Previous Inferior Myocardial Infarction Research Articles

Sinus rhythm endocardial mapping for channels identification in ischemic ventricular tachycardia using a modified electrophysiological triad

Abstract Background In a previous study it was demonstrated that an electrophysiological triad was able to identify critical isthmus in atrial flutter (AFL) patients. This triad is based in the Carto® electroanatomical mapping (EAM) version 7, which displays a histogram of the local activation times (LAT) of the tachycardia cycle length (TCL), in addition to the activation and voltage maps. Purpose This study aimed to prospectively assess the ability of a modified electrophysiological triad to identify and localize the ventricular tachycardia's (VT) channels and entrance zones during sinus rhythm mapping. Methods Prospective analysis of a unicentric registry of individuals who underwent ischemic VT ablation with Carto® EAM, all in sinus rhythm. All patients with non-ischemic etiology, lack of high-density EAM or lack of mapping in any of the left ventricle walls or structures were excluded. Areas of late potentials and possible channels of re-entry were compared to a modified electrophysiological triad constituted by: areas of low-voltage (<0.5mV), a site of deep histogram valley (LAT-Valley) with less than 20% density points relative to the highest density zone and a prolonged LAT-Valley duration that included 10% or more of the total activation time mapped. We also assessed the relationship between the pre-valley bar (the LAT histogram bar immediately before the prolonged LAT-Valley) and the channel entrances. Results A total of 14 patients (14 men, median age 70 IQR 64–78 years) were included. All patients presented with ischemic VT and 86% had a previous inferior myocardial infarction. The median number of collected points were 1733 (IQR 1363–2729). All sinus rhythm maps presented with at least 1 LAT-Valley in the analysed histograms. All arrhythmias were effectively treated after undergoing radiofrequency in the LAT-Valley location, either by blocking the channel entrances or scar homogenization ablation strategy. Also, the pre-valley bar in the histogram marked all the channel entrances in the scar borders. No patient had relapse after a clinical follow up of over 6 months. Conclusion In a prospective analysis, a modified electrophysiological triad was able to identify the scar channels in sinus rhythm in all patients. The pre-valley bar in the histogram disclosed the channel entrances. Further studies are needed to assess the usefulness of this algorithm to simplify catheter ablation and improve clinical outcomes. Funding Acknowledgement Type of funding sources: None.

Sinus rhythm endocardial mapping for channels identification in ischemic ventricular tachycardia using a modified electrophysiological triad

Abstract Funding Acknowledgements Type of funding sources: None. Background In a previous study it was demonstrated that an electrophysiological triad was able to identify critical isthmus in atrial flutter (AFL) patients. This triad is based in the Carto® electroanatomical mapping (EAM) version 7, which displays a histogram of the local activation times (LAT) of the tachycardia cycle length (TCL), in addition to the activation and voltage maps. Purpose This study aimed to prospectively assess the ability of a modified electrophysiological triad to identify and localize the ventricular tachycardia’s (VT) channels and entrance zones during sinus rhythm mapping. Methods Prospective analysis of a unicentric registry of individuals who underwent ischemic VT ablation with Carto® EAM, all in sinus rhythm. All patients with non-ischemic etiology, lack of high-density EAM or lack of mapping in any of the left ventricle walls or structures were excluded. Areas of late potentials and possible channels of re-entry were compared to a modified electrophysiological triad constituted by: areas of low-voltage (<0.5mV), a site of deep histogram valley (LAT-Valley) with less than 20% density points relative to the highest density zone and a prolonged LAT-Valley duration that included 10% or more of the total activation time mapped. We also assessed the relationship between the pre-valley bar (the LAT histogram bar immediately before the prolonged LAT-Valley) and the channel entrances. Results A total of 14 patients (14 men, median age 70 IQR 64-78 years) were included. All patients presented with ischemic VT and 86% had a previous inferior myocardial infarction. The median number of collected points were 1733 (IQR 1363─2729). All sinus rhythm maps presented with at least 1 LAT-Valley in the analysed histograms. All arrhythmias were effectively treated after undergoing radiofrequency in the LAT-Valley location, either by blocking the channel entrances or scar homogenization ablation strategy. Also, the pre-valley bar in the histogram marked all the channel entrances in the scar borders. No patient had relapse after a clinical follow up of over 6 months. Conclusion In a prospective analysis, a modified electrophysiological triad was able to identify the scar channels in sinus rhythm in all patients. The pre-valley bar in the histogram disclosed the channel entrances. Further studies are needed to assess the usefulness of this algorithm to simplify catheter ablation and improve clinical outcomes.

Clinical, procedural and long-term outcome of ischemic VT ablation in patients with previous anterior versus inferior myocardial infarction

BackgroundOutcome of ischemic VT ablation may differ between patients with previous myocardial infarction (MI) in relation to infarct localization.MethodsWe analyzed procedural data, acute and long-term outcomes of 152 consecutive patients (139 men, mean age 67 ± 9 years) with previous anterior or inferior MI who underwent ischemic VT ablation at our institution between January 2010 and October 2015.ResultsMore patients had a history of inferior MI (58%). Mean ejection fraction was significantly lower in anterior MI patients (28 ± 10% vs. 34 ± 10%, p < 0.001). NYHA class and presence of comorbidities were not different between the groups. Indication for the procedure was electrical storm in 43% of patients, and frequent implantable cardioverter defibrillator (ICD) therapies in 57%, and did not differ significantly between anterior and inferior MI patients. A mean of 3 ± 2 VT morphologies were inducible, with a trend towards more VT in the anterior MI group (3.1 ± 2.2 vs. 2.6 ± 1.9, p = 0.18). Procedural parameters and acute success did not differ between the groups. During a mean follow-up of 3 ± 2 years, more anterior MI patients had undergone a re-ablation (49% vs. 33%, p = 0.09, Chi-square test). There was a trend towards more ICD shocks in patients with previous anterior MI (46% vs. 34%). After adjusting for risk factors and ejection fraction, multivariable Cox regression analyses showed no significant difference in mortality (p = 0.78) and cardiovascular mortality between infarct localizations (p = 0.6).ConclusionClinical characteristics of patients with anterior and inferior MI are similar except for ejection fraction. Patients with inferior MI appear to have better outcome regarding survival, ICD shocks and re-ablation, but this appears to be related to better ejection fraction when compared with anterior MI.

P779 Use of right ventricular strain analysis to detect right ventricle subtle dysfunction in patients with left ventricular ischemic cardiomyopathy

Abstract Back ground Right ventricular (RV) systolic dysfunction is an independent prognostic marker of several cardiovascular diseases. Cardiac magnetic resonance imaging (CMR) is a gold standard for evaluation of RV ejection fraction and RV structure. However, the CMR is not available in all institution. So some researchers use strain echocardiography to evaluate RV systolic function Purpose Evaluation of different RV functions and prevalence of RV dysfunction in patients with ischemic cardiomyopathy (ICM) (EF &amp;lt; 50%), using echocardiographic conventional methods and RV strain analysis Methods All our patients had ischemic cardiomyopathy (ICM) (EF&amp;lt; 50), patients with previous inferior myocardial infarction were excluded. A standard comprehensive transthoracic echocardiographic assessment of the RV dimensions, conventional systolic parameters: TAPSE, fractional area change FAC, S" velocity, myocardial performance index (RV MPI- RV Tie index ) and diastolic parameters (E/A, E/E", DT). 2 Dimensional speckle tacking echocardiography (2D-STE) for right ventricular global strain analysis (RVGLS): RVGLS total and RVGLS free wall (RVGLS total is a measurement obtained from the average value of all six segments values and RVGLS free wall is the average value from three RV free wall segments) , RV and LV peak systolic strain rate (RV SRs, LV SRs) and early diastolic strain rate (RV SRe, LV SRe) were measured. Results : we enrolled 50 patients (out of 1026 patients over one year ) 37 males (74%) , mean age 60.8 ± 7.4 years, according to RV strain analysis patients were divided into two groups, group I : patients who had normal RV function (RV free wall peak systolic strain PSS ≤-20%), and group II : had impaired RV function (RV free wall PSS &amp;gt;-20%) . there was no statistically significant difference between the two groups as regards LV dimensions, LV EF, LV GLS , LV SRs, RV dimensions nor other RV conventional parameters as TAPSE, FAC, S", or RV MPI. However mean RV GLS in group (I) was -17.52 ± 8.60 % vs -11.66 ± 3.25 % in group (II), (p = 0.003). Mean RV SRs in group (I) was -1.02 ± 0.27 /s vs -0.74 ± 0.38 /s in group (II), (p = 0.001) There was a statistically significant correlation between RV MPI and RV GLS (r = 0.315, p = 0.026), RVSRs and RV GLS (r = 0.656, p &amp;lt; 0.001) and between RV SRs and RVGLS free wall (r = 0.631, p &amp;lt; 0.001). There was a statistically significant correlation between RV SRs and RVGLS free wall in group (I) (r = 0.693, p &amp;lt; 0.001) and in group (II) (r = 0.819, p &amp;lt; 0.001). There was no agreement between TAPSE and RV GLS free wall (Kappa 0.063, p 0.2). MPI was the only conventional parameter that correlated with RV GLS free wall (p0.026). Conclusion RVGLS is a global, more sensitive parameter of RV systolic function compared to commonly used conventional parameters,it correlates better with RV systolic function and may have a more prognostic power for detection of subtle RV dysfunction.

Paraganglioma presenting as stress cardiomyopathy: case report and literature review.

SummaryPheochromocytoma/paraganglioma (PPGL) are neuroendocrine tumors that can secrete catecholamines. The authors describe a challenging case who presented as stress cardiomyopathy and myocardial infarction (MI). A 76-year-old man, with a medical history of Parkinson’s disease, type 2 diabetes mellitus, hypertension, dyslipidaemia and a previous inferior MI in 2001, presented to the emergency department due to chest pain, headaches and vomiting. He also reported worsening blood glucose levels and increasing constipation over the preceding weeks. BP was 185/89 mmHg (no other relevant findings). EKG had ST segment depression in leads V2-V6, T troponin was 600 ng/L (<14) and the echocardiogram showed left ventricular hypokinesia with mildly compromised systolic function. Nevertheless, he rapidly progressed to severe biventricular dysfunction. Coronary angiogram showed a 90% anterior descendent coronary artery occlusion (already present in 2001), which was treated with angioplasty/stenting. In the following days, a very labile BP profile and unexplained sinus tachycardia episodes were observed. Because of sustained severe constipation, the patient underwent an abdominal CT that revealed a retroperitoneal, heterogeneous, hypervascular mass on the right (62 × 35 mm), most likely a paraganglioma. Urinary metanephrines were increased several fold. 68Ga-DOTANOC PET-CT scan showed increased uptake in the abdominal mass (no evidence of disease elsewhere). He was started on a calcium-channel blocker and alpha blockade and underwent surgery with no major complications. Eight months after surgery, the patient has no evidence of disease. Genetic testing was negative for known germline mutations. This was a challenging diagnosis, but it was essential for adequate cardiovascular stabilization and to reduce further morbidity.Learning points:PPGL frequently produces catecholamines and can manifest with several cardiovascular syndromes, including stress cardiomyopathy and myocardial infarction. Even in the presence of coronary artery disease (CAD), PPGL should be suspected if signs or symptoms attributed to catecholamine excess are present (in this case, high blood pressure, worsening hyperglycaemia and constipation).Establishing the correct diagnosis is important for adequate treatment choice. Inodilators and mechanical support might be preferable options (if available) for cardiovascular stabilization prior to alpha blockade and surgery.Laboratory interference should be suspected irrespective of metanephrine levels, especially in the context of treated Parkinson’s disease.

Ventricular fibrillation waveform characteristics differ according to the presence of a previous myocardial infarction: A surface ECG study in ICD-patients

BackgroundCharacteristics of the ventricular fibrillation (VF) waveform reflect arrest duration and have been incorporated in studies on algorithms to guide resuscitative interventions. Findings in animals indicate that VF characteristics are also affected by the presence of a previous myocardial infarction (MI). As studies in humans are scarce, we assessed the impact of a previous MI on VF characteristics in ICD-patients. MethodsProspective cohort of ICD-patients (n=190) with defibrillation testing at the Radboudumc (2010–2013). VF characteristics of the 12-lead surface ECG were compared between three groups: patients without a history of MI (n=88), with a previous anterior (n=47) and a previous inferior MI (n=55). ResultsAs compared to each of the other groups, the mean amplitude and amplitude spectrum area were lower, for an anterior MI in lead V3 and for an inferior MI in leads II and aVF. Across the three groups, the bandwidth was broader in the leads corresponding with the infarct localisation. In contrast, the dominant and median frequencies only differed between previous anterior MI and no history of MI, being lower in the former. ConclusionsThe VF waveform is affected by the presence of a previous MI. Amplitude-related measures were lower and VF was less organised in the ECG-lead(s) adjacent to the area of infarction. Although VF characteristics of the surface ECG have so far primarily been considered a proxy for arrest duration and metabolic state, our findings question this paradigm and may provide additional insights into the future potential of VF-guided resuscitative interventions.

Radiofrequency and cryoenergy endo-epicardical catheter and surgical approach for a case of incessant ventricular tachycardia ablation

A 67-year-old male with previous inferior myocardial infarction and surgical mitral stenosis repair, underwent VT ablation. Electroanatomical mapping showed earliest endocardial activation in the mid inferior ventricular wall, with diastolic potentials preceding surface QRS by 10 ms. Repeated radiofrequency pulses (Navistar-Thermocool, 50 W) …

Changes in the propagation pattern within the conduction channel during sinus rhythm and ventricular tachycardia demonstrated by non-contact mapping: role of late potential activity

Sustained monomorphic ventricular tachycardia (VT) in patients with a previous myocardial infarction is due to re-entry mechanism in areas of slow conduction. The recognition of the pathogenic mechanism and the characterization of the activation pathway are usually obtained by indirect measures with entrainment mapping and pacing manoeuvres. We studied a 61-years-old patient with a history of previous inferior myocardial infarction and we provided the in vivo direct visualization of the critical components of re-entry circuit by non-contact mapping. VT circuit entrance, central pathway, and exit were characterized during the same beat by virtual electrodes and visualized on a three-dimensional map both during sinus rhythm, ongoing VT, and pacemapping. The analysis demonstrated an activation of the conductive channel in opposite directions during the sinus rhythm and ventricular tachycardia. Late potentials during sinus rhythm turned into mid-diastolic activity during VT; non-contact mapping allowed the ablation procedure to be performed in sinus rhythm, targeting the central pathway of the conducting channel and the abolition of VT inducibility.

The value of attenuation correction by hybrid SPECT/CT imaging on infarct size quantification in male patients with previous inferior myocardial infarct

Attenuation correction (AC) has been shown to improve the accuracy of myocardial perfusion single photon emission computed tomography (SPECT) for the detection and evaluation of patients with coronary artery disease. Attenuation artifacts, because of diaphragmatic attenuation, frequently affect the evaluation of the inferior wall, especially in male patients. The aim of this study was to evaluate the value of AC for the assessment of infarct size in coronary artery disease patients after inferior myocardial infarction. Gated-SPECT with Tc-labeled compounds with AC by hybrid SPECT/computed tomography (CT) was performed in 56 male patients with documented previous inferior myocardial infarction. Both corrected and uncorrected SPECT images were processed after motion and scatter correction by ordered-subset expectation maximization iterative reconstruction. When needed, a manual realignment between SPECT and computed tomography (CT) sections was performed. Uncorrected and corrected SPECT images were analyzed for perfusion using a 5-point segmental scoring scale from 0 (normal) to 4 (absent). Summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS) of the inferior left ventricle wall (inferoseptal, inferior, infero-apical and infero-lateral segments) were determined and compared with the regional wall motion score as determined by uncorrected gated-SPECT. The SSS, SRS, SDS for attenuation-uncorrected and attenuation-corrected studies were 14.02 ± 7.9, 9.51 ± 7, 4.5 ± 3.2 and 9.39 ± 7.1, 5.6 ± 6.1, 3.8 ± 2.8, respectively. Differences were statistically significant (P<0.0001) for SSS and SRS but not for SDS. The regional summed rest score of the inferior wall (SRS of inferior segments) showed a better correlation with the regional summed wall motion score of the same segments: R²=0.50 in comparison to uncorrected SRS, R²=0.46. The combination of diaphragmatic attenuation and inferior myocardial infarction determines an artifactual overestimation of infarct size of inferior infarcts. The AC regional perfusion score (SRS) correlates with the regional wall motion score of the inferior wall. AC does not affect the detection and size of residual ischemia (SDS).

Usefulness of gated SPECT myocardial imaging in evaluation of patients with inferior myocardial infarction

Gated single photon emission computed tomography (gated SPECT) myocardial imaging gives useful information about the extent and severity of perfusion abnormalities (PA) and global left ventricular (LV) function in patients with coronary artery disease. The aim of this study was to evaluate by gated SPECT myocardial imaging differences in perfusion scores and LV function between stress and rest in patients with mild left ventricular dysfunction and/or normal function and previous inferior myocardial infarction (IMI) and to detect myocardial stunning. The study included 77 patients (age 53±8.21) with mild left ventricular dysfunction and previous IMI divided into two groups. Group 1 consisted of 34 patients with IMI and additional ischemia on perfusion scan and group 2 with 43 patients with previous IMI without ischemia on perfusion scan. All patients underwent a 2-day stress-rest gated SPECT myocardial imaging protocol with 99m technetium-methoxyisobutylisonitrile ((99m)Tc-MIBI). There was a more significant post-stress to rest decrease in ejection fraction (EFps) in patients with IMI and additional ischemia (group 1) than in patients with IMI (group 2) (-1.5±2.5 vs. 1.5±2.3, p<0.001). In group 1, there was a significant increase in post-stress end-systolic volume (ESVps) in comparison to ESVr (70.4±29.8 vs. 66.2±26.2ml, p=0.044). However, the decrease in EF post-stress to rest did not reach the level of significance (51.7±10.8 vs. 53.2±10.2%, p=0.147). The extent and severity of perfusion abnormalities were higher on stress (SSS) than on rest images (SRS) (13.9±8.6 vs. 8.3±7.8, p<0.001). There was no difference in global LV parameters or perfusion abnormalities in patients in group 2 between stress and rest except for a significant increase in the post-stress EF to rest value (57.9±11.9 vs. 56.2±10.5%, p=0.018). Severe decrease of post-stress EF to rest was found in 12 (16%) patients indicating stunning. In patients with mild left ventricular dysfunction and IMI with additional ischemia there is evidence of a decrease in the post-stress EF with an increase in the post-stress ESV. In addition, a significant association between the decrease of post-stress EF with the extent and severity of perfusion abnormalities was detected. Gated SPECT myocardial imaging has an important role in the evaluation of perfusion and LV function in patients with IMI especially in patients with additional ischemia.

Usefulness of 64-Slice Coronary Computed Tomographic Angiography in the Planning of Percutaneous Coronary Intervention

) with a 2-year history of adult-onset diabetes mellitus pre-sented with dyspnea on exertion and occasional chest discomfort. An electrocardiogram suggested previous inferior wall myocardial infarction of undetermined age. A myocardial perfusion stress test, performed at an outside institution, demonstrated inferior wall myocardial ischemia. The patient was initially unwill-ing to undergo invasive coronary angiography but was amenable to noninvasive, coronary computed tomo-graphic angiography (CCTA). A 64-slice gated CCTA demonstrated only mild narrowing of the left system

Epicardial catheter ablation of ventricular tachycardia using surgical subxyphoid approach

We report the case of a patient presenting with a previous inferior myocardial infarction complicated by incessant monomorphic ventricular tachycardia resistant to antiarrhythmic drugs. Because endocardial catheter ablation failed and because of focal endocardial activation arising from the left ventricular inferior wall, an epicardial location of the reentry circuit was suspected. Catheter mapping of the pericardial space through a surgical subxyphoid approach performed in the electrophysiological laboratory confirmed the epicardial location of the arrhythmogenic substrate and allowed us successfully to ablate and cure the patient. Surgical subxyphoid approach can be performed in the electrophysiological laboratory when epicardial ablation is needed in case of inadvisable, difficult, or failed non-surgical percutaneous access.

Annular Geometry in Patients With Chronic Ischemic Mitral Regurgitation

Although animal studies showed that annular remodeling may be related to the pathogenesis of chronic ischemic mitral regurgitation (CIMR), little was known in humans. A better understanding of the precise 3D geometry of the mitral valvular-ventricular complex in CIMR is needed to devise a better surgical technique. The purpose of the study was to elucidate mitral annular geometry in patients with CIMR using cardiac MRI. Thirty-eight patients with previous inferior or posterior myocardial infarction were studied. With the 3D reconstruction of the mitral annulus and subvalvular apparatus from a series of longitudinal cine MRIs, end-systolic mitral annulus dimensions and 3D geometry were calculated. Patients were grouped by mitral regurgitation grade using echocardiography (> or =2+, n=15 versus < or =1+, n=23). Both septal-lateral and commissure-commissure mitral annular diameters were significantly greater in CIMR(+) patients (35+/-5 versus 30+/-4 mm, P=0.005; 46+/-6 versus 39+/-4 mm, P<0.001, respectively). The length of the fibrous annulus was significantly larger in CIMR(+) patients (28+/-3 versus 24+/-3 mm; P<0.001). The height of the annular "saddle horn" above a best-fit plane was lower in CIMR(+) patients (4.2+/-1.2 versus 6.0+/-1.8 mm; P=0.002), and the annular height to commissural width ratio was significantly lower in CIMR(+) patients (12+/-3 versus 21+/-5%; P<0.001). Patients with CIMR had greater septal-lateral and commissure-commissure mitral annular dimension, larger intertrigonal distance, and flattened saddle shape of mitral annulus. These associated geometric alterations may be important in the pathogenesis of CIMR.

Papillary Muscle Dysfunction Attenuates Ischemic Mitral Regurgitation in Patients With Localized Basal Inferior Left Ventricular Remodeling: Insights From Tissue Doppler Strain Imaging

The purpose of this research was to test whether papillary muscle (PM) dysfunction attenuates ischemic mitral regurgitation (MR) in patients with left ventricular (LV) remodeling of a similar location and extent. Papillary muscle dysfunction could attenuate tethering and MR because of PM elongation. However, variability in the associated LV remodeling, which exaggerates tethering, can influence the relationship between PM dysfunction and MR. In 40 patients with a previous inferior myocardial infarction but without other lesions, the LV volume, sphericity, PM tethering distance, PM longitudinal systolic strain, and MR fraction were quantified by echocardiography. The patients were divided into two groups: group 1 with significant basal inferoposterior LV bulging but without advanced LV bulging involving other territories, therefore with a similar location and extent of LV remodeling, and group 2 without significant LV bulging. The medial PM tethering distance was significantly correlated with the %MR fraction (r2 = 0.64, p < 0.01), and multiple regression analysis identified an increase in the tethering distance as the only independent determinant of the MR fraction in all subjects and also in group 1. The PM longitudinal systolic strain had no significant relationships with MR fraction in all subjects with variable degrees of LV remodeling, but it had a significant inverse correlation with the MR fraction (r2 = 0.33, p < 0.01) in group 1 with LV remodeling of a similar location and extent, indicating that PM dysfunction is associated with less MR. Papillary muscle dysfunction, reducing its longitudinal contraction to induce leaflet tethering, attenuates ischemic MR in patients with basal inferior LV remodeling.

Papillary muscle dysfunction attenuates ischemic mitral regurgitation in patients with localized basal inferior left ventricular remodeling

Objectives The purpose of this research was to test whether papillary muscle (PM) dysfunction attenuates ischemic mitral regurgitation (MR) in patients with left ventricular (LV) remodeling of a similar location and extent. Background Papillary muscle dysfunction could attenuate tethering and MR because of PM elongation. However, variability in the associated LV remodeling, which exaggerates tethering, can influence the relationship between PM dysfunction and MR. Methods In 40 patients with a previous inferior myocardial infarction but without other lesions, the LV volume, sphericity, PM tethering distance, PM longitudinal systolic strain, and MR fraction were quantified by echocardiography. The patients were divided into two groups: group 1 with significant basal inferoposterior LV bulging but without advanced LV bulging involving other territories, therefore with a similar location and extent of LV remodeling, and group 2 without significant LV bulging. Results The medial PM tethering distance was significantly correlated with the %MR fraction (r2= 0.64, p < 0.01), and multiple regression analysis identified an increase in the tethering distance as the only independent determinant of the MR fraction in all subjects and also in group 1. The PM longitudinal systolic strain had no significant relationships with MR fraction in all subjects with variable degrees of LV remodeling, but it had a significant inverse correlation with the MR fraction (r2= 0.33, p < 0.01) in group 1 with LV remodeling of a similar location and extent, indicating that PM dysfunction is associated with less MR. Conclusions Papillary muscle dysfunction, reducing its longitudinal contraction to induce leaflet tethering, attenuates ischemic MR in patients with basal inferior LV remodeling.

Ablación endocárdica del sustrato de taquicardia ventricular postinfarto durante ritmo sinusal

Radiofrequency ablation of ventricular tachycardia requires good tachycardia tolerance during mapping and entrainment, and this limits its application. We present our initial experience with ventricular tachycardia ablation during sinus rhythm in 7 patients with previous inferior myocardial infarction. Seven men, 56-70 years old (mean +/- SD, 65 +/- 4.5) were included in the study. Ventricular tachycardia was unstable in 6 and in 1 it was induced non-sustained. The scar was localized by recording low-voltage, fragmented electrograms (< 2 mV). Ventricular tachycardia "exit" was localized by pace-mapping in sinus rhythm. Radiofrequency lines were made radially, point by point, from normal to scarred tissue. One of the lines crossed the exit area. The objective was to achieve non-inducibility. Sustained clinical ventricular tachycardia was induced in 6 and non-sustained in 1. Two-four lines were performed per patient with 11-28 (21 +/- 5.4) radio frequency applications. The procedure duration was of 130-280 min (230 +/- 61) and being 49-75 min (63 +/- 7.9) for fluoroscopy. There were no complications. Clinical ventricular tachycardia became non-inducible in 6, although in 4 a rapid (cycle < or = 250 ms), non-clinical ventricular tachycardia remained inducible. Defibrillators were implanted in the patient remaining inducible for clinical ventricular tachycardia and another with > 60 tachycardia episodes the previous week. During 3-22 months (13.8 +/- 5.9) of follow-up, 1 patient died of heart failure at 20 months and another received 3 defibrillator shocks for VT at 13 months. There were no other episodes of ventricular tachycardia, syncope or sudden death. This preliminary experience suggests that radiofrequency ablation of post-infarction ventricular tachycardia substrate is possible during sinus rhythm, suggesting that radiofrequency ablation may be applicable in a large proportion of patients with post-infarction sustained ventricular tachycardia.

Comparison between planar and tomographic radionuclide ventriculography for detecting inferior wall motion abnormalities

Gated planar radionuclide ventriculography is routinely used for the detection of regional wall motion abnormalities of the left ventricle. However, for inferior wall motion abnormalities, sensitivity is known to be low in the left anterior oblique 'best septal' projection, although improved if a left posterior oblique (LPO) view is also acquired. Gated tomography of the cardiac blood pool is now available. This study compared the sensitivity of planar 'best septal' projection, LPO and tomographic radionuclide ventriculography in the detection of inferior wall motion abnormalities. Thirty-two patients consisting of 18 with previous inferior myocardial infarction and 14 normal controls were studied. All patients underwent equilibrium planar 'best septal', planar LPO and then tomographic radionuclide ventriculography. Inferior wall motion abnormality was detected in 'best septal' in eight (44%) patients, LPO in 12 (67%) and tomography in 17 (94%) patients, respectively. Tomographic radionuclide ventriculography was best at detecting inferior wall motion abnormality while planar LPO projection is better than 'best septal' projection.

Chronic aneurysmatic dilatation: a possible source of lethal embolization in patients with acute myocardial infarction undergoing thrombolysis

Left ventricular thrombosis is relatively common after acute myocardial infarction, especially in the anterior site, and represents a possible cause of potentially lethal peripheral embolization [1]. Therefore, several studies have been performed in order to assess the efficacy of different antithrombotic drugs in resolving the detected thrombi or reducing their embolic potential. Fibrinolytic agents appear effective in this regard: in the majority of cases, they produce complete lysis and resolution of the thrombi. However, this treatment may itself cause embolic complications by producing a rapid fragmentation of thrombus and the subsequent emission of disrupted portions of the intracardiac mass into the systemic vascular bed [2]. This dramatic effect of thrombolysis has suggested the possibility that even the standard treatment of acute myocardial infarction with fibrinolysis implies a danger of embolization in those patients in whom a left ventricular thrombus may be present either from a previous myocardial infarction or from a very early thrombus development. However, this hypothesis has not yet been confirmed by direct observation. We report the case of a patient with a first acute anterior myocardial infarction, in whom the thrombolytic treatment induced lysis and embolization from a left ventricular thrombus present in an aneurysmatic dilatation of the infero-posterior wall due to a previous inferior myocardial infarction.

Chronic aneurysmatic dilatation: a possible source of lethal embolization in patients with acute myocardial infarction undergoing thrombolysis

<h2>Abstract</h2> Left ventricular thrombosis is relatively common after acute myocardial infarction, especially in the anterior site, and represents a possible cause of potentially lethal peripheral embolization [1]. Therefore, several studies have been performed in order to assess the efficacy of different antithrombotic drugs in resolving the detected thrombi or reducing their embolic potential. Fibrinolytic agents appear effective in this regard: in the majority of cases, they produce complete lysis and resolution of the thrombi. However, this treatment may itself cause embolic complications by producing a rapid fragmentation of thrombus and the subsequent emission of disrupted portions of the intracardiac mass into the systemic vascular bed [2]. This dramatic effect of thrombolysis has suggested the possibility that even the standard treatment of acute myocardial infarction with fibrinolysis implies a danger of embolization in those patients in whom a left ventricular thrombus may be present either from a previous myocardial infarction or from a very early thrombus development. However, this hypothesis has not yet been confirmed by direct observation. We report the case of a patient with a first acute anterior myocardial infarction, in whom the thrombolytic treatment induced lysis and embolization from a left ventricular thrombus present in an aneurysmatic dilatation of the infero-posterior wall due to a previous inferior myocardial infarction.

Analysis of Right Ventricular Kinesis by Means of Transesophageal Echocardiography:

The evaluation of right ventricular (RV) kinesis by two-dimensional echocardiography represents a difficult task. Transthoracic echocardiography can visualize the RV in several projections, but the image quality and the variability of imaging views usually do not allow quantitative analysis. We investigated the potential of transesophageal echocardiography (TEE) for evaluating RV global function and regional kinesis, in 32 controls and in 16 patients with inferior myocardial infarction (MI) and asynergy involving the inferior wall of both ventricles. Good-quality images of at least one horizontal section of the RV were obtained in 73% of subjects by conventional, 90 degrees sector and in 100% of subjects by wide-angle, "panoramic" sector. Images of the RV in short-axis view at medium level were acquired and evaluated in 93% of cases, but at basal and apical levels only in 67% and 39%, respectively. The low percentage of successful detection and evaluation of the RV at apical level can be explained by prominent motion and trabeculation of the apex. Global systolic area changes (SAC) in controls attained similar values at apical and medium levels (60% and 59%, respectively), but were significantly lower (48%, P less than 0.05) at basal level. In patients with previous inferior MI and inferoposterior asynergy, global SAC were significantly (P less than 0.01) lower at medium and basal levels (32% and 27%, respectively) compared with controls. Regional kinesis of RV was assessed as segmental SAC in 12 different segments, by fixed and float system of center of cavity.(ABSTRACT TRUNCATED AT 250 WORDS)