Implantation of a novel insertable cardiac monitor: preliminary multicenter experience in Europe

BACKGROUND

The LUX-Dx™ is a novel insertable cardiac monitor (ICM) introduced into the European market since October 2022.

PURPOSE

The aim of this investigation was to provide a comprehensive description of the ICM implantation experience in Europe during its initial year of commercial use.

METHODS

The system comprises an incision tool and a single-piece insertion tool pre-loaded with the small ICM. The implantation procedure involves incision, creation of a device pocket, insertion of the ICM, verification of sensing, and incision closure. Patients receive a mobile device with a preloaded App, connecting to their ICM and transmitting data to the management system. Data collected at European centers were analyzed at the time of implantation and before patient discharge.

RESULTS

A total of 368 implantation procedures were conducted across 23 centers. Syncope (235, 64%) and cryptogenic stroke (34, 9%) were the most frequent indications for ICM. Most procedures (338, 92%) were performed in electrophysiology laboratories. All ICMs were successfully implanted in the left parasternal region, oriented at 45° in 323 (88%) patients. Repositioning was necessary after sensing verification in 9 (2%) patients. No procedural complications were reported, with a median time from skin incision to suture of 4 min (25th-75th percentiles 2-7). At implantation, the mean R-wave amplitude was 0.39 ± 0.30 mV and the P-wave visibility was 91 ± 20%. Sensing parameters remained stable until pre-discharge and were not influenced by patient characteristics or indications. Procedural times were fast, exhibited consistency across patient groups, and improved after an initial experience with the system. Operator Operator feedback on the system was positive. Patients reported very good ease of use of the App and low levels of discomfort after implantation.

CONCLUSIONS

LUX-Dx™ implantation appears efficient and straightforward, with favorable post-implantation sensing values and associated with positive feedback from operators and patients.

A maternal-effect Padi6 variant causes nuclear and cytoplasmic abnormalities in oocytes, as well as failure of epigenetic reprogramming and zygotic genome activation in embryos

Maternal inactivation of genes encoding components of the subcortical maternal complex (SCMC) and its associated member, PADI6, generally results in early embryo lethality. In humans, SCMC gene variants were found in the healthy mothers of children affected by multilocus imprinting disturbances (MLID). However, how the SCMC controls the DNA methylation required to regulate imprinting remains poorly defined. We generated a mouse line carrying a Padi6 missense variant that was identified in a family with Beckwith-Wiedemann syndrome and MLID. If homozygous in female mice, this variant resulted in interruption of embryo development at the two-cell stage. Single-cell multiomic analyses demonstrated defective maturation of Padi6 mutant oocytes and incomplete DNA demethylation, down-regulation of zygotic genome activation (ZGA) genes, up-regulation of maternal decay genes, and developmental delay in two-cell embryos developing from Padi6 mutant oocytes but little effect on genomic imprinting. Western blotting and immunofluorescence analyses showed reduced levels of UHRF1 in oocytes and abnormal localization of DNMT1 and UHRF1 in both oocytes and zygotes. Treatment with 5-azacytidine reverted DNA hypermethylation but did not rescue the developmental arrest of mutant embryos. Taken together, this study demonstrates that PADI6 controls both nuclear and cytoplasmic oocyte processes that are necessary for preimplantation epigenetic reprogramming and ZGA.

Sympathetic nervous system and hypertension in diabetic patients

Although it has been demonstrated that the sympathetic nervous system participates in the genesis of essential hypertension, it is still unclear whether this system can also account for the increased incidence of arterial hypertension in diabetic patients. However, there are some observations which make this hypothesis extremely likely. In fact, it has been demonstrated that in diabetic normotensive patients the reflex control of the sympathetic discharge is normal, but in hypertensive patients there are some derangements of the autonomic nervous tone control which may contribute to increasing the incidence of arterial hypertension in patients with Type 2 diabetes mellitus. In particular, on the one hand, it has been reported that in hypertensive patients hyperinsulinemia is able to induce a reflex activation of the sympathetic tone which is 3-fold higher than that observed in normotensive subjects. On the other hand, it has been demonstrated that this abnormal sympathetic response is particularly harmful in subjects prone to develop essential hypertension since they are characterized by vascular insulin resistance, which plays a permissive role in the development of essential hypertension. Vascular insulin resistance is a type of endothelial dysfunction which impairs the insulin modulation of the vascular effects of sympathetic nervous activation.

Haemodynamic and metabolic effects of rilmenidine in hypertensive patients with metabolic syndrome X. A double-blind parallel study versus amlodipine

OBJECTIVE

To compare the effects of rilmenidine with those of amlodipine on blood pressure, glucose metabolism, plasma lipid concentration and fibrinolysis parameters.

DESIGN

A four-month randomized double-blind, parallel group study.

PATIENTS AND METHODS

Obese hypertensive patients with hypertriglyceridaemia (> or = 2.3 mmol/l) and impaired glucose tolerance (OMS-ADA) were included (n = 52). A placebo run-in period of 2 weeks was followed by 4 months of double-blind treatment with either rilmenidine or amlodipine. Blood pressure was recorded using a mercury sphygmomanometer. Glucose metabolism was evaluated by an oral glucose tolerance test

RESULTS

Of the 52 patients recruited, 47 (21 rilmenidine and 26 amlodipine) completed the 4-month treatment period. The intention-to-treat analysis showed a comparable reduction in systolic and diastolic blood pressure (SBP, DBP) with the two anti-hypertensive treatments (rilmenidine -13.9/-13.5 mmHg; amlodipine - 17.6/-15.0 mmHg). Insulin concentrations under basal conditions and 2 h after a standard oral glucose load did not change significantly after treatment in both groups. Plasma glucose under basal conditions and 2 h after a standard oral glucose load as well as the area under the plasma glucose concentration curve tended to decrease in the rilmenidine group and to increase in the amlodipine group so that the changes in these parameters were significantly different between the two study groups (P= 0.041, P = 0.042 and P = 0.015, respectively). Plasminogen activator inhibitor type 1 (PAI-1) antigen and PAI-1 activity were only decreased in the rilmenidine group (not statistically significant).

CONCLUSION

Our results demonstrate that rilmenidine and amlodipine have a comparable anti-hypertensive effect but only rilmenidine is able to improve glucose metabolism.

Effect of eprosartan and enalapril in the treatment of elderly hypertensive patients: subgroup analysis of a 26-week, double-blind, multicentre study. Eprosartan Multinational Study Group

A double-blind comparator study was performed in 528 hypertensive patients [baseline sitting diastolic blood pressure (SitDBP) 95-114 mmHg]. The primary objective was to compare the incidence of drug-related cough in patients treated with enalapril and eprosartan. The secondary objective was to compare antihypertensive efficacy between treatments. This paper reports the results of a prespecified subgroup analysis performed in the patients under and over 65 years of age recruited into the study. Eprosartan was titrated from 200 mg b.i.d. to 300 mg b.i.d. and enalapril from 5 mg o.d. to 20 mg o.d. over 12 weeks. Hydrochlorothiazide (HCTZ) 12.5-25 mg o.d. could be added where required to the treatment for the final 6 weeks of the titration phase if SitDBP > or = 90 mmHg. Patients received the maximum titrated dosage during the maintenance phase. In the study overall, the incidence of cough at monotherapy endpoint was significantly higher in the enalapril-treated group than in the eprosartan-treated group (p = 0.018). Similar mean changes in blood pressure from baseline were evident with each treatment. The elderly subpopulation mirrored the response of the study as a whole. Both treatments lowered BP with a further reduction evident following the addition of HCTZ at week 18. In conclusion, eprosartan is effective and safe in elderly hypertensive patients. The combination of eprosartan and HCTZ is also well tolerated and provided additional efficacy in those patients not responding to eprosartan alone. Compared with eprosartan enalapril was associated with an increased risk of cough. These results suggest that, irrespective of age, patients may be less likely to discontinue treatment with eprosartan than with an ACE inhibitor.

Distinct vasodilation, without reflex neurohormonal activation, induced by barnidipine in hypertensive patients

Barnidipine is a new 1,4-dihydropyridine calcium antagonist with a strong and long-lasting vasodilatory effect. In order to assess the haemodynamic profile of the antihypertensive effect of barnidipine, a randomized, double-blind study of barnidipine vs nitrendipine was performed in 24 patients with mild to moderate essential hypertension. Following an initial 4-week placebo period, patients whose sitting diastolic blood pressure (SiDBP) was between 95 and 114 mm Hg, and whose sitting systolic blood pressure was between 150 and 219 mm Hg, were randomized (2:1 ratio) to receive either barnidipine (10 mg) or nitrendipine (10 mg) once daily, for a 6-week double-blind period. Subsequently, patients with an SiDBP of less than 90 mm Hg continued for a second 6-week period with the same monotherapy, while patients with an SiDBP of 90 mm Hg or above received double the dose of antihypertensive treatment for the next 6 weeks. Two-dimensional M- and B-mode echocardiography with Doppler flowmetry was performed at the end of both the placebo and active treatment phases. Barnidipine and nitrendipine reduced blood pressure by the same degree (barnidipine: from 165 +/- 2/100 +/- 1 to 145 +/- 2/89 +/- 1 mm Hg, p < 0.01; nitrendipine: from 163 +/- 3/100 +/- 2 to 143 +/- 7/90 +/- 3 mm Hg, p < 0.01) as a result of peripheral vasodilation. This was not accompanied by reflex neurohormonal activation. Moreover, only in the group receiving barnidipine was a significant decrease in plasma noradrenaline observed, both when the patients were in the supine position (from 298 +/- 27 to 214 +/- 21 pg/ml, p < 0.05) and when they were upright (from 472 +/- 37 to 348 +/- 38 pg/ml, p < 0.05).

Dietary sodium restriction impairs endothelial effect of insulin

Hyperinsulinemia and high salt intake represent two independent cardiovascular risk factors. However, it is still unknown whether the change in dietary salt intake may affect the ability of insulin to stimulate whole-body glucose uptake and to modulate endothelial function. Regarding this latter issue, we have recently demonstrated that insulin enhances endothelial-mediated alpha2-adrenergic vasorelaxation. In overnight-fasted, freely moving Wistar-Kyoto rats (10 to 12 weeks old), we assessed whole-body glucose uptake (in milligrams per kilogram per minute) during a euglycemic-hyperinsulinemic clamp (insulin infusion rate, 3 mU x kg(-1) x min(-1)) after 3 weeks of normal (NSD, 2% NaCl), high (HSD, 6% NaCl), and low (LSD, 0.6% NaCl) sodium diet. Three days after the clamp study, rats were killed to assess alpha2-adrenergic vasorelaxation evoked by UK 14,304 (10(-9) to 10(-6) mol/L) in aortic rings in control conditions and after insulin exposure (100 microU/mL). Different sodium intakes did not modify the mean blood pressure or the insulin-stimulated whole-body glucose uptake (NSD: 14+/-1.2, n=16; HSD: 15.4+/-1.7, n=14; LSD: 14.8+/-0.8, n=14; NS). In contrast, we confirmed the ability of insulin to enhance alpha2-adrenergic vasorelaxation during NSD and HSD (delta% of maximal relaxation, NSD: from 32+/-3% to 58+/-3.4%, n=9, P<0.01; HSD: from 33+/-3.8% to 59+/-3.5%, n=8, P<0.01), but this effect was impaired during LSD (delta% maximal relaxation, from 36+/-1.5% to 36+/-3.4%, n=8, NS). In conclusion, our data demonstrate that in Wistar-Kyoto rats, changes in dietary salt intake do not modify the insulin-stimulated whole-body glucose uptake. In contrast, LSD impairs the insulin potentiation of alpha2-adrenergic vasorelaxation, thus suggesting that dietary salt restriction provokes an impairment of insulin effect on endothelial function.

Benefits of combination therapy in hypertensive patients with associated coronary artery disease: a subgroup with specific demands

Although prevention of coronary artery disease (CAD) is one of the main goals of antihypertensive therapy, when first seen hypertensive patients often have associated CAD. These patients need a therapy that can exert an acute anti-ischemic action, such as ad hoc relief of angina pectoris, and can also reduce the incidence of myocardial infarction (MI) or reinfarction. Reduction in blood pressure (BP) alone does not appear to be adequate because in hypertensive patients CAD is a complex and multifactorial process involving not only hemodynamic, neurohormonal, and metabolic factors but also hypertension-induced myocardial and vascular structural changes, which appear independently to contribute to risk for CAD. In theory, antihypertensive combination therapy, by summing the different effects of various drugs, appears to have a greater capacity for comprehensive management of hypertensive patients with CAD. Simultaneous administration of angiotensin-converting enzyme (ACE) inhibitors and calcium-channel blockers appears to be particularly effective. In several clinical trials with long-term follow-up, ACE inhibitor therapy has been associated with a substantial reduction in the risk for major ischemic events. The antiproliferative action of ACE inhibitors on myocardium and the vascular wall, their hemodynamic effects, antiatherogenic actions, neurohormonal attenuation, and certain genetic issues may account for the ability of this class of drugs to reduce the risk for CAD-related events. Although ACE inhibitors can be expected to increase coronary blood flow when the renin-angiotensin system is activated and to reduce BP, ventricular filling pressure, and sympathetic drive, thus far an acute anti-ischemic action of these drugs has not been demonstrated. Unlike ACE inhibitors, which usually have class-specific effects, there are important differences in the clinical effects of various calcium antagonists. The first generation of dihydropyridine calcium-entry blockers has failed to demonstrate efficacy in secondary prevention of coronary artery events. However, verapamil reduces mortality in patients with normal left ventricular function. The antihypertensive efficacy of verapamil, its antiatherogenic action, and its ability to reverse left ventricular hypertrophy, to improve diastolic function, and to interfere with endothelium-derived contracting factors may also account for the improved survival of patients with CAD treated with this drug. Moreover, verapamil is also effective in the treatment of all types of angina because it reduces myocardial oxygen consumption as a result of its hypotensive effect and its ability to reduce heart rate, and it may also improve oxygen delivery to the myocardium because of its action on coronary vasodilatation. It is also important to consider that ACE inhibitors and calcium antagonists often induce the same beneficial effects through different mechanisms, thus allowing a synergistic action when the two classes of drugs are administered together.

Lisinopril in the treatment of congestive heart failure in elderly patients: comparison versus captopril

The present study was performed in order to compare the efficacy, safety, and tolerability of lisinopril, a long-acting angiotensin-converting enzyme (ACE) inhibitor, with captopril, the shorter acting ACE inhibitor available, in the treatment of elderly patients (mean age 70 +/- 0.5 years) with congestive heart failure (mean left ventricular ejection fraction 33.5 +/- 1%). The study was organized according to a double-blind, parallel-group, randomized multicenter protocol. After a 14-day placebo run-in period, patients were randomized to receive either lisinopril 5 mg orally once per day or captopril 12.5 mg orally once per day. The dose of the study drug could be doubled at 2-week intervals for 6 weeks. The maximal dose was lisinopril 20 mg once per day or captopril 25 mg twice per day. The addition of either captopril or lisinopril to a regimen of diuretics caused a significant increase in exercise tolerance assessed by bicycle ergometry after 12 weeks of treatment (530 +/- 21 seconds vs. 431 +/- 13 seconds, p < 0.01; 555 +/- 19 seconds vs. 463 +/- 12 seconds, p < 0.01, respectively). Both drugs significantly increased left ventricular ejection fraction and stroke volume, were equally effective in improving NYHA class, and were well tolerated, with no differences detectable between treatments. The results of this study indicate that lisinopril 5-20 mg once daily is at least as effective and well tolerated as captopril 12.5-50 mg daily in the treatment of elderly patients with congestive heart failure.

[Tetrofosmin: a new compound labeled with 99mTc for the study of myocardial perfusion. Correlations with coronary anatomy in patients with suspected ischemic cardiopathy]

The aim of this study was to investigate the accuracy of quantitative one-day exercise-rest 99mTc tetrofosmin tomography in the identification of patients with suspected coronary artery disease (CAD) and in the detection of single stenosed coronary vessels. Sixty-one patients with suspected CAD and submitted to coronary angiography were examined. All patients were given 2 i.v. injections of 99mTc tetrofosmin, one at peak exercise (370 MBq) and the other (1110 MBq) at rest 3 hours after exercise (images 15-30 min after injection for both studies). All patients with CAD (> or = 50% luminal stenosis) (n = 50) had abnormal 99mTc tetrofosmin tomogram (100% sensitivity). Only one patient without CAD had abnormal 99mTc tetrofosmin tomogram (91% specificity). Overall sensitivity, specificity, and diagnostic accuracy in the detection of single stenosed vessels were 77%, 93% and 85%, respectively. No significant differences among single vascular areas were observed. Sensitivity and diagnostic accuracy in the identification of single stenosed coronary vessels were significantly higher (p < 0.05) in the patients with single-vessel disease (n = 21) than in those with multivessel disease (n = 29). Sensitivity, specificity and diagnostic accuracy in detecting single diseased vessels were similar in the patients without (n = 26) and in those with previous myocardial infarction (n = 35). The results of this study demonstrate that quantitative one-day exercise-rest 99mTc tetrofosmin SPECT imaging is a suitable and accurate technique to identify patients with suspected CAD and to detect single stenosed coronary vessels.

Technetium 99m-labeled tetrofosmin myocardial tomography in patients with coronary artery disease: comparison between adenosine and dynamic exercise stress testing

BACKGROUND

Pharmacologic coronary vasodilation with adenosine, combined with myocardial scintigraphy, is a useful test for the diagnosis of coronary artery disease (CAD) in patients unable to exercise. It has been demonstrated recently that exercise 99mTc-labeled tetrofosmin cardiac imaging can be used for the detection of CAD. However, no data are available comparing 99mTc-labeled tetrofosmin adenosine and exercise tests in the same patients.

METHODS AND RESULTS

The results of adenosine and exercise 99mTc-labeled tetrofosmin myocardial tomography were compared in 41 patients (37 men and four women; mean age 53 +/- 8 years) with suspected or known CAD who underwent coronary angiography. All patients were submitted, on separate days, to three injections of 99mTc-labeled tetrofosmin (740 MBq intravenously): one at rest, one during bicycle exercise, and one during adenosine infusion (140 micrograms/kg/min for 6 minutes with injection of 99mTc-labeled tetrofosmin at 4 minutes). A total of 902 myocardial segments were analyzed quantitatively. One patient had normal coronary vessels, 19 patients had single-vessel CAD, 12 patients had two-vessel CAD, and nine patients had three-vessel CAD (> 50% coronary stenosis) on coronary angiography. Adenosine induced a significant increase in heart rate (88 +/- 16 beats/min at peak vs 72 +/- 11 beats/min at rest; p < 0.01). Systolic and diastolic blood pressure was not significantly different after adenosine infusion compared with rest. Double product was 22931 +/- 7039 at peak exercise and 11229 +/- 3413 after adenosine (p < 0.01). Agreement on the presence of abnormal single-photon emission computed tomography by adenosine and exercise was 100% by quantitative analysis. In all segments a significant relationship between exercise and adenosine 99mTc-99m-labeled tetrofosmin uptake was observed (r = 0.90; p < 0.001). Segmental agreement for regional 99mTc-labeled tetrofosmin uptake score between exercise and adenosine was observed in 737 (82%) of the 902 segments (kappa value of 0.66). Concordance between the two studies for identification of perfusion status was observed in 809 (90%) of the segments (kappa value of 0.80). Sensitivity and specificity for detection of stenosed vessels were not different for dynamic exercise stress testing and adenosine 99mTc-labeled tetrofosmin cardiac tomography.

CONCLUSIONS

Despite different hemodynamic effects, adenosine and dynamic exercise 99mTc-labeled tetrofosmin single-photon emission computed tomographic imaging provides similar information in the diagnosis and localization of CAD.

Adenosine coronary vasodilation quantitative technetium 99m methoxy isobutyl isonitrile myocardial tomography in the identification and localization of coronary artery disease

BACKGROUND

Exercise and dipyridamole 99mTc-labeled methoxy isobutyl isonitrile (MIBI) myocardial scintigraphy have been widely used for the diagnosis of coronary artery disease (CAD). However, only limited data on adenosine 99mTc-labeled MIBI cardiac imaging are currently available. This study was designed to assess the accuracy of quantitative adenosine-rest 99mTc-labeled MIBI tomography in the diagnosis and localization of CAD.

METHODS AND RESULTS

Fifty-seven consecutive patients with suspected CAD who underwent coronary angiography and 22 normal volunteers were studied. All patients underwent 99mTc-labeled MIBI tomography after administration of adenosine (140 micrograms/kg intravenously for 6 minutes) and at rest. A total of 171 vascular coronary territories were analyzed quantitatively. All patients with CAD (> or = 50% luminal stenosis) (n = 55) had abnormal 99mTc-labeled MIBI tomograms. The normalcy rate was 86% by quantitative analysis. Overall sensitivity, specificity, and diagnostic accuracy for detection of individual stenosed vessels were 84%, 87%, and 85%, respectively. In patients with one-vessel CAD (n = 24), sensitivity and diagnostic accuracy in the detection of individual stenosed vessels were significantly (p < 0.05) higher compared with patients with multivessel CAD (n = 31). Moreover, 75% of patients with one-vessel disease showed a scintigraphic pattern characterized by the presence of perfusion defects in only one coronary artery territory, and 74% of patients with multivessel disease showed a scintigraphic pattern characterized by the presence of perfusion defects in two or more coronary artery territories. Sensitivity, specificity, and diagnostic accuracy for detecting individual diseased vessels were similar in patients without previous myocardial infarction (n = 18) compared with those with previous myocardial infarction (n = 39). In myocardial territories related to noninfarcted areas (n = 124), sensitivity and specificity in the detection of stenosed vessels were 75% and 88%. In infarcted areas (n = 47), sensitivity and specificity in the detection of stenosed vessels were 98% and 80% (differences not significant vs noninfarcted areas).

CONCLUSIONS

Adenosine-controlled coronary vasodilation combined with quantitative 99mTc-labeled MIBI tomography is accurate for identifying patients with CAD and localizing individual stenosed coronary arteries.

[Arterial hypertension and atherosclerosis: their epidemiology and physiopathology]

Several epidemiologic studies have demonstrated that hypertensive patients have an increased risk for the development of atherosclerosis. Although the appearance of atherosclerosis only in those parts of vascular system subjected to high blood pressure suggests that the mechanical stress is the principal factor involved in the development of atherosclerosis, the mechanisms underlying the linkage between hypertension and atherosclerosis are not yet completely understood. In fact, the evidence that antihypertensive treatments are not able to abolish the increased incidence of ischemic accidents in hypertensive patients suggests that other cellular and molecular mechanisms are involved in the pathogenesis of atherosclerosis. The pathogenesis of hypertension is a multifactorial process that involves the interaction of genetic and environmental factors which determine the abnormalities of volume regulation, the enhanced vasoconstriction and the remodeling of the arterial wall which is characterized by hypertrophy and proliferation of vascular smooth muscle cells. On the other hand, the increased growth response of vascular smooth muscle cells represents one of the principal characteristics of atherosclerosis. Thus, increased vascular smooth muscle cell growth is a common feature in the pathogenesis of both atherosclerosis and hypertension.

Assessment of systolic wall thickening using technetium-99m methoxyisobutylisonitrile in patients with coronary artery disease: relation to thallium-201 scintigraphy with re-injection

The results of resting planar ECG-gated technetium-99m methoxyisobutylisonitrile (99mTc-MIBI) imaging were compared with those of thallium-201 (Tl) re-injection after exercise-redistribution scintigraphy in 20 patients (19 men, 1 woman, mean age 53 +/- 10 years) with angiographically proven coronary artery disease. Eight normal subjects (seven men, one woman, mean age 50 +/- 8 years) constituted the control group. In these subjects, only resting 99mTc-MIBI imaging was performed. The standardized percent count increase from end-diastole to end-systole was calculated as an index of wall thickening in 13 segments for each study. Regional wall thickening index (WTI) and 99mTc-MIBI uptake were significantly different (P < 0.05) among segments classified as normal, reversible defects, irreversible defects with increased tracer uptake after re-injection (Re+) or irreversible defects with unchanged tracer uptake after re-injection (Re-) on Tl imaging. Furthermore, WTI and 99mTc-MIBI uptake were significantly higher (P < 0.05) in Re- segments with moderate reduction of Tl uptake (> or = 50% of peak activity) than in Re- segments with severe reduction of Tl uptake (< 50% of peak activity). A significant relationship between WTI and the results of Tl scintigraphy was observed (rho = 0.71, P < 0.0001). The percentage of Re- segments with severe reduction of WTI was significantly higher compared to Re+ segments (64% vs 3%, P < 0.01). Furthermore, compared with moderate Re- segments, a significantly higher percentage of severe Re- segments showed a severe reduction of WTI (86% vs 48%, P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

[Evaluation of systolic parietal thickening of the left ventricle using technetium-99m methoxy isobutyl isonitrile. Relationship with coronary anatomy]

Forty-three patients (40 men and 3 women, mean age 54 +/- 9 years) with coronary artery disease underwent 99mTc methoxy isobutyl isonitrile (sestamibi) myocardial scintigraphy and coronary arteriography. Sestamibi uptake and wall thickening index (WTI) were quantitatively evaluated in each myocardial segment. Segments were divided into group 1 (normal coronary arteries, no. = 94), group 2 (coronary artery stenosis 50-99%, no. = 79), and group 3 (coronary artery stenosis 100%, no. = 42). Group 3 segments were subdivided into group 3A (with collaterals, no. = 18) and group 3B (without collaterals, no. = 24) segments. Both sestamibi uptake and WTI were significantly lower (p < 0.01) in group 3 than in groups 1 and 2. However, only WTI was significantly reduced (p < 0.01) in group 3B vs group 3A. Diagnostic capabilities (i.e. identification of segments supplied by stenosed coronary arteries) of sestamibi uptake, WTI, and a combination of both variables with a discriminant function were compared by analysis of receiver operator characteristic curve (ROC) areas. The diagnostic capabilities of sestamibi uptake (ROC area = 0.65 +/- 0.04) were significantly lower (p < 0.05) than those of WTI (ROC area = 0.81 +/- 0.03) and discriminant function (ROC area = 0.83 +/- 0.03). In conclusion, our data suggest that combined analysis of myocardial perfusion and regional ventricular function may increase the diagnostic accuracy of sestamibi myocardial scintigraphy in identifying myocardial segments supplied by stenosed coronary arteries.

Noninvasive evaluation of cardiac hemodynamics during exercise in patients with chronic heart failure: effects of short-term coenzyme Q10 treatment

In patients with chronic heart failure (CHF), the addition of coenzyme Q10 to conventional therapy reduces the hospitalization rate for worsening of heart failure and the incidence of serious cardiovascular complications. The present study was planned to assess the hemodynamic mechanisms underlying this phenomenon. Cardiac hemodynamics was evaluated continuously using an ambulatory radionuclide detector (VEST) which allows a noninvasive monitoring of left ventricular function. Six patients wit CHF (mean ejection fraction (EF): 29%) clinically documented were studied. This study was organized as a randomized double-blind, placebo controlled, cross-over trial. The enrolled patients, after a washout period, underwent the first hemodynamic evaluation with VEST. Subsequently they were randomized to receive placebo or coenzyme Q10 for 4 weeks. At the end of this period they underwent the second VEST study. The third VEST study was performed after a further 4-week period with inverted treatment. Cardiac hemodynamics were evaluated during bicycle exercise. The EF in control conditions (CC) changed from 27 +/- 11%, at rest, to 24 +/- 8%, at peak exercise. During coenzyme Q10 treatment EF showed a significant increase both at rest (33 +/- 13%, P < 0.05 vs CC) and at peak exercise (30 +/- 12%, P < 0.05 vs CC). The same trends were recorded for the stroke volume and the cardiac output. Our results demonstrate that coenzyme Q10 improves cardiac hemodynamic response to exercise in patients with CHF and suggest that noninvasive monitoring of left ventricular function allows a more reliable assessment of therapy efficacy.

[The practical aspects of treatment in heart failure]

Congestive heart failure (CHF) has been treated for several years on empiric basis, until the results of the major clinical trials have made possible a pathophysiological approach to the treatment of patients with CHF. Studies from our laboratories have demonstrated that hemodynamic and neurohormonal responses to acute volume expansion are markedly impaired in patients with dilated cardiomyopathy and mild heart failure (NYHA Class I) and that pretreatment with ACE-inhibitors is able to prevent these abnormal responses. New insights into a more pathophysiological approach to CHF treatment are now possible by the development of new noninvasive techniques for the study of cardiac function. In particular, through radionuclide techniques we were able to demonstrate that patients with CHF show an exercise induced hemodynamic response different from that of normal subjects. Both ACE-inhibitors and digitalis were able to restore a normal response to exercise in patients with CHF.

Effects of angiotensin converting enzyme inhibitors on left ventricular hypertrophy

It is well known that, in patients with essential hypertension, left ventricular hypertrophy (LVH) is an independent risk factor for cardiovascular disease. However, it has been demonstrated that normalisation of arterial pressure, by therapy with antihypertensive drugs, is associated with regression of LVH, although the extent and time-course of this phenomenon depend on the antihypertensive drug used. In particular, angiotensin converting enzyme (ACE) inhibitors seem capable of inducing a faster and more complete reversal of LVH in patients with essential hypertension than other antihypertensive drugs. The mechanisms underlying this property of ACE inhibitors remain unclear, although 2 features of ACE inhibitors may be particularly relevant. The first is their ability to improve large artery compliance, this being a major determinant of LVH. Arterial compliance is reduced in essential hypertension, resulting in increased left ventricular end-systolic stress, which then contributes to the development of LVH. The second possible mechanism by which ACE inhibitors reverse LVH to a greater degree than other antihypertensive drugs may relate to their ability to interfere with the cardiopulmonary receptor control of the circulation. Thus, ACE inhibitors may counteract the neural and hormonal abnormalities that contribute to the maintenance of LVH in hypertensive patients.