Angiotensin converting enzyme (ACE) gene expression in the human left ventricle: effect of ACE gene insertion/deletion polymorphism and left ventricular function.

AIMS: We investigated the effect of the angiotensin converting enzyme (ACE) I/D polymorphism and left ventricular (LV) function on ACE gene expression in tru-cut LV myocardial biopsies from 50 consecutive patients (II: 18, ID: 18, DD: 14; 40 males) with ischaemic heart disease undergoing coronary artery bypass grafting (CABG). METHODS: The polymerase chain reaction was used for ACE genotyping. LV function [normal (n=22) or impaired] was determined by left ventriculography at cardiac catheterisation prior to bypass surgery. ACE expression was determined (n=46) by a competitive quantitative reverse transcription PCR assay using 5x10(5), 12. 5x10(5) and 20x10(5) copies of a mutant DNA internal standard (IS). PCR products were analysed by negative film photography and laser densitometry to determine the number of ACE transcripts present. RESULTS: Mean age was similar (II: 59.1+/-10.4, ID: 57.0+/-10.6, DD: 61.4+/-6.2; P=NS) with no differences between groups in sex (P=0. 25); hypertension, P=0.31; previous myocardial infarction, P=0.44; LV function, P=0.23; and ACE inhibitor therapy, P=0.06. ACE expression per 100 ng of total RNA varied with genotype [<5x10(5) copies in II: 6, 5-12.5x10(5) copies in II: 6, ID: 16, DD: 4; and >12.5x10(5) (II: 4, ID: 2, DD: 8), Kendall's tau-b coefficient (tau(b))=0.43, P=0.003]. Impaired LV function also correlated with higher levels of ACE expression, Kendall's tau(b)=0.40, P=0.001. CONCLUSION: ACE gene expression in the left ventricle varied with ACE genotype and LV function in IHD patients undergoing CABG.

Experimental model of left ventricular failure.

A model of chronic cardiac failure has undergone extensive hemodynamic investigation. Under anesthesia the homonymous and second diagonal coronary arteries of sheep have been ligated. The resulting myocardial infarction caused significant acute hemodynamic impairment (paired two-tailed t tests), mean pulmonary artery pressure increasing from 7.31 +/- 0.94 to 13.80 +/- 1.19 mm Hg (p less than 0.001), pulmonary artery diastolic pressure increasing from 4.94 +/- 1.03 to 11.13 +/- 1.27 mm Hg (p less than 0.001), and directly measured left ventricular end-diastolic pressure increasing from 9.31 +/- 1.52 to 17.42 +/- 1.82 mm Hg (p less than 0.001) after infarction documented with invasive monitoring. There was a hemodynamically significant left ventricular aneurysm (paired two-tailed t tests) in animals studied 3 months later, with increased mean pulmonary artery pressure from 7.20 +/- 1.15 to 13.80 +/- 2.00 mm Hg (p = 0.009), an increase in pulmonary artery diastolic pressure from 4.60 +/- 1.30 to 12.10 +/- 2.06 mm Hg (p = 0.006), and an increase in left ventricular end-diastolic pressure from 11.00 +/- 1.94 mm Hg before infarction to 17.00 +/- 2.69 mm Hg (p = 0.038). We conclude that this is a useful model of chronic left ventricular failure that is reproducible and applicable to investigations of therapeutic options in chronic heart failure.

Dynamic cardiomyoplasty in chronic left ventricular failure: an experimental model.

Dynamic cardiomyoplasty continues to attract interest as a therapeutic option in the management of heart failure. In a large animal model of ischemic heart failure, we have compared dynamic cardiomyoplasty with both adynamic cardiomyoplasty and a control group. Heart failure was induced by coronary artery ligation in sheep, and under the same anesthetic dynamic cardiomyoplasty (n = 5), adynamic cardiomyoplasty (n = 4), or no further procedure was performed (n = 5). After recovery the animals were housed for a further 3 months. The dynamic cardiomyoplasty underwent a recognized muscle transformation protocol during this period. At terminal studies, the animals were hemodynamically assessed, both under baseline conditions and after colloid volume loading. The data at baseline were compared with unpaired t tests, and the function curves created by volume loading were compared by analysis of variance. Although the changes at baseline were small, there were highly significant improvements in the function curves in the dynamic cardiomyoplasty group when the stimulators were turned on compared with stimulators off (p = 0.005) for cardiac output; p = 0.035 for left ventricular end-diastolic pressure; p = 0.002 for pulmonary artery capillary wedge pressure; p = 0.004 for stroke volume; and p = 0.003 for cardiac power). There were also significant improvements in indices of cardiac performance when the dynamic cardiomyoplasty group was compared with both the control and adynamic cardiomyoplasty groups. We conclude that there is experimental evidence that cardiomyoplasty augments cardiac function in a model of chronic left ventricular failure.

False aneurysm of the right internal mammary artery.

False aneurysm of the internal mammary artery is an uncommon complication of median sternotomy. Clinical and radiological findings of 2 such cases are presented. At operative exploration neither was directly related to the presence of a sternal wire.

Neoplastic angina: a case report.

A 54-year-old Caucasian woman, with a 1-year history of exertional angina was investigated by means of coronary angiography. On injection of contrast into both coronary arteries an unusual area of capillary blushing was seen around the point of a left main stem stenosis. At surgery a mass was seen arising from the area of the aortic root extending around the left main stem. Histology confirmed this to be an aortic paraganglioma. Three-vessel coronary artery bypass grafting was performed and at 6-month follow-up the patient remained symptom free.

Right ventricular dynamic cardiomyoplasty: an experimental model.

The effectiveness of dynamic cardiomyoplasty as a means of haemodynamic support in heart failure remains controversial. We have undertaken a study of right ventricular dynamic cardiomyoplasty in sheep using intravenous propranolol to provoke heart failure. Muscle conditioning was performed with cardiomyostimulators following a previously established protocol. We performed multiple invasive measurements of haemodynamic parameters including arterial blood pressure, cardiac output, pulmonary artery capillary wedge pressure, right ventricular dp/dt and end diastolic pressures. These were performed before induction of heart failure, after induction of heart failure, and with pacing of the cardiomyoplasty flap in established heart failure. Our results confirm that we were able to establish significant heart failure and that subsequent pacing of the conditioned muscle flap was able to return cardiac output and right ventricular function to their pre-failure control levels.

A rare case of multiple right heart myxomas.

Primary tumours of the heart are rare. Myxomas are the most common primary cardiac tumours with an estimated incidence of 0.5 per million population per year. Myxomas are most commonly found in left atrium and are solitary in more than 90% cases. Familial myxomas are rarer and tend to be multiple. We report a rare case of multiple myxomas in the right heart which occurred sporadically, presenting with an episode of pre-syncope.

Derivation and validation of a clinical scoring system to predict the need for an intra-aortic balloon pump in patients undergoing adult cardiac surgery.

The spectrum of patients receiving cardiac surgery are increasing in age and severity of illness. With the reduction of complications caused by the placement of an intra-aortic balloon pump (IABP) there is increasing interest in the placement of an IABP prophylactically. We sought to derive a scoring system to guide the placement of IABPs. A total of 3927 patients from the Blackpool Victoria Open Heart Registry were used to derive a range of clinical decision scores using a range of established and novel statistical techniques. This database included 127 patients who received an IABP. The derived scores and rules were then validated on the North Staffordshire Open Heart Registry, containing 3070 patients, and 161 patients who received an IABP. We derived and validated a clinical score that has a sensitivity of 50% and a specificity of 96.5% in the prediction of those patients requiring an IABP. This was robust in the validation dataset and outperformed the Parsonnet score in this context. Our validated clinical scoring system will be useful both to guide individual clinical decision making and to compare variation of IABP usage among institutions.