Mechanisms leading to reversible mechanical dysfunction in severe CAD: alternatives to myocardial stunning

Effectiveness of cardiogoniometry compared with exercise-ECG test in diagnosing stable coronary artery disease in women

AIMS

To investigate the effectiveness of cardiogoniometry, a novel, non-invasive method, in diagnosing coronary artery disease (CAD) in women and compare it with exercise-ECG test, by using coronary angiography as a reference method.

METHODS

It was a single-centre, case-series study including consecutive female patients with stable angina pectoris (AP) undergoing coronary angiography. Exercise-ECG test, done according to the Bruce protocol, and cardiogoniometry were obtained prior to coronary angiography. Clinically significant CAD has been defined as one or more coronary lesions with >70% stenosis.

RESULTS

Study included 114 consecutive female patients with median age of 64.0 (58.0-71.0) years, out of which 32 (28.1%) had CAD. Cardiogoniometry yielded a total accuracy of 74.6% with a sensitivity of 75.0% (95% CI 56.6-88.5) and specificity of 74.4% (95% CI 63.6-83.4). Exercise-ECG test yielded a total accuracy of 45.1% with a sensitivity of 68.1% (95% CI 42.7-83.6) and specificity 36.6% (95% CI 25.2-50.3). Cardiogoniometry showed higher accuracy than exercise-ECG test ( P < 0.001). Pathological cardiogoniometry was associated with almost nine times higher risk for CAD (OR 8.7, 95%CI 3.4-22.3, P < 0.001), which remained significant after adjustment for age, and hypokinesia.

CONCLUSION

Cardiogoniometry is a non-invasive, easy-to-use and free-of-risk method which showed high effectiveness in diagnosing stable CAD in women and superior to exercise-ECG test. Cardiogoniometry could be introduced as a part of the diagnostic algorithm of screening women for stable CAD and is suitable for use in the primary setting, especially in women unable to undergo stress-testing.

Protective effects of drag-reducing polymers on ischemic reperfusion injury of isolated rat heart

Drag-reducing polymers (DRPs) are blood-soluble macromolecules that can increase blood flow and reduce vascular resistance. The purpose of the present study was to observe the effect of DRPs on ischemic reperfusion (I/R) injury of isolated rat hearts. Experiments were performed on isolated rat hearts subjected to 30 min of ischemia followed by 90 min of reperfusion in Langendorff preparations. Adult Wistar rats were divided into the following five groups: control group, I/R group, group III (I/R and 2×10(-7)  g/ml PEO reperfusion), group IV (I/R and 1×10(-6)  g/ml PEO reperfusion), and group V (I/R and 5×10(-6)  g/ml PEO reperfusion). Left ventricular end-diastolic pressure (LVEDP), left ventricular systolic pressure (LVSP), maximum rate of ventricular pressure increase and decrease ( ± dp/dtmax), heart rate (HR) and coronary flow were measured. Lactate dehydrogenase (LDH) and creatine kinase (CK) activity and coronary flow, myocardial infarction size and cardiomyocytes apoptosis were also assayed. Our results showed that PEO decreased LVEDP and increased LVSP, ± dP/dtmax in group IV and group V compared with the I/R group (all P <  0.05). The coronary flow significantly increased and the activities of LDH and CK in the coronary flow significantly decreased in group IV and group V compared with those in the I/R group (all P <  0.05). Cell apoptosis and myocardial infarction size were reduced in group IV and group V compared with the I/R group (all P <  0.05). Collectively, these results suggested that DRPs had a protective effect on cardiac I/R injury of isolated rat hearts and it may offer a new potential approach for the treatment of acute ischemic heart diseases.

Effects of no-reflow phenomenon on ventricular systolic synchrony in patients with acute anterior myocardial infarction after percutaneous coronary intervention

OBJECTIVES

The aim of this study was to investigate the effect of no-reflow phenomenon on ventricular systolic synchrony via myocardial blush grades (MBGs) in patients with acute anterior myocardial infarction after percutaneous coronary intervention (PCI).

PATIENTS AND METHODS

All patients were divided into two groups and assessed by MBGs. To observe the parameters of the left ventricular function and left ventricular systolic synchrony, equilibrium radionuclide angiography was performed 1 week after PCI and repeated 6 months after acute myocardial infarction (AMI). Measurement data were compared and analyzed by the Student's t-test, and the count data were evaluated by the χ (2) test. A multivariate regression analysis was performed to assess the contribution of confounding factors.

RESULTS

A total of 100 patients were enrolled in this study: 26 in the no-reflow and 74 in the reflow group. There was no significant difference in terms of age, sex, hypertension history, diabetes history, hyperlipidemia history, and smoking history between the two groups. However, the incidence rate of heart failure with Killip's grade ≥2 in the no-reflow group was significantly higher than that in the reflow group (38.46% vs 18.92%, P<0.05). Six months after the AMI-PCI, the left ventricular ejection fraction, peak ejection rate, and peak filling rate in the no-reflow group were significantly lower than those in the reflow group (t=2.21, 2.29, and 2.03, P<0.05 for all comparisons), but the values of the time to peak ejection rate, time to peak filling rate, phase shift, full width at half maximum, and peak phase standard deviation were all higher (t=2.41, 2.46, 2.00, 2.55, and 2.49, P<0.05 for all comparisons), and the incidence rate of major adverse cardiac events in the no-reflow group was also more elevated than that in the reflow group (53.85% vs 8.11%, χ (2)=34.49, P<0.001).

CONCLUSION

The no-reflow phenomenon identified by MBGs reflects the no-reperfusion status in the myocardium in the infarction-related zone after AMI. The directly caused reduction in the left ventricular systolic synchrony performance leads to adverse long-term outcomes in patients with AMI.

Accuracy of cardiogoniometry compared with electrocardiography in the diagnosis of coronary artery disease

Background:

Cardiogoniometry (CGM) is a novel spatiotemporal electrocardiographic method utilizing computer-assisted three-dimensional data on cardiac potentials.

Objectives:

This study compares the accuracy of CGM and electrocardiography (ECG) by detecting coronary artery disease (CAD) with reference to angiography as a well-known gold standard.

Patients and Methods:

A total of 390 patients undergoing coronary angiography with CAD were enrolled. CGM was performed a few hours prior to coronary angiography. A standard 12-lead ECG was recorded after the CGM. The CGM and ECG results were recorded and analyzed by an independent investigator blinded to all patient data and the results of the coronary angiography.

Results:

The coronary angiography showed a normal coronary artery in 263 patients (67.4%). A median of CGM score was 1 (0–2), the minimum score was 0 and maximum score was 8. A total of 90 patients (31%) showed predefined ST-segment/T-wave changes in the resting 12-lead ECG. CGM yielded a sensitivity of 84% and specificity of 81% and the ECG yielded a sensitivity of 29% and specificity of 67% when compared with the coronary angiography.

Conclusions:

CGM is a non-invasive technique recently developed for quantitative three-dimensional vectorial analysis of myocardial activity and detection of ischemia and infarction. This technique is clearly more sensitive and more specific than a standard resting 12-lead ECG.

Comparison of cardiogoniometry and ECG at rest versus myocardial perfusion scintigraphy

BACKGROUND

Cardiogoniometry (CGM) is a novel resting electrocardiac method based on computer-generated three-dimensional data derived from cardiac potentials. The purpose of this study was to determine CGM's and electrocardiography's (ECG) accuracy for detecting myocardial ischemia and/or lesions in comparison with stress/rest myocardial perfusion scintigraphy (single photon emission computer tomography [SPECT]).

METHOD

A cohort of consecutively enrolled patients (n = 100) with suspected or known coronary artery disease (mean age 67.8 years, 52% female) were examined by CGM and resting ECG before stress/rest myocardial scintigraphy.

RESULTS

Pathological scintigraphy findings at adenosine stress perfusion (ASP) and/or rest were conclusively identified in 21 patients. Diagnostic sensitivity was 71% for CGM and 24% for ECG, specificity was 70% for CGM and 95% for ECG. Reversible ischemia was diagnosed in 16 of 21 patients with pathological scintigraphy results. In this subgroup, sensitivity was 67% for CGM and 25% for ECG.

CONCLUSIONS

At rest, the sensitivity of a CGM significantly surmounts that of a standard 12-lead ECG for detection of isolated myocardial ischemia or myocardial lesions revealed by scintigraphy/SPECT; specificity is in a reasonable range. CGM's ease of use and its considerable agreement with the results of myocardial scintigraphy, suggests a possible role for patient screening in the primary care setting.

Comparison of cardiogoniometry and electrocardiography with perfusion cardiac magnetic resonance imaging and late gadolinium enhancement

AIMS

Cardiogoniometry (CGM) is a spatio-temporal five-lead resting electrocardiographic method utilizing automated analysis. The purpose of this study was to determine CGM's and electrocardiography (ECG)'s accuracy for detecting myocardial ischaemia and/or lesions in comparison with perfusion cardiac magnetic resonance imaging (CMRI) and late gadolinium enhancement (LGE).

METHODS AND RESULTS

Forty (n= 40) patients with suspected or known stable coronary artery disease were examined by CGM and resting ECG directly prior to CMRI including adenosine stress perfusion (ASP) and LGE. The investigators visually reading the CMRI were blinded to the CGM and ECG results. Half of the patients (n= 20) had a normal CMRI while the other half presented with either abnormal ASP and/or detectable LGE. Cardiogoniometry yielded an accuracy of 83% (sensitivity 70%) and ECG of 63% (sensitivity 35%) compared with CMRI.

CONCLUSIONS

In this pilot study CGM compares more favourably than ECG with the detection of ischaemia and/or structural myocardial lesions on CMRI.

Equilibrium radionuclide angiography for evaluating the effect of facilitated percutaneous coronary intervention on ventricular synchrony in patients with acute myocardial infarction

BACKGROUND

It is unclear whether facilitated percutaneous coronary intervention (PCI) via a transradial approach therapy is preferable to primary PCI, with improved ventricular synchrony performance (VS), in Chinese patients.

METHODS AND RESULTS

The 152 patients with their first anterior acute myocardial infarction (AMI) were randomized to a primary PCI group or facilitated PCI group. In the 1(st) week and 6(th) month after AMI onset, the parameters of VS were measured by equilibrium radionuclide angiography with ventricular phase analysis. The rate of TIMI grade-3 flow in the infarct-related artery pre-PCI in the facilitated PCI group was higher than that in the primary PCI group (30.56% vs. 8.45%, P=0.001). At the 6(th) month post-AMI, the parameters of time to peak ejection rate, phase shift and peak phase standard deviation were lower than in the primary PCI group (P<0.05, respectively). The incidence of recurrent ischemia and new or worsening congestive heart failure post-AMI in the facilitated PCI group was significantly lower than that in the primary PCI group (2.78% vs. 9.86%, P=0.043; 2.78% vs. 12.68%, P=0.028).

CONCLUSIONS

Facilitated PCI via a transradial approach might significantly inhibit left ventricular remodeling and improve left ventricular function because of the complete, persistent patency of the infarct-related artery with few complications of vessel access and bleeding.

Electrocardiologic and related methods of non-invasive detection and risk stratification in myocardial ischemia: state of the art and perspectives

Background: Electrocardiographic methods still provide the bulk of cardiovascular diagnostics. Cardiac ischemia is associated with typical alterations in cardiac biosignals that have to be measured, analyzed by mathematical algorithms and allegorized for further clinical diagnostics. The fast growing fields of biomedical engineering and applied sciences are intensely focused on generating new approaches to cardiac biosignal analysis for diagnosis and risk stratification in myocardial ischemia.

Objectives: To present and review the state of the art in and new approaches to electrocardiologic methods for non-invasive detection and risk stratification in coronary artery disease (CAD) and myocardial ischemia; secondarily, to explore the future perspectives of these methods.

Methods: In follow-up to the Expert Discussion at the 2008 Workshop on "Biosignal Analysis" of the German Society of Biomedical Engineering in Potsdam, Germany, we comprehensively searched the pertinent literature and databases and compiled the results into this review. Then, we categorized the state-of-the-art methods and selected new approaches based on their applications in detection and risk stratification of myocardial ischemia. Finally, we compared the pros and cons of the methods and explored their future potentials for cardiology.

Results: Resting ECG, particularly suited for detecting ST-elevation myocardial infarctions, and exercise ECG, for the diagnosis of stable CAD, are state-of-the-art methods. New exercise-free methods for detecting stable CAD include cardiogoniometry (CGM); methods for detecting acute coronary syndrome without ST elevation are Body Surface Potential Mapping, functional imaging and CGM. Heart rate variability and blood pressure variability analyses, microvolt T-wave alternans and signal-averaged ECG mainly serve in detecting and stratifying the risk for lethal arrythmias in patients with myocardial ischemia or previous myocardial infarctions. Telemedicine and ambient-assisted living support the electrocardiological monitoring of at-risk patients.

Conclusions: There are many promising methods for the exercise-free, non-invasive detection of CAD and myocardial ischemia in the stable and acute phases. In the coming years, these new methods will help enhance state-of-the-art procedures in routine diagnostics. The future can expect that equally novel methods for risk stratification and telemedicine will transition into clinical routine.

Cardiogoniometric parameters for detection of coronary artery disease at rest as a function of stenosis localization and distribution

Cardiogoniometry (CGM), a spatiotemporal electrocardiologic 5-lead method with automated analysis, may be useful in primary healthcare for detecting coronary artery disease (CAD) at rest. Our aim was to systematically develop a stenosis-specific parameter set for global CAD detection. In 793 consecutively admitted patients with presumed non-acute CAD, CGM data were collected prior to elective coronary angiography and analyzed retrospectively. 658 patients fulfilled the inclusion criteria, 405 had CAD verified by coronary angiography; the 253 patients with normal coronary angiograms served as the non-CAD controls. Study patients--matched for age, BMI, and gender--were angiographically assigned to 8 stenosis-specific CAD categories or to the controls. One CGM parameter possessing significance (P < .05) and the best diagnostic accuracy was matched to one CAD category. The area under the ROC curve was .80 (global CAD versus controls). A set containing 8 stenosis-specific CGM parameters described variability of R vectors and R-T angles, spatial position and potential distribution of R/T vectors, and ST/T segment alterations. Our parameter set systematically combines CAD categories into an algorithm that detects CAD globally. Prospective validation in clinical studies is ongoing.

Negative contractile reserve with low-dose dobutamine in patients with ischemic cardiomyopathy investigated by gated myocardial perfusion SPECT

INTRODUCTION AND OBJECTIVES

To investigate negative contractile responses in the left ventricle during low-dose dobutamine (LDD) gated single-photon emission computed tomography (SPECT) in patients with ischemic cardiomyopathy.

METHODS

Sixty-eight consecutive patients (mean age, 60 + or - 11 years; 7 male) with ischemic cardiomyopathy (i.e., left ventricular ejection fraction [LVEF] < or = 40%) were evaluated using gated-SPECT at rest and during LDD infusion. Associations between a negative contractile reserve (i.e., a > or = 1-grade improvement in wall thickening score with LDD infusion) and scintigraphic viability criteria and coronary angiography findings were analyzed.

RESULTS

Some 42.6% (29/68) of patients had a negative contractile reserve in one or more segments. In 14.7% (n=10), the LVEF decreased by > or = 4% with LDD. These patients had more segments with a negative contractile reserve (2.8 + or - 2.5 vs. 0.87 + or - 0.40; P=.042), and the cut-off value on receiver operating characteristic curve analysis was > or =2 segments with a negative contractile reserve (sensitivity 70%, specificity 74%, positive likelihood ratio 2.71, negative likelihood ratio 0.40). Some 94% (74/79) of segments with a negative contractile reserve were in viable myocardium (i.e. normal or viable on scintigraphy). Twelve of 17 segments with akinesia or severe hypokinesia and a negative contractile reserve satisfied scintigraphic viability criteria, with the majority (10/12) lying in territories supplied by a patent coronary artery.

CONCLUSIONS

A negative contractile reserve was not uncommon in patients with ischemic cardiomyopathy and was associated with a general decrease in left ventricular systolic function. It was observed mainly in myocardial segments that appeared viable on scintigraphy and were supplied by a patent coronary artery.

A servo-controlled canine model of stable severe ischemic left ventricular failure

Reversible left ventricular failure was produced in conscious dogs by compromise of the coronary circulation. In animals with prior left anterior descending coronary artery occlusion, mean left atrial pressure (LAP) was incorporated into an automatic feedback control system used to inflate a balloon cuff on the circumflex (Cfx) coronary artery. The system could produce stable increases in LAP to 15-20 mm Hg. The dominating system transfer function was the ratio of LAP to balloon volume (BV), which was characterized by a fixed delay (5 s), with LAP/BV = (8e(-jomegatau ))/(0.02 + jomega). The system was stabilized by a phase lead network to reduce oscillations of LAP. A total of seven experiments were conducted in three dogs, and testing of inotropic agents was possible in three experiments under stable conditions with the pump off after an hour or more of operation. Problems encountered were 0.003-0.008 Hz oscillations in LAP in three experiments, which could usually be controlled by reducing the system gain. Late stage ventricular fibrillation occurred in all three animals, but defibrillation was easily accomplished after deflating the Cfx balloon. This system produces reversible left ventricular failure solely due to ischemia, thus closely simulating clinical heart failure due to coronary insufficiency.

Equilibrium radionuclide angiography for evaluating the effect of percutaneous coronary intervention on ventricular aneurysm formation and systolic synchrony in patients with acute myocardial infarction

Left ventricular aneurysm (LVA) after myocardial infarction often results in serious complications. So far, when the LVA happened is unclear. Furthermore, it is a question whether percutaneous coronary intervention (PCI) can change or reverse the formation of LVA? And the report about the long term follow-up was rare. So this study was to evaluate the time sequence of the formation of LVA through left ventriculography in large scale of consecutive acute myocardial infarction (AMI) patients and evaluate the influence of PCI at different time after AMI on the change of systolic synchrony through phase analysis of equilibrium radionuclide angiography. The change of serum brain natriuretic peptide (BNP) was also measured to investigate its association with LVA. And follow up to 3 years to record the major adverse cardiac events. Total of 326 consecutive patients of anterior AMI with LVA were enrolled into this study. All patients were divided into four groups according to the time 'onset to balloon': group A (<3 h), group B (> or =3 and < or =6 h), group C (>6 and < or =12 h) and group D (>1 week). The paradox volume image as well as the parameters of left ventricular function and systolic synchrony were measured by equilibrium radionuclide angiography at 1 week and 6th month after AMI. Plasma BNP was measured in different time after AMI. The major adverse cardiac events were recorded up to 3 years. At the 6th month after AMI, left ventricular ejection fraction, peak ejection rate and peak filling rate in group A, B and C were significantly increased than those in group D while phase shift and peak phase standard deviation were decreased significantly (P < 0.05, respectively). At 6th month after AMI, the paradox volume index in group A was lowered than that in group B, C, and D (P < 0.05, respectively). In 18th hour, 5th day and 24th week after AMI, the values of BNP in group D were higher than those in group A, B and C (P < 0.05, respectively). There was not significantly different between group B and group C. Within the 3rd year follow-up, the incidences of angina post-AMI and mortality in group A, B, and C were significantly lowered than those in group D (P < 0.05, respectively). The LVA can formate shortly after the AMI. The early, fully and permanently patency of infraction related artery can effectively inhibit the left ventricular remodeling process, prevent LVA formation, improve its function and prognosis.

Hibernating myocardium: pathophysiology, diagnosis, and treatment

Comprehensive management of patients with chronic ischemic disease is a critically important component of clinical practice. Cardiac myocytes have the potential to adapt to limited flow conditions by adjusting contractile function, reducing metabolism, conserving resources, and preserving myocardial integrity to cope with an oxygen and (or) nutrition shortage. A prime metabolic feature of cardiac myocytes affected by chronic ischemia is the return to a fetal gene pattern with predominance of carbohydrates as the substrate for energy. Structural adaptation with multiple intracellular changes is part of the remodeling process in hibernating myocardium. Transmural heterogeneity, which defines the pattern of injury in ventricular cardiomyocytes and the response to chronic ischemia, is a multifactorial process originating from functional, metabolic, and flow differences in subendocardial and subepicardial regions. Autophagy is typically activated in hibernating myocardium and has been identified as a prosurvival mechanism. Chronic ischemia is associated with changes in the number, size, and distribution of gap junctions and may give rise to conduction disturbances and arrhythmogenesis. Differentiation between viable and nonviable myocardium by assessing sensitivity of inotropic reserve is a crucial diagnostic tool that is correlated with the prognosis and outcome for improved contractility after restoration of blood perfusion in afflicted myocardium.Reliable and accurate diagnosis of ischemic, scar, and viable tissues is critical for recover strategies. Although early surgical reinstitution of blood flow is most effective in restoring physiologic function of the hibernating myocardium, several new approaches offer promising alternatives. Among others, vascular endothelial growth factor and fibroblast growth factor-2 (FGF-2), especially its lo-FGF-2 isoform, have been shown to be effective in rapid neovascularization. Substances such as statins, resveratrol, some hormones, and omega-3 fatty acids can improve recovery effect in chronically underperfused hearts. For patients with drug-refractory ischemia, intramyocardial transplantation of stem cells into predefined areas of the heart can enhance vascularization and have beneficial effects on cardiac function. This review of ischemic injury, its heterogeneity, accurate diagnosis, and newer methods of treatment, shows there is much information and tremendous hope for better management of patients with coronary heart disease.

Muscarinic receptor upregulation in patients with myocardial infarction: a new paradigm

BACKGROUND

Despite the major role attributed to myocardial vagal activity in left ventricular arrhythmogenesis in chronic myocardial infarction, the impact of infarction on left ventricular muscarinic receptor density remains unknown.

METHODS AND RESULTS

Left ventricular muscarinic receptor density was measured in vivo by positron emission tomography using the specific antagonist [(11)C]methylquinuclidinyl benzilate ([(11)C]MQNB) in 11 patients 43+/-20 days after myocardial infarction and 9 healthy volunteers. The extent of myocardial damage was quantified by delayed contrast-enhanced MRI. Three short-axis slices from each subject were analyzed in matched positron emission tomography and MRI images. A 2-injection positron emission tomography protocol was used; [(11)C]MQNB time-activity curves were obtained in 6 regions per slice and fitted to a 3-compartment ligand-receptor model. Four classes of myocardial regions were considered: normal (in volunteers); remote, supplied by healthy or <70% diameter reduction arteries and without MRI signs of damage; potentially damaged, supplied by infarct-related or >70% diameter reduction arteries and without signs of damage; and damaged, with damage. The muscarinic receptor density in remote (67+/-30 pmol/mL tissue; n=86) and potentially damaged (71+/-30 pmol/mL tissue; n=42) regions of patients was higher than in normal regions of volunteers (32+/-17 pmol/mL tissue; n=156; P<0.001). The muscarinic receptor density in damaged regions (42+/-21 pmol/mL tissue; n=58) was reduced compared with remote and potentially damaged regions (P<0.001) but was not significantly different from normal regions in volunteers (P=0.093).

CONCLUSIONS

Vagal control in patients with chronic myocardial infarction involves muscarinic receptor upregulation in remote nondamaged left ventricular regions. Our results suggest that the receptor density remains within normal values in myocardial regions containing damaged tissue.