Surgical ventricular reconstruction and subendocardial resection for the treatment of refractory ventricular tachycardia

We describe a case of 64-year-old female patient with ventricular tachycardia intractable to medical treatment and acute heart failure following myocardial infarction. Emergency surgical ventricular reconstruction and subendocardial resection was undertaken. We discuss the option of surgical intervention in this difficult and unusual clinical scenario.     

Experimental acute right ventricular failure and right ventricular assist in the dog

We describe a technique for the production of acute progressive right ventricular failure in experimental animals that mimics the hemodynamic characteristics of right ventricular failure found in some patients being weaned from extracorporeal circulation after surgical repair of left ventricular abnormalities. The technique combines three alterations of right ventricular state: excision of the tricuspid valve, ventriculotomy, and ligation of the right coronary artery. Seven control dogs died within 3 hours after this intervention. Death was due to low cardiac output as a result of low left atrial and pulmonary arterial pressures. Right atrial pressure was high. Use of a right ventricular assist device in an additional seven dogs to pump blood from the right atrium to the pulmonary artery confirmed good preservation of left ventricular function by reestablishing adequate left ventricular filling pressure. All seven dogs survived for more than 3 hours. The validity of the technique in restricting failure principally to the right ventricle was thus demonstrated.     

Late potentials, ventricular stimulation and ventricular tachycardia

Late potentials are depolarizations which arise from areas of delayed ventricular activation and may indicate a propensity for ventricular tachycardia. Sixty-four subjects were assessed by non-invasive measurement. Late potentials were not present in 20 subjects with normal hearts nor in 6 patients with cardiac disease but with no evidence of ventricular tachycardia (VT). Seventeen of 20 patients with recurrent sustained ventricular tachycardia (RSVT) and 2 of 10 patients with unsustained VT had late potentials. None of the 6 patients with automatic VT or the 2 patients with torsades de pointe had late potentials. In a subgroup of 28 symptomatic patients in whom programmed ventricular stimulation was performed, late potentials correlated with inducibility of sustained VT (P less than 0.05). Late potentials may therefore serve as a useful marker of RSVT and confirm a re-entrant mechanism of VT.     

Effects of the left ventricular assist device on right ventricular function

Right ventricular failure is a leading cause of death in patients who require the left ventricular assist device. Previous reports suggested right ventricular functional deterioration during left ventricular assist but lacked a method by which right ventricular function could be quantified adequately. This study examined the effects of left ventricular volume unloading on right ventricular systolic function by means of the stroke work/end-diastolic volume relationship, a load-insensitive index of myocardial performance. In 12 anesthetized open-chested dogs, right ventricular and left ventricular pressures were measured with micromanometers while ultrasonic dimension transducers measured left and right ventricular orthogonal diameters. Left ventricular unloading was accomplished with left atrial-to-femoral artery bypass with a centrifugal pump. Data were recorded during transient vena caval occlusion in the control state and with maximal left ventricular unloading by full support by the left ventricular assist device. Modified ellipsoidal geometry was used to calculate simultaneous biventricular volumes, and linear regression analysis of right ventricular stroke work versus end-diastolic volume was used to quantify right ventricular systolic function. Average slope and x intercept of this relationship under control conditions were 2.2 +/- 0.3 X 10(4) erg/ml and 10.7 +/- 5.0 ml, respectively. During full support by the left ventricular assist device (mean flow rate, 2.4 +/- 0.3 L/min), left ventricular end-diastolic volume decreased by 31% (p less than 0.01), left ventricular septal-free wall diameter decreased by 7% (p less than 0.001), and rate of rise of right ventricular peak positive pressure declined by 13% (p less than 0.05). The corresponding slope and x intercept of the right ventricular stroke work/end-diastolic volume relationship during full unloading of left ventricular assist device were 2.3 +/- 0.3 X 0.3 X 10(4) erg/ml and 14.3 +/- 4.8 ml, respectively; these values were not significantly different from control values (p greater than 0.5). Additionally, analysis of right ventricular end-diastolic pressure-volume relationships suggested improved right ventricular chamber compliance, although the effects were small and did not reach statistical significance (p = 0.10). These data imply that marked alterations in biventricular geometry accompanying left ventricular volume unloading by the left ventricular assist device in a normal heart do not significantly alter right ventricular performance characteristics.     

Left ventricular diverticulum with hypertrophy of the left ventricular apex.

A surgical case of diverticulum in the left ventricular apex is presented. A two-dimensional echocardiogram and magnetic resonance image showed a calcified tumor buried in the marked hypertrophied apex of the left ventricle. Enucleation of the oval and hard tumor (4 x 2.5 x 2.5 cm) was performed through the apex, and the defect was anastomosed by buttress sutures. Histologic examination demonstrated that the tumor cavity was filled with a thrombus encapsulated by thickened and calcified endocardium that extended to the left ventricular cavity. In this report, the etiology of the diverticulum with a hypertrophied myocardium is discussed.     

Left ventricular performance after patch reconstruction of the left ventricular wall for postinfarction left ventricular aneurysms]

Left ventricular performance in patients with a left ventricular aneurysm (LVA) treated with patch reconstruction is largely unknown. This study consisted of 15 patients, 14 men and 1 woman, with the average age of 59 +/- 8.5 years. The resected area of LVA was 40 +/- 27 cm2. The area of the woven Dacron patch used for reconstruction was 57 +/- 19% of the resected area including the sewing rim. The EF (Ejection Fraction, 1/3FF (Filling Fraction) and PFR (Peak Filling Rate) were calculated by 99mTc equilibrium cardiac pool scintigraphic images. The A/R ratio (peak velocity during atrial kick phase/peak velocity during the rapid filling phase) was measured using Doppler echocardiography, at the mitral orifice level. These parameters were determined before and 1 to 2 months after the operation. The time course was followed for A/R ratios. The preoperative resting global EF was 0.28 +/- 0.14 (0.44 +/- 0.13 for the contractile area) and the EF during exercise was 0.31 +/- 0.14. Resting and exercise EFs improved significantly (p < 0.01) to 0.40 +/- 0.11 and 0.43 +/- 0.10 postoperatively. The 1/3FF (%) and PFR (/sec) were low before operation (1/3FF, 11.3 +/- 8.3; PFR, 1.2 +/- 0.47). Postoperatively, the 1/3FF rose to 14.8 +/- 9.3 and the PFR showed a significant (p < 0.05) increase to 1.6 +/- 0.6. The A/R ratio significantly (p < 0.05) improved from preoperative 1.76 +/- 0.46 to 0.95 +/- 0.11 on the 3rd postoperative day. This improvement was maintained until the late postoperative period, with a value of 1.14 +/- 0.29 at month 16.(ABSTRACT TRUNCATED AT 250 WORDS)     

Aneurysm of the membranous ventricular septum with ventricular septal defect, mitral and tricuspid insufficiency

A seventy-year-old man was admitted at our hospital because of dyspnea. Echocardiogram and left ventriculogram showed an aneurysm formation of the membranous ventricular septum and small left-to-right shunt through ventricular septum defect and also severe mitral and tricuspid insufficiency. Operation was performed after medical therapy for congestive heart failure. During operation, mitral leaflets showed no organic lesions nor prolapse, but the annulus was dilated. The cause of mitral insufficiency, we thought, might be congenital, and the annulus dilatation was caused to produce tricuspid insufficiency secondary. The ventricular septal communication became small (diameter; 5 mm) and was associated with aneurysm formation of the remaining portion of the membranous septum. And the aneurysm, protruding to the septal leaflet of tricuspid valves, enhanced tricuspid insufficiency. It was reported by many authors that the aneurysm formation was related to spontaneous closure of ventricular septal defect. Patients with small ventricular septal defect, without any symptoms, must be followed intensively, or they might get cardiac complications, such as arrhythmia, right ventricular outflow obstruction, tricuspid insufficiency, and so on.     

Repair of transposition of the great arteries with intact ventricular septum and left ventricular outflow tract obstruction

Repair of transposition of the great arteries in patients with intact ventricular septum and fixed left ventricular outflow tract obstruction has been restricted to atrial baffle procedures, with or without attempts to relieve or bypass the left ventricular outflow obstruction. However, the suboptimal results of these procedures, coupled with excellent functional results with the arterial switch operation in patients without obstruction, has made anatomic correction the goal in repairing these anomalies. We report a technique for the anatomic correction of transposition of the great arteries, intact ventricular septum, and fixed left ventricular outflow tract obstruction. Its consideration in these difficult cases is advocated.     

Impact of biventricular and left ventricular pacing on hemodynamics and left ventricular dyssynchrony compared with right ventricular pacing in the early postoperative period following cardiac surgery

Objectives

The aims of this study were to test the hypotheses that in the postoperative period following corrective surgery for congenital heart defects: (i) atrio-right ventricular (RA-RV) pacing decreases cardiac output (CO) compared with right atrial (RA) pacing, (ii) atrio-biventricular (RA-BiV) and left ventricular (RA-LV) pacing improves CO compared with RA-RV pacing.

Study design

Prospective observational study.

Patients

Children 0-2 years of age referred for surgery of congenital heart defects were studied during intrinsic rhythm and atrial, atrio-right ventricular, atrio-left ventricular and atrio-biventricular pacing. CO, extrapolated from mean systolic aortic velocity (MSAV), and left ventricular dyssynchrony were assessed using transthoracic echocardiography.

Results

RA-RV pacing induced a significant decrease in CO (MSAV 0.52 ± 0.19 m/s to 0.46 ± 0.16 m/s, p = 0.01) and a significant increase in LV dyssynchrony (8.7 ± 7.9 ms to 33 ± 21 ms, p = 0.001). RA-BiV pacing induced a significant increase in CO (MSAV 0.46 ± 0.16 m/s to 0.52 ± 0.18 m/s, p = 0.01) and a significant decrease in LV dyssynchrony (33 ± 21 ms to 7 ± 4 ms, p = 0.0003) compared with RA-RV pacing. RA-LV pacing induced a significant decrease in LV dyssynchrony (33 ± 21 ms to 9 ± 7 ms, p = 0.0007) without a significant improvement of CO compared with RA-RV pacing.

Conclusions

RA-BiV pacing improves CO compared with RA-RV pacing in the early postoperative period following pediatric cardiac surgery. This improvement is related to a reduction in left ventricular dyssynchrony.     

An improved technique for the closure of ventricular septal defect in ventricular inversion

An improved technique for the closure of ventricular septal defect associated with ventricular inversion through the anatomically left ventricle is described. The technique consists of placing a patch completely on the anatomically right ventricular side with modified horizontal mattress sutures all around the defect. This technique was applied successfully in 2 patients with no ensuing conduction disturbance. The details of the technique are reported.     

Effects of acute left ventricular unloading on right ventricular function in normal and chronic right ventricular pressure-overloaded lambs

OBJECTIVE: Right ventricular pressure overload occurs in several types of (congenital) heart disease, as well as in pulmonary disease. Clinical outcome in some of these patient groups might in part be related to left ventricular loading conditions. The effects of left ventricular unloading on the function of the hypertrophic right ventricle have not been studied. We aimed to study the effects of left ventricular unloading on right ventricular hemodynamics and contractility in an animal model of chronic right ventricular pressure overload. METHODS: In lambs the pulmonary artery was chronically banded to increase right ventricular pressure to systemic levels. After 8 weeks, right ventricular contractility and hemodynamic function were assessed in these lambs, as well as in age-matched control animals, by using a combined pressure-conductance catheter in the right ventricle during baseline conditions and during complete bypass of the left ventricle. RESULTS: In both groups acute left ventricular unloading significantly decreased left ventricular pressure to low levels while aortic pressure was maintained. In the right ventricle of the control group, both end-systolic and end-diastolic volumes increased with left ventricular unloading (P <.01) while end-systolic pressure was maintained. Cardiac output was unchanged despite decreased right ventricular contractility. In the banding group acute left ventricular unloading also decreased right ventricular contractility but increased cardiac output. During acute left ventricular unloading, diastolic stiffness was unchanged in the control group, whereas it was significantly decreased in the banding group. CONCLUSIONS: Both in normal hearts and in hearts subject to chronic right ventricular pressure overload, acute left ventricular unloading decreases right ventricular contractility. Although no effects on cardiac output are encountered in normal hearts during left ventricular bypass, cardiac output is improved in right ventricular pressure-overloaded hearts, most likely related to improved right ventricular diastolic compliance.     

Facile left ventricular deairing by administration of cardioplegia into the left ventricular vent

De-airing of left heart structures during minimally invasive valve operations is often difficult. A method of using a left ventricular vent temporarily hooked to the cardioplegia cannula for facile left ventricular deairing is described. Routine use of this simple method coupled with transesophageal echocardiography monitoring simplifies the process of left ventricular deairing in minimally invasive or standard valvular operations.     

Echocardiographic assessment of left ventricular function in left ventricular volume load and the immediate changes after operation

Cardiac function and changes following surgery was studied with computerized M-mode echocardiography in 12 patients with volume load of the left ventricle. Half of them had congenital lesions, the other half aortic regurgitation. Left ventricular (LV) shortening fraction and LV ejection time were significantly reduced postoperatively and came close to normal mean values. Also cardiac output and LV diameters normalized or at least started its normalization. The computerized values for rates of decrease and increase of left ventricular diameter were reduced postoperatively (p less than 0.01 and p less than 0.05 respectively) compared to elevated preoperative values. The study shows that relief of volume load on the left ventricle immediately leads to normalization of left ventricular function, especially if the myocardium was intact preoperatively.