure-volume loops.

OBJECTIVES: Patients in heart failure with left bundle branch block benefit from cardiac resynchronization therapy. Usually the left ventricular pacing lead is placed by coronary sinus catheterization; however, this procedure is not always successful, and patients may be referred for surgical epicardial lead placement. The objective of this study was to develop a method to guide epicardial lead placement in cardiac resynchronization therapy. METHODS: Eleven patients in heart failure who were eligible for cardiac resynchronization therapy were referred for surgery because of failed coronary sinus left ventricular lead implantation. Minithoracotomy or thoracoscopy was performed, and a temporary epicardial electrode was used for biventricular pacing at various sites on the left ventricle. Pressure-volume loops with the conductance catheter were used to select the best site for each individual patient. RESULTS: Relative to the baseline situation, biventricular pacing with an optimal left ventricular lead position significantly increased stroke volume (+39%, P =.01), maximal left ventricular pressure derivative (+20%, P =.02), ejection fraction (+30%, P =.007), and stroke work (+66%, P =.006) and reduced end-systolic volume (-6%, P =.04). In contrast, biventricular pacing at a suboptimal site did not significantly change left ventricular function and even worsened it in some cases. CONCLUSIONS: To optimize cardiac resynchronization therapy with epicardial leads, mapping to determine the best pace site is a prerequisite. Pressure-volume loops offer real-time guidance for targeting epicardial lead placement during minimal invasive surgery.

Right ventricular support for off-pump coronary artery bypass grafting studied with bi-ventricular pressure--volume loops in sheep.

OBJECTIVES: Tilting the heart during off-pump coronary artery bypass grafting (OPCABG) causes a strong decrease in cardiac output. It is hypothesized that this decrease is caused by reduced right ventricular filling and that right ventricular support is thus the best way to restore cardiac output. Simultaneous left and right ventricular pressure-volume loops were used to test this hypothesis. METHODS: In seven sheep, the heart was tilted with the use of an Octopus device. After unsupported tilting, a novel right ventricular support, the Enabler, was activated at a pulsatile flow of 1.6 l/min. Pressure-volume loops of both ventricles were obtained using conductance catheters, and cardiac output was monitored with an aortic flow probe. RESULTS: Tilting reduced cardiac output by 31% (4.4--3.1 l/min, P=0.001) and right ventricular end-diastolic volume by 44% (86--51 ml, P=0.005), while right ventricular end-diastolic pressure did not decrease. Left ventricular systolic pressure was not significantly reduced upon tilting and even increased in two animals. During Enabler right ventricular support, the cardiac output remained 23% lower than pre-tilting values (3.4 vs. 4.4 l/min, P=0.001). CONCLUSIONS: Restricted right ventricular filling is the primary cause of the strong decrease in cardiac output during tilting. The Enabler right ventricular support can currently not restore cardiac output to pre-tilting values, mainly caused by its limited output and a decrease in right ventricular output upon Enabler activation. Constant monitoring of cardiac output is crucial during (unsupported or supported) tilting as blood pressure alone may not reflect the extent of the reduction in cardiac function.

Ruptured aneurysm of the left sinus of Valsalva into the pericardium.

Recently, a 67-year-old female patient came to our attention after a collapse, due to cardiac tamponade caused by a ruptured sinus of Valsalva aneurysm (SVA) and intrapericardial bleeding. Despite surgical intervention the patient died before correction.

The enabler right ventricular circulatory support system for beating heart coronary artery bypass graft surgery.

BACKGROUND: Beating heart coronary artery bypass graft surgery of the left anterior descending, diagonal, and right coronary artery can be performed safely with the Octopus Stabilization System. However, tilting of the heart, which is necessary to reach the obtuse marginal and distal right coronary arteries, causes hemodynamic instability. This study was performed to investigate the possible role of the Enabler right ventricular circulatory support system in counteracting this instability. METHODS: In 8 sheep, the Enabler cannula was introduced via the jugular vein and positioned with the inlet valve in the right atrium and outlet valve in the pulmonary artery. The Octopus was used to expose the inferior wall and the posterior wall of the left ventricle. The hemodynamic effects of this tilting with and without Enabler right ventricular support were recorded, including Pressure Volume (PV) loops measured by conductance catheters in both ventricles. RESULTS: Tilting caused a reduction in stroke volume (inferior 31%, posterior 17%) and Enabler activation increased stroke volume (inferior 13%, posterior 31%). CONCLUSIONS: Tilting the heart has severe hemodynamic consequences that can be partially counteracted by the use of the Enabler for right ventricle support.

Comparison of arterial wall reaction after passage of the Hydrolyser device versus a thrombectomy balloon in an animal model.

PURPOSE: This study was designed to compare the reaction of the vessel wall after application of the Hydrolyser hydrodynamic thrombectomy device to the reaction after use of a balloon thrombectomy catheter. The influence of the vessel inner diameter on vessel wall reaction was evaluated after passage of the Hydrolyser. MATERIALS AND METHODS: After measurement of the vessel inner diameter with intravascular ultrasound (US), 102 segments of femoral and carotid arteries of goats were treated with one of the following four procedures: passage of the intravascular US catheter alone; passage of the Hydrolyser without or with an activated jet; or passage of an inflated thrombectomy balloon. Histologic evaluation was performed after 3 weeks. RESULTS: Intimal thickening (more than five cell layers of neointima) 3 weeks after treatment occurred more frequently after passage of the balloon than after any of the other procedures (P < .001). For vessels with a diameter of 3-4 mm, 4-5mm, or more than 5 mm, no significant difference in vessel wall reaction was observed following Hydrolyser passage. CONCLUSION: In this model, passage of the Hydrolyser device resulted in less intimal reaction compared with the thrombectomy balloon.

Giant intrapericardial aneurysm of the left atrial appendage.

A young patient is reported with an aneurysm of the left atrial appendage having supraventricular arrhythmias and a period of chest pain accompanied by a rise in cardiac enzymes. Compression of the left anterior descending coronary artery by the aneurysm was felt to be responsible for the myocardial injury.