Endocan: a novel biomarker associated with well-developed coronary collateral circulation in patients with stable angina and chronic total occlusion.

Angiogenesis and arteriogenesis have a crucial role in the formation of coronary collateral vessels. It has been shown that endocan and vascular cell adhesion molecule-1 (VCAM-1) are potential angiogenetic factors. We investigated the relationship between serum endocan levels and grade of coronary collaterals, and also the correlation of endocan levels with serum VCAM-1 levels. Patients with stable angina and at least one total coronary occlusion at invasive coronary angiography were included in our study. Collateral degree was graded according to Rentrop and Cohen's classification. Patients who had grade 0 or 1 collateral vessels were included in the poorly-developed collateral group, and those with grade 2 or 3 coronary collateral vessels were included in the well-developed collateral group. Serum endocan and VCAM-1 levels were significantly higher in the well-developed collateral group (436.6 ± 213.3 ng/mL vs. 216.1 ± 78.5 ng/mL, p < .001; 11.02 ± 6.58 ng/mL vs. 6.78 ± 1.14 ng/mL, p < .001, respectively). In a logistic regression analysis, only serum endocan level remained as an independent predictor for good collateral development. In the ROC curve analysis, 282 ng/mL endocan level had an a 82 % sensitivity and 86 % specificity for prediction of the well-developed collateral group. Higher endocan level was related to better coronary collateral development. In the event that these results are confirmed in further studies, endocan may be considered as an anti-ischemic treatment strategy in order to improve collateral development.

Galectin-3 correlates with arrhythmogenic right ventricular cardiomyopathy and predicts the risk of ventricular -arrhythmias in patients with implantable defibrillators.

Background Arrhythmogenic right ventricular dysplasia (ARVD) is a heritable disorder characterized by fibro-fatty replacement of right ventricular myocytes, increased risk of ventricular arrhythmias, and sudden cardiac death. Galectin-3 (GAL3) is known to play an important role in a number of fibrotic conditions, including cardiac fibrosis. Many studies have focused on the association between GAL3 levels and cardiac fibrosis in heart failure. However, the role of GAL3 in the pathogenesis of ARVD and ventricular arrhythmias has not yet been evaluated thoroughly. The aim of this study was to explore GAL3 levels in patients with ARVD and its association with ventricular arrhythmias. Methods Twenty-nine patients with ARVD and 24 controls were included. All patients with ARVD had an implantable cardiac defibrillator (ICD) for primary or secondary prevention. Ventricular arrhythmia history was obtained from a chart review and ICD data interrogation. Galectin-3 levels were measured using an enzyme-linked immunosorbent assay. Results Patients with ARVD had higher plasma GAL3 levels (16.9 ± 2.6 ng/mL vs 11.3 ± 1.8 ng/mL, P < 0.001) than the control group. Ten patients had sustained or non-sustained ventricular arrhythmias during follow-up. In the multivariable analysis, left ventricular disease involvement (HR: 1.05; 95% CI: [1.01-1.12]; P = 0.03); functional capacity >2 (HR: 1.21; 95% CI: [1.13-1.31]; P < 0.005); and GAL3 levels (HR: 1.05; 95% CI: [1.00-1.11]; P = 0.01) independently predicted VT/VF. Conclusion We demonstrated that serum GAL3 was significantly elevated in patients with ARVD. Also, serum GAL 3 levels could be regarded as a candidate biomarker in the diagnosis of ARVD which needs to be tested in larger prospective studies. In addition, GAL3 levels were higher in patients with VT/VF as compared with those without VT/VF.

Combined analysis of unipolar and bipolar voltage mapping identifies recurrences after unmappable scar-related ventricular tachycardia ablation.

AIMS: Scars causing ventricular tachycardia can extend deep to and beyond bipolar low-voltage areas (LVAs) and they may be a reason for endocardial ablation failure. Analysis of endocardial unipolar voltage maps has been used to detect scar transmurality and epicardial scar. We hypothesized that endocardial unipolar LVA around the overlying bipolar LVA may predict endocardial ablation recurrence in patients with structural heart disease undergoing substrate modification. METHODS AND RESULTS: Twenty consecutive patients with structural heart disease (11 ischaemic and 9 non-ischaemic cardiomyopathy) and undergoing substrate modification due to unmappable ventricular tachycardia (VT) (18 males, 51 ± 11 age, LVEF: 36 ± 7%) were retrospectively reviewed. Bipolar LVA defined as <1.5 mV and unipolar LVA defined as <8.3 mV, respectively, on electro-anatomic mapping system. Peripheral unipolar LVA (pUni-LVA) surrounding bipolar LVA was measured and compared patients with and without VT recurrence at 6-month follow-up period. : Mean unipolar voltage and mean bipolar voltage was 6.26 ± 4.99 and 1.90 ± 2.30 mV, respectively. Bipolar voltage and unipolar voltage in corresponding points were correlated (r = 0.652, P = 0.0001). In all patients, unipolar LVAs were larger than the bipolar LVAs. Bipolar LVA (91.1 ± 93.5 vs. 87.5 ± 47.5 cm(2), P = 0.91) and unipolar LVA (148.1 ± 96.3 vs. 104.7 ± 44.2 cm(2), P = 0.21) were similar in patients with and without VT recurrence, respectively. Peripheral unipolar LVA was significantly larger in patients with VT recurrence than without (57.0 ± 40.4 vs. 17.2 ± 12.9 cm(2), P = 0.01). CONCLUSION: In patients with structural heart disease and unmappable VT, pUni-LVA surrounding bipolar scar predicts recurrence of VT ablation. The results of this pilot study highlight the importance of intramural/epicardial substrate on endocardial VT ablation outcome.

Infarct characteristics by CMR identifies substrate for monomorphic VT in post-MI patients with relatively preserved systolic function and ns-VT.

BACKGROUND: The extent of peri-infarct zone (PIZ) by contrast-enhanced cardiac magnetic resonance (ce-CMR) has been related to inducibility of ventricular arrhythmia in patients with ischemic cardiomyopathy. However, this relationship has not been established in postmyocardial infarction (post-MI) patients with relatively reserved left ventricular (LV) systolic function yet. In this study, we investigated myocardial scar size and characteristics and its relationship with ventricular arrhythmia inducibility in patients with relatively preserved LV systolic function. METHODS: This study enrolled 28 post-MI patients with a left ventricular ejection fraction between 40% and 50% and nonsustained ventricular tachycardia who underwent programmed ventricular stimulation (PVS) for risk stratification. Cine and gadolinium-enhanced cardiac magnetic resonance imaging was performed before PVS. A computer-assisted algorithm quantified the total scar (TS) size and divided it into the dense scar (DS) and the PIZ based on signal intensity thresholds (>6 standard deviations [SDs] and 2 to 6 SDs above remote normal myocardium, respectively). Scar measurements were determined and compared among noninducible (n = 19) and inducible patients (n = 9). RESULTS: The groups had similar baseline clinical characteristics. The LV masses, volumes, and ejection fractions did not differ significantly between the groups. For the inducible versus noninducible patients, DS percent was similar (3.11 ± 1.02% vs 3.44 ± 0.79%, P = NS). PIZ percent (28.02 ± 7.49% vs 19.86 ± 7.82%, P = 0.01) and TS percent (31.14 ± 7.96% vs 23.31 ± 8.21%, P = 0.02) were associated with inducibility of monomorphic VT. Multivariate analysis demonstrated that PIZ percent (P = 0.021, OR [odds ratio] 1.18, 95% CI [confidence interval] 1.03-1.35), and TS percent (P = 0.03, OR 1.15, 95% CI 1.01-1.30) were independent predictors of inducibility. CONCLUSIONS: Higher PIZ percent and TS percent were correlated with increased ventricular inducibility. These data support the hypothesis that ce-CMR may be used to identify the substrate for ventricular arrhythmia in this cohort.

Usefulness of T(peak) -T(end) interval to distinguish arrhythmogenic right ventricular cardiomyopathy from idiopathic right ventricular outflow tract tachycardia.

BACKGROUND: The two predominant etiologies of right ventricular tachycardia (VT) are arrhythmogenic right ventricular cardiomyopathy (ARVC) and idiopathic VT arising from the right ventricular outflow tract (RVOT). Discrimination between these two entities is critical, as their prognoses and therapeutic options differ. The Tpeak -Tend (Tpe) interval reflects the transmural repolarization dispersion and its prolongation is associated with high mortality. METHODS: We compared the sinus rhythm electrocardiogram (ECG) of 43 patients (24 male, 43 ± 16 years) with VT originating from right ventricle. Five patients under antiarrhythmic drug therapy were excluded. Tpe interval was measured in each precordial leads and compared among patients with ARVC and RVOT-VT. RESULTS: Twenty-five patients (16 male, 42 ± 16 years) met the Task Force criteria for the diagnosis of ARVC, and 13 patients (seven male, 45 ± 14 years) had idiopathic RVOT tachycardia. Patients with ARVC had significantly prolonged Tpe intervals in all precordial leads compared to patients with idiopathic RVOT VT (137.1 ± 32.6 ms vs 93.8 ± 16.9 ms; P < 0.001 in V1, 133.2 ± 35.5 ms vs 104.7 ± 16.9 ms; P = 0.01 in V2, 125.7 ± 31.5 ms vs 99.1 ± 19.6 ms; P = 0.09 in V3, 121.9 ± 26.5 ms vs 92.3 ± 19.7 ms; P = 0.001 in V4, 123.1 ± 26.5 ms vs 99.5 ± 20:1 ms; P = 0.04 in V5 and 126.9 ± 32.2 ms vs 89 ± 11.3 ms; P < 0.001 in V6, respectively). For the diagnosis of ARVC, Tpe cut-off value of 97 ms in V1 had 84% sensitivity and 62% specificity (area under curve = 0.880). CONCLUSION: In patients with VT of RV origin, the prolonged Tpe interval in sinus rhythm electrocardiogram supports the diagnosis of ARVC.

Evaluation of human immunodeficiency virus infection-related left ventricular systolic dysfunction by tissue Doppler strain echocardiography.

OBJECTIVE: Cardiovascular involvement causes significant morbidity and mortality among patients with human immunodeficiency virus (HIV) infection. Since the introduction of highly active antiretroviral treatment (HAART), subtle changes in left ventricular (LV) function, which may be clinically silent, have become more pronounced in HIV patients. Echocardiographic strain imaging (SI) may detect subclinical myocardial dysfunction at an earlier stage compared with conventional echocardiography. The aim of this study was to evaluate tissue Doppler-derived LV strain and strain rate (SR) along with conventional measures of LV function in asymptomatic, stable adult HIV patients on HAART. METHODS: Twenty-one patients with HIV infection (mean age: 37.8 ± 11.9 years, 11 males) who had no cardiovascular complaints and 27 healthy volunteers (mean age: 40.9 ± 5.8 years, 14 males) were enrolled. Traditional parameters including LV ejection fraction (EF) were measured along with tissue velocity imaging (TVI) and tissue Doppler SI parameters using transthoracic echocardiography. RESULTS: The mean duration of HIV infection was 30.8 ± 25.1 (3-120) months. The mean LVEF in HIV group was within normal limits but lower than controls (64.5% ± 10.2% vs. 72.2% ± 6.4%, P = 0.003). There were no differences in other major traditional measures, as well as TVI parameters between groups. LV systolic strain and SR parameters were impaired indicating subtle LV systolic dysfunction in HIV group. No difference in diastolic function was observed between groups. CONCLUSION: Left ventricular systolic strain parameters may be utilized to demonstrate subtle LV systolic dysfunction in asymptomatic HIV patients.

Atrioventricular complete block occurring 12 years after successful ablation of slow-slow atrioventricular nodal reentrant tachycardia.

Atrioventricular nodal reentrant tachycardia (AVNRT) is the most frequent form of paroxysmal supraventricular tachycardia. Selective radiofrequency (RF) catheter ablation of the slow pathway is an ideal method for treatment of patients with AVNRT. Complete atrioventricular block is a rare but serious complication of RF ablation, and primarily occurs during or immediately after the procedure. We report on a 45-year-old woman who underwent successful ablation for symptomatic AVNRT at the age of 33. She presented with paroxysmal complete AV block, which developed twelve years after RF ablation of the slow pathway and a permanent DDD pacemaker was implanted. As seen in the case we report, complete AV block complicating RF ablation can occur years after the procedure.

Successful stenting of a left main coronary artery occlusion as a complication of RF ablation for Wolff-Parkinson-White syndrome.

Wolff-Parkinson-White (WPW) syndrome is a disorder characterized by presence of an accessory pathway that predisposes patients to tachyarrhythmias and sudden death. Radiofrequency ablation (RFA) is both effective and safe for patients with symptomatic tachyarrhythmias mediated by accessory atrioventricular pathways. During the procedure, fatal complications may occur but it is considered low in relation to the morbidity associated with the WPW syndrome. Coronary artery occlusion, as a complication of an RF catheter ablation, is quite rare. In this report, we present a 56-year-old male patient with a left main coronary artery (LMCA) occlusion during the ablation of left anterolateral wall accessory pathway. It should be kept in mind if the patient complains of new onset of severe chest pain, an immediate angiography should be performed.

Brugada type 1 electrocardiogram unmasked by a febrile state following syncope.

Brugada syndrome is a genetic disease characterized by persistent or transient ST elevation in the right precordial electrocardiogram (ECG) leads with or without right bundle branch block. It represents an increased risk for sudden cardiac death despite a structurally normal heart. Brugada-type ECG can be unmasked and induced by several circumstances. We report on a 24-year-old male patient who experienced a syncopal episode and manifested Brugada type 1 ECG during a febrile state. His ECG changed to normal after treatment of fever. A single-chamber ICD was implanted to the patient because of syncope, fever-induced type I Brugada ECG pattern, and ventricular fibrillation during ajmaline challenge.

Silent myocardial dysfunction in vitamin D deficiency.

INTRODUCTION: Vitamin D (VD) deficiency is a common disease that occurs in all stages of life. A growing number of studies call attention to the relationship between VD deficiency and cardiovascular disease. The aim of this study was to investigate the effect of VD on subclinical left ventricular (LV) function in diabetic and non-diabetic patients with no significant coronary artery disease. MATERIAL AND METHODS: We recruited 140 patients (80 diabetics and 60 non-diabetics) with symptoms of stable ischemic heart disease who underwent coronary angiography and who had no significant coronary artery disease in our clinic. The 25(OH)D3 levels were measured and patients who had 25-(OH)D3 levels below 20 ng/dl were defined as the VD deficient group. In addition to conventional echocardiographic parameters, tissue Doppler echocardiography was used for LV diastolic functions and 2D speckle tracking strain echocardiography (2D STE) for evaluating the longitudinal deformation indices of the LV myocardium. RESULTS: In all groups, LV global longitudinal strain (GLS) was significantly impaired in patients with VD deficiency (p < 0.001) compared to patients without VD deficiency. LV global longitudinal strain rate (GLSR) was significantly impaired in patients with VD deficiency (p = 0.003). The GLS was negatively associated with 25-(OH)D3 in the VD deficiency group (r = -0.52623, p < 0.001). Conversely, GLS was positively associated with 25-(OH)D3 levels in the normal VD group (r = 0.28, p = 0.048). CONCLUSIONS: VD deficiency is associated with impaired myocardial GLS. The present study demonstrated that VD deficiency may be the cause of subclinical myocardial dysfunction in patients with or without diabetes mellitus and no history of significant coronary artery disease.

Angiotensin-converting enzyme gene polymorphism in arrhythmogenic right ventricular dysplasia: is DD genotype helpful in predicting syncope risk?

INTRODUCTION: Arrhythmogenic right ventricular dysplasia (ARVD) is a heritable disorder characterised by fibrofatty replacement of right ventricular myocytes and increased risk of ventricular arrhythmias and sudden cardiac death. Angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism affects myocardial ACE levels. DD genotype favours myocardial fibrosis and is associated with malignant ventricular tachycardia. The aim of this study was to explore ACE gene polymorphism in ARVD patients. METHODS: Twenty-nine patients with ARVD and 24 controls were included. All ARVD patients had documented sustained ventricular tachycardia. Thirteen patients had syncopal episodes. Six patients were resuscitated from sudden cardiac death. ACE gene polymorphism was identified by polymerase chain reaction technique. RESULTS: There was no significant difference in DD genotype frequency between ARVD patients and controls (44.8% vs. 45.8%, p=0.94). However, DD genotype frequency was significantly higher in ARVD patients with syncopal episodes compared to those without syncope (69.2% vs. 25.0%, p=0.017, odds ratio:6.750, 95% confidence interval: 1.318-34.565). DD genotype was detected in higher frequency also in patients with a family history of sudden cardiac death (66.7% vs. 39.1%,p=0.36). CONCLUSION: High prevalence of DD genotype in ARVD patients with syncope suggests that ACE I/D polymorphism might be useful in identifying high-risk patients for syncope.

Assessment of early changes in the segmental functions of the left and the right ventricles after biventricular pacing in heart failure: a study with tissue Doppler imaging.

Tissue Doppler imaging allows assessment of systolic and diastolic regional ventricular function. The aim of this study was to assess early changes in regional systolic and diastolic functions and differences in transition time to contraction between the ventricles after cardiac resynchronization therapy. Fourteen patients were included, who underwent echocardiography before and 1 month after resynchronization. The difference between transition time to contraction of left and right ventricles decreased to 24.4 +/- 10.7 milliseconds from 65.3 +/- 18.2 milliseconds after resynchronization therapy (P = .001). There was a significant relation between the decrease in difference between transition time and increase in ejection fraction (r = 0.80, P = .002). Early or late diastolic myocardial motion increased in 7 segments of left and 2 segments of right ventricles. Systolic myocardial motion increased in 7 segments of left and in all segments of right ventricles. Resynchronization therapy improved systolic and diastolic functions in both ventricles. The difference between transition time to contraction of ventricles might be helpful in estimating optimal resynchronization.

Prognostic value role of radiofrequency lesion size by cardiac magnetic resonance imaging on outcomes of ablation in patients with ischemic scar-related ventricular tachycardia: A single center pilot study.

Inadequate ablation lesion formation may be responsible for post-ablation ventricular tachycardia (VT) recurrences.We aimed to evaluate whether visualisation of radiofrequency (RF) lesion size by cardiac magnetic resonance imaging (CMR) has any role in predicting adequacy of lesion and in estimating outcome.Retrospective pilot studyNine consecutive patients (8 male, age 60 ±â€Š13 years) underwent ablation for sustained VT because of ischemic scar were evaluated for pre- and post-procedure scar tissue by CMR to characterize ablation lesions. Microvascular obstruction (MVO) surrounded by late gadolinium enhancement was defined as irreversible RF lesion. All patients were followed for at least 6 months for recurrences.Five of the patients had previous inferior myocardial infarction (MI), whereas remaining 4 had anterior MI. Acute procedural success, as defined by termination of the arrhythmia without recurrence in 30 minutes, was attained in all patients. Contrast enhancement and wall motion abnormality in presumed infarction area were confirmed by pre-ablation CMR images. MVO was detected at the reported ablation site in 6/9 patients, all arrhythmia- and symptom-free at median 24 months (range 8-38 months) follow-up. In remaining 3 patients who had VT recurrence (clinical VT in 2, sustain VT with a new morphology in 1), MVO was not detected despite achievement of acute procedural success. There was no correlation with pre-ablation scar size and clinical arrhythmia recurrence.CMR is a useful imaging modality to guide ablation procedures by detecting scar tissue. Additionally MVO seen by post-procedural imaging may be related to adequacy of RF ablation lesions and may correlate with clinical outcome.

Galectin-3: A Novel Biomarker Predicts Sudden Cardiac Death in Hypertrophic Cardiomyopathy.

BACKGROUND: Hypertrophic cardiomyopathy is a primary cardiac disease characterized by left ventricular hypertrophy, myocyte hypertrophy and irregularities and interstitial fibrosis in the absence of any cardiac or systemic diseases and may lead to sudden cardiac death (SCD). Galectin-3 is a ß-galactoside-binding lectin that has been associated with cardiac fibrosis and inflammation. In this study, we aimed to investigate the relationship between serum galectin-3 levels and the criteria for 5-year sudden death risk, recently defined in the European Society of Cardiology guidelines (2014), in patients with hypertrophic cardiomyopathy. MATERIALS AND METHODS: A total of 52 hypertrophic cardiomyopathy patients were enrolled in the study. Patients were questioned for sudden death risk predictors as outlined in the 2014 European Society of Cardiology guideline. A standardized clinical evaluation was carried out on the basis of previously described prognostic variables to calculate the 5-year risk of SCD. Blood samples were taken from all patients to measure serum galectin-3 levels. A statistical significance level of P < 0.05 was accepted in all tests. RESULTS: We found that there was a significant correlation between the estimated 5-year risk of SCD and serum levels of galectin-3. CONCLUSIONS: Galectin-3 may be an inexpensive and easily accessible parameter to predict arrhythmia risk. In addition, it can be used to determine antiarrhythmic prophylaxis as a predictor of an arrhythmia storm in implantable cardioverter defibrillator-implanted patients who are not available for magnetic resonance imaging.

[Atrial fibrillation in the elderly]. / Yaslilarda atriyal fibrilasyon.

The prevalence of atrial fibrillation increases dramatically with advancing age. Elderly adults with atrial fibrillation-even those with high bleeding risk- benefit from anticoagulation. The risk of ischemic stroke or systemic embolism was significantly lower with new direct oral anticoagulants (DOACs) than warfarin as was the risk of major bleeding and intracranial bleeding. Antiplatelet therapy should have a limited role for stroke prevention in elderly adults. Left atrial appendix occlusion may be a suitable alternative for those with contraindications to oral anticoagulants. For symptom management, it is likely that a strategy of lenient rate control is reasonable in elderly adults with atrial fibrillation. Rhythm control should be reserved for specific circumstances, in particular when symptoms cannot be managed using rate control. In appropriately selected elderly adults with symptomatic atrial fibrillation, catheter ablation may also be a useful strategy, with acceptable safety and efficacy based on limited data. A rhythm control strategy should not preclude anticoagulation.

Recovery of cardiomyopathy induced by ventricular premature beats of paraHisian origin after successful radiofrequency catheter ablation.

A 51-year-old male patient presented with frequent and symptomatic premature ventricular complexes (PVCs) that had induced cardiomyopathy. Radiofrequency (RF) catheter ablation of the origin of the PVCs was planned and the patient underwent electrophysiological study. During activation mapping, the earliest ventricular activation was identified at the His bundle region. Small His bundle electrogram recording by the distal ablation electrode during sinus rhythm revealed that the earliest ventricular activation during PVC preceded the QRS onset by 58 milliseconds. The PVCs were successfully eliminated without occurrence of atrioventricular block using incremental application of RF energy to the para-Hisian region. At the conclusion of a 5-month follow-up period, the patient remained asymptomatic and transthoracic echocardiography demonstrated an improvement in left ventricular ejection fraction.

Postpacing Interval During Right Ventricular Overdrive Pacing to Discriminate Supraventricular from Ventricular tachycardia.

INTRODUCTION: Failure to differentiate supraventricular from ventricular arrhythmias is the most frequent cause of inappropriate implantable cardioverter-defibrillator (ICD) therapies. We hypothesized that the postpacing interval (PPI) after overdrive right ventricular pacing may differentiate ventricular (VT) from supraventricular tachycardia (SVT) such as sinus tachycardia, atrial flutter and atrial tachycardia. This hypothesis is based on the entrainment maneuver. Reentrant tachycardia circuit for VTs would haveshorter distance to RV apex than SVTs have, and the conduction time between a ventricular pacing site and the tachycardia origin is expected to be shorter in VTs than in SVTs. METHODS: 220episodes from 38 patients with single chamber ICDs that RV overdrive pacing could not terminate or change the tachycardia cycle length (TCL) were retrospectively reviewed. Episodes were classified as VTs (n=115) and SVTs (n=105). TCLs, PPIs and PPI-TCL were compared between groups. RESULTS: The cycle length of VTs was shorter than SVTs (320.6±30.3 vs 366.5±40 ms, p=0.001). PPI and PPI-TCL of VTs were shorter than SVTs (504.7±128.3 vs 689.2±121.8 ms, p=0.001, 184±103 vs 322.6±106.6 ms, p=0.001; respectively). ROC curve analysis demonstrated a 525 ms cut-off value for PPI has 89% sensitivity and 57.4% specificity to predict inappropriate ICD therapies due to SVTs (AUC:0.852). Similarly, A PPI-TCL <195 ms favored VT as a diagnosis rather than SVT with a 90% sensitivity, and 51% specificity (AUC:0.838). CONCLUSION: Analyzing of PPI during overdrive pacing from RV apex may discriminate supraventricular from ventricular tachycardia. This criterion may have a potential role in implantable devices that use a single ventricular lead.

Peri-Infarction Zone as a Risk Marker for Patients With Postmyocardial Infarction.

INTRODUCTION: The role of contrast-enhanced (ce) cardiac magnetic resonance in risk stratification of patients with depressed left ventricle (LV) function is widely studied. In this study, we investigated the myocardial infarct size and characteristics by ce-magnetic resonance imaging (MRI) and its relationship with spontaneous ventricular arrhythmia occurrence during follow-up of in patients with mild LV systolic dysfunction and nonsustained ventricular tachycardia (VT). MATERIALS AND METHODS: This study enrolled 32 patients with postmyocardial infarction with an LV ejection fraction between 40% and 50% and nonsustained VT. Cardiac MRI performed to identify cardiac scar size and characteristics. Dense scar, peri-infarction zone and total infarct masses were calculated, these values to LV mass ratios were obtained. All patients were followed up 48 ± 6 months. Cardiac magnetic resonance data compared among patients with (n = 6) and without spontaneous sustained VT (n = 26). RESULTS: During follow-up, 6 patients experienced sustained VT (VT+ group), whereas 26 patients had no sustained ventricular arrhythmia (VT- group). The groups had similar baseline clinical characteristics. The LV masses, volumes and ejection fractions did not differ significantly between 2 groups. For the VT+ group versus VT- group dense scar to LV mass were similar (3.1 ± 0.3% versus 3.3 ± 0.9%, P = not significant). Ratio of peri-infarction zone to LV mass (30.9 ± 6.1% versus 21.3 ± 7.5%, P = 0.007) and total infarct to LV mass (34.1 ± 6.1% versus 24.6 ± 7.9%, P = 0.011) were larger in patients with sustained VT. CONCLUSIONS: This small study supports the potential utility of ce-MRI to identify patients with postmyocardial infarction prone to develop serious ventricular arrhythmias.

Distinguishing Right Ventricular Cardiomyopathy From Idiopathic Right Ventricular Outflow Tract Tachycardia with T-wave Alternans.

BACKGROUND: The 2 predominant etiologies of right ventricular tachycardia (VT) are arrhythmogenic right ventricular cardiomyopathy (ARVC) and idiopathic VT arising from the right ventricular outflow tract. Discrimination between these 2 entities is critical, as their prognoses and therapeutic options differ. The microvolt T-wave alternans (TWA) is widely used to predict lethal ventricular arrhythmias in various diseases. However, the clinical significance of TWA in patients with VT originating from the right ventricle has been unknown. This study aims to investigate the possible role of TWA to discriminate ARVC from idiopathic right ventricular outflow tract tachycardia (RVOT-VT). METHODS: This study enrolled 38 patients (23 male, 43 ± 16 years) with VT originating from the right ventricle. TWA was measured during exercise testing using the modified moving average method. TWA results were compared among patients with ARVC and RVOT-VT. RESULTS: Twenty-five patients (16 male, 42 ± 16 years) met the Task Force criteria for the diagnosis of ARVC, and 13 patients (7 male, 45 ± 14 years) had idiopathic RVOT-VT. Twenty patients with ARVC had positive TWA test, whereas only 1 patient with RVOT-VT had (80% versus 8%, P < 0.001). CONCLUSIONS: In patients with VT of right ventricle origin, positive TWA test supports the diagnosis of ARVC.