Correlation of echocardiographic left atrial abnormality with myocardial ischemia during myocardial perfusion assessment in the presence of known left ventricular hypertrophy.

Left atrial (LA) abnormality, an easily quantifiable parameter of left ventricular (LV) diastolic dysfunction, has been associated with cardiovascular risk similar to that of LV hypertrophy. The correlation between LV hypertrophy and LA abnormality among patients undergoing myocardial perfusion (MP) study has not been described. We prospectively studied 78 consecutive patients with LV hypertrophy who underwent MP study after screening for electrocardiographic and echocardiographic LA abnormality over a 6-month period. Of those, 48 had a positive MP imaging result, and 30 did not. LA size (p = 0.002) and P-wave duration (p = 0.017) were significantly increased in the former. The differential change in LA size (no defect = 35 ± 4, mild = 36 ± 5, moderate = 38 ± 5, severe = 44 ± 5 mm; p <0.0001) and P-wave duration (no defect = 107 ± 14, mild = 110 ± 17, moderate = 113 ± 15, severe = 127 ± 22 ms; p = 0.003) was greatest when the MP study defect exceeded moderate severity. In conclusion, the presence of LA abnormality could assist during MP study interpretation among patients with LV hypertrophy when such markers appear to be correlated with the severity of the MP study defect.

Correlation of echocardiographic left atrial abnormality with myocardial ischemia during myocardial perfusion assessment in patients with left bundle branch block.

Left atrial (LA) abnormality, an easily quantifiable parameter of left ventricular (LV) diastolic dysfunction, has been associated with cardiovascular risk. Because during myocardial perfusion study (MPS), the abnormal LV activation pattern in patients with left bundle branch block (LBBB) frequently induces perfusion defects, a clinical correlate of early myocardial ischemia such as LA enlargement could alleviate some of these inherent challenges. We prospectively studied 144 consecutive patients with LBBB who underwent MPS after screening for electrocardiographic and echocardiographic LA enlargement over a 6-month period. Of those, 114 had a positive MPS result. We found that LA size (p <0.0001) and P-wave duration (p = 0.001) were significantly increased in patients as the severity of the defects increased on MPS, whereas LV ejection fraction was decrementally reduced (p = 0.001). Importantly, LA size (≥43.5 mm; sensitivity 70%, specificity 89%) and P-wave duration (≥135 milliseconds; sensitivity 63%, specificity 90%) were greatest when the MPS defect was severe. In conclusion, the presence of LA enlargement appears significantly correlated with myocardial ischemia among patients with LBBB and could therefore assist during MPS interpretation among patients in whom MPS interpretation could be challenging.

The presence of ST-elevation in lead aVR predicts significant left main coronary artery stenosis in cardiogenic shock resulting from myocardial infarction: the Manitoba cardiogenic shock registry.

INTRODUCTION: Electrocardiographic (ECG) predictors of significant angiographic left main coronary artery stenosis (LMCS>50%) have been described in acute myocardial infarction using ST-segment elevation in lead aVR (aVR-STE). However, there is a paucity of data on its association with LMCS>50% in the setting of cardiogemic shock (CGS). METHODS: We investigated 210 consecutive, unselected, patients from Sept. 2002-2006 with CGS due to acute myocardial infarction undergoing cardiac catheterization. Of those, 191 patients with interpretable ECG tracings for aVR-STE analysis formed our study sample. aVR-STE was defined as ST-segment elevation≥1mm in aVR while LMCS>50% on coronary angiogram was defined as any left main lesion that demonstrated >50% lumen narrowing or equivalent by direct visualization or quantitative coronary angiography analysis. RESULTS: There was 59% survival to discharge of this predominantly male cohort (median age 68±12years; 31% females). Fifty three (28%) cases had aVR-STE while 27 (14%) had LMCS>50%. Of those, 16 patients who had aVR-STE also had LMCS>50% (sensitivity 59%, specificity 77%, positive predictive value 30%, negative predictive value 92% for predicting LMCS>50%). Multivariate analysis revealed that aVR-STE was the only significant predictor of LMCS>50% was (p=0.014; Odds Ratio=3.06; 95% Confidence Interval 1.26-7.47). CONCLUSION: In CGS due to acute myocardial infarction, aVR-STE>1mm proves to be an important predictor of LMCS>50%. Such data could be helpful in further risk stratification for optimal management during CGS.

Atrial Fibrillation in Patients with Ischemic and Non-Ischemic Left Ventricular Dysfunction.

Atrial fibrillation (AF) and left ventricular dysfunction (LVD) are increasingly common clinical problems, affecting millions of people worldwide. It is well established that the presence of AF portends a poor prognosis in the setting of both ischemic and non-ischemic LVD, and frequently results in worsening clinical status. Many clinical studies and trials have attempted to address treatment options and efficacy; despite this treatment for AF in LVD is still controversial.

Usefulness of diastolic time measured on electrocardiogram to improve sensitivity and specificity of exercise tolerance tests.

The current exercise tolerance test (ETT) criteria predominantly assess changes in ST-segment deviation (i.e., a systolic component of the cardiac cycle). Because diastolic dysfunction precedes that of systolic dysfunction during myocardial ischemia and most coronary flow is diastolic, the addition of electrocardiographic markers of diastolic time might improve the ETT sensitivity and specificity for detecting significant coronary artery disease. Among consecutive patients who had an ETT and subsequently underwent coronary angiography, we evaluated the diastolic time by assessing the TP and TQ segments and TP/RR and TQ/RR ratios in each ETT stage. Coronary artery disease was defined angiographically as significant (≥70% lumen occlusion), intermediate (>50% but <70% lumen occlusion), or nonsignificant (≤50% lumen occlusion). Of the 48 study patients, hypertension and hyperlipidemia appeared highly prevalent. TP, TQ, TP/RR, and TQ/RR correlated significantly with RR and changed with each ETT stage. Although TP and TQ were not significantly associated with significant coronary artery disease, TP/RR and TQ/RR proved to be, particularly beyond stage 2. When TQ/RR of ≤0.39 and TP/RR of ≤0.13 were used, their individual sensitivities and specificities were reasonably comparable to that of traditional ETT criteria (79% sensitivity and 44% specificity at our institution). Adding TQ/RR of ≤0.39 and/or TP/RR of ≤0.13 to existing ETT criteria improved its sensitivity to 100% and specificity to 86%. In conclusion, the addition of diastolic time indexes of TP/RR and TQ/RR significantly improved the overall ETT diagnostic value above the guideline-oriented, perhaps "traditional," criteria for the diagnosis of myocardial ischemia. Such parameters should be widely investigated further for clinical accuracy and compatibility.

Left atrial passive emptying function during dobutamine stress MR imaging is a predictor of cardiac events in patients with suspected myocardial ischemia.

OBJECTIVES: The aim of this study was to determine the prognostic value of assessing left atrial function during dobutamine stress testing. BACKGROUND: Left ventricular diastolic dysfunction precedes systolic wall motion abnormalities in the ischemic cascade. Severity of left ventricular diastolic function during cardiac stress is not characterized well by current clinical imaging protocols but may be an important prognostic factor. We hypothesized that abnormal early left atrial emptying measured during dobutamine stress cardiac magnetic resonance will reflect these diastolic changes and may be associated with cardiovascular outcomes. METHODS: We enrolled 122 consecutive patients referred for dobutamine stress cardiac magnetic resonance for suspected myocardial ischemia. Left atrial volumes were retrospectively measured by the biplane area-length method at left ventricular end-systole (VOL(max)) and before atrial contraction (VOL(bac)). Left atrial passive emptying fraction defined by (VOL(max) - VOL(bac)) × 100%/VOL(max) and the absolute percent increase in left atrial passive emptying fraction during dobutamine stress (ΔLAPEF) were quantified. RESULTS: Twenty-nine major adverse cardiac events (MACE) occurred during follow-up (median 23 months). By Kaplan-Meier analysis, patients with ΔLAPEF <10.8 (median) experienced higher incidence of MACE than did patients with a ΔLAPEF >10.8 (p = 0.004). By univariable analysis, ΔLAPEF was strongly associated with MACE (unadjusted hazard ratio for every 10% decrease = 1.56, p < 0.005). By multivariable analysis, every 10% decrease in ΔLAPEF carried a 57% increase in MACE, after adjustment to presence of myocardial ischemia and infarction. CONCLUSIONS: Reduced augmentation of left atrial passive emptying fraction during dobutamine stress demonstrated strong association with MACE. We speculate that reduced left atrial passive emptying reserve during inotropic stress may represent underlying diastolic dysfunction and warrants further investigation.

Cardiovascular magnetic resonance in mild to moderate clozapine-induced myocarditis: is there a role in the absence of electrocardiographic and echocardiographic abnormalities?

Clozapine is an atypical, neuroleptic medication that can cause myocarditis. While the "gold standard" for diagnosis of myocarditis is perceived to be via myocardial biopsy, cardiovascular magnetic resonance (CMR) has also proven its utility in this respect, primarily through its ability to detect myocardial scar by late-gadolinium enhancement (LGE). Until recently, however, clozapine-induced myocarditis specifically has not been known to be associated with LGE on CMR. In that particular case, LGE was demonstrated in a patient with clozapine-induced myocarditis. However, quite important, that patient also had specific abnormalities on the electrocardiogram (ECG) and echocardiogram that corresponded to the area of LGE demonstrated by CMR. We highlight a case series of three patients with clozapine-induced myocarditis and provide a literature review to discuss and critically appraise the true incremental diagnostic value of CMR in such patients with normal ECG and echocardiography.

Progression of low-pressure to acute classic cardiac tamponade-a diagnostic dilemma in the setting of spontaneous left ventricular rupture.

Cardiac tamponade (CT) is a pathophysiologic continuum where hemodynamic embarrassment occurs as a result of progressive, decreased venous return that impairs diastolic ventricular filling, which in turn, when uncorrected, severely compromises cardiac output. While CT is classically associated with high intrapericardial pressures due to rapidly accumulating large pericardial effusions, low-pressure CT is a recognized entity in which a comparatively low intrapericardial pressure could result in cardiac chamber compression and subsequent cardiovascular collapse. In this article, we highlight a previously unreported scenario of rapidly re-accumulating, acute CT in the setting of left ventricular rupture in a patient who had presumably presented with low-pressure CT due to hemoperiardium.

Myocardial siderosis due to hemochromatosis in an individual with hypertrophic cardiomyopathy.

A patient with hypertrophic cardiomyopathy (HCM) and transfusion-dependent sideroblastic anemia, who presented with decompensated heart failure, is described. The present case demonstrates the usefulness of cardiac magnetic resonance imaging as a noninvasive imaging modality to assess the etiology of new systolic dysfunction in the setting of HCM. Cardiac magnetic resonance imaging is able to differentiate between the dilated 'burned-out' phase of HCM and a concomitant dilated cardiomyopathy secondary to myocarditis or hemosiderosis.

Is there a role for statins in atrial fibrillation?

3-Hydroxy-3-methyl-glutaryl-CoA reductase inhibitors (statins) are some of the most commonly prescribed drugs in the world. While lipid modification remains the primary function of statins, there has been increasing interest in its potential pleiotropic effects, particularly as an anti-inflammatory agent in its role as an antiarrhythmic. Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice and carries with it a significant burden in both morbidity and mortality. Treatment for AF currently involves either rate or rhythm control where both have demonstrable associated risks. Rate control necessitates anticoagulation, which can cause life-threatening bleeding, while rhythm control has a poor side-effect profile that may lead to greater mortality and may not completely eliminate the need for anticoagulation. Considering this pressing need for novel therapeutic interventions in AF, this long overdue systematic review explores the potential role of statins in the treatment and prevention of AF. Physicians, especially cardiologists, need to be aware of the host of currently available literature and, more importantly, need to be stimulated to generate discussion and formulate studies that will help debate the issues under the most erudite standards.

Utility of the frontal plane QRS axis in identifying non-ST-elevation myocardial infarction in patients with poor R-wave progression.

Poor R-wave progression (PRWP) is a common electrocardiographic phenomenon in which the anticipated increase in R-wave amplitude in successive precordial leads, V(1) to V(5), fails to occur. PRWP is prevalent in approximately 10% of hospitalized adult patients, predominantly in those with coronary artery disease. Debate is ongoing on its association with myocardial infarction (MI). However, studies that showed no association failed to appraise the significance of the QRS axis in relation to PRWP among such patients with MI. In our retrospective study, we consecutively identified 150 unselected adult patients with PRWP among 660 successive admissions to the general medical floors of a tertiary care teaching hospital (Saint Vincent Hospital, Worcester, Massachusetts). After excluding patients with anterior wall Q-wave MI (defined as the presence of a QS complex or Q-wave > or =1 mm deep in V(2) or V(3)), sudden unexpected death, MI after percutaneous coronary interventions or coronary artery bypass grafting during this hospitalization, Wolff-Parkinson-White syndrome, pacemakers, bundle branch blocks, and electrocardiograms that were of poor quality or affected by severe motion artifact, inconsistencies with patient identification, or errors in lead placement, 137 patients remained. The patients were then screened for non-ST-segment elevation MI (NSTEMI) during the present admission. The DePace criteria for PRWP were systematically used for all patients, and the QRS axis was calculated using limb leads based on Einthoven's equilateral triangle (normal was considered -30 degrees to 100 degrees ). Of the 137 study patients screened with PRWP, 38 had NSTEMI (25.3%). Thirty-one had a normal QRS axis (mean age +/- standard deviation 71.3 +/- 12 years), and 7 showed either right or left axis deviation (mean age +/- standard deviation 64.3 +/- 15 years). This proved to be statistically significant (p <0.0001) within this cohort of NSTEMI patients. In conclusion, PRWP determined using the DePace criteria in the presence of a normal QRS axis appears to be more significantly associated with the presence of overall MI within this cohort of NSTEMI patients.

Is the presence of mitral annular calcification associated with poor left atrial function?

INTRODUCTION: Mitral annular calcification (MAC) is characterized by calcium and lipid deposition in the annular fibrosa of the mitral valve. MAC is associated with cardiovascular events but little is known of its association with left atrial (LA) function. METHODS: We prospectively obtained 12-lead electrocardiograms (ECGs) and transthoracic echocardiograms (TTE) on patients scheduled for nonemergent echocardiographic assessment at a tertiary care hospital. MAC was graded as 0 = none, 1 = mild, 2 = moderate, 3 = severe. LA linear and volume measurements (stroke volume, LA passive emptying fraction, LA active emptying fraction and LA kinetic energy) were done specifically in addition to commonly measured TTE parameters. RESULTS: From the 124 considered for the study, 72 patients remained (aged 68+/-18 years; 44% male) after excluding those with poor ECG tracings and/or poor TTE images. Eighteen patients had MAC; mild MAC = 14, moderate MAC = 3, severe MAC = 1. When patients with MAC were compared to those without MAC, no significant difference was noted, except for LA linear dimension index (2.1+/-0.4 vs. 1.9+/-0.3 cm/m(2); P = 0.03). For those with mild and moderate MAC, a trend was noted toward lower LA function with increasing MAC severity. In addition, significant differences were noted between those with and without interatrial conduction delay, where those with such delay had significantly impaired LA stroke volume (9.8+/-3 vs. 19.93+/-4 ml; P < 0.0001), LA active emptying fraction (18.83+/-8 vs. 65.71+/-9%; P < 0.0001) and LA total/reservoir fraction (39.54+/-6 vs. 75.1+/-6%; P < 0.0001). CONCLUSIONS: MAC is associated with increase in LA linear dimension on TTE and may be equally represented with lower overall LA function. Further study in a much larger cohort is warranted to delineate these and other potential associations of MAC.

Interatrial block: the pandemic remains poorly perceived.

Interatrial block (IAB; P duration >or=110 ms) is a common electrocardiogram abnormality, which in addition to reduced left atrial function predicts atrial fibrillation and other arrhythmias. P terminal force (Ptf) +/- biphasic P in lead V(1)>or= the area of one small square on the grid also indicates left atrial abnormality, particularly left atrial enlargement, which is a strong correlate of IAB. Among 482 consecutively recorded electrocardiograms, IAB and Ptf were strongly and significantly correlated (chi(2)= 68.041; P

The utility of cardiovascular magnetic resonance in constrictive pericardial disease.

Cardiovascular magnetic resonance (CMR) has a high diagnostic accuracy for constrictive pericarditis (CP). CMR allows for high-resolution imaging of the pericardium and associated structures in any imaging plane compared with that provided by other imaging modalities. We briefly discuss the specific quantitative and qualitative CMR sequences that can be tailored to answer the clinical questions pertaining to CP, where the diagnostic yield has been proven when characteristic CMR features of CP are present. Such features allow for differentiation of CP from restrictive cardiomyopathy, where the clinical differentiation between the 2 can often be challenging.

Interatrial block: correlation with P-terminal force.

BACKGROUND AND HYPOTHESIS: Interatrial block (IAB: P-duration > 100 ms) is poorly recognized in hospital populations. In addition to reduced left atrial function and left atrial enlargement it predicts atrial fibrillation and other arrthymias. P-terminal force (Ptf): +/- biphasic P in lead V(1) > or = area of 1 small square on the electrocardiogram (ECG) grid also indicates left atrial abnormality, particularly left atrial enlargement. These 2 should be related. We determined the intercorrelation. METHODS AND RESULTS: Two blinded observers evaluated 500 consecutive patients' ECGs for both Ptf and IAB utilizing all 12 leads for IAB and V(1) for Ptf. Measurement differences were resolved in a consensus conference. Among 482 usable ECGs, IAB and Ptf were strongly and significantly correlated (chi(2) = 68.041; P < or = .001). CONCLUSION: IAB and Ptf are significantly and strongly correlated and one should be expected in the majority of cases when the other is recognized.

Prospective assessment of cardiovascular events in patients with partial and advanced interatrial conduction delay: a preliminary observation.

INTRODUCTION: Major adverse cardiovascular events (MACE) have been investigated with partial interatrial block (IAB; P wave > or = 110 ms) but not with advanced IAB. METHODS: Twenty-four advanced IAB and 34 partial IAB patients were followed for 24 months for MACE, change in renal function and death. RESULTS: Three patients with advanced IAB had myocardial infarction compared to none with partial IAB (p = 0.03). However, overall MACE was not significantly different between groups with an overall low event rate. There was also no difference between change in mean blood urea nitrogen levels and calculated glomerular filtration rates over time. CONCLUSION: In a preliminary 24-month period, when compared to patients with partial IAB, those with the uncommon, advanced form of IAB do not appear to be overly at increased risk for MACE. However, larger prospective studies are needed to confirm these results in order to appraise other cardiovascular risk factors.

The association of atrial tachyarrhythmias with isolated atrial amyloid disease: preliminary observations in autopsied heart specimens.

OBJECTIVE: Isolated atrial amyloidosis (IAA) is associated with atrial tachyarrhythmias. However, only a few studies have appraised atrial tachyarrhythmias and atrial depolarization abnormalities in connection with high-grade IAA. We conducted a collaborative retrospective study to assess this association. METHODS: One hundred consecutive autopsied hearts were studied histologically for IAA. To increase the specificity for atrial depolarization abnormalities in this preliminary study, we excluded those specimens with intermediate amyloid involvement, i.e. IAA grades 1 and 2 (grade 0 = absent or trivial deposits; grade 1 = small deposits; grade 2 = moderate deposits; grade 3 = dense, large deposits). We then screened for baseline, premortem electrocardiograms (ECGs) to assess rhythm. In those with sinus rhythm, the P wave axis, duration, dispersion and terminal force in V1 were determined under magnification. RESULTS: Of the 27 premortem ECGs corresponding to the autopsy specimens with grades 3 (sample) or 0 (controls) IAA, 9 showed sinus rhythm, 13 showed atrial fibrillation, 1 showed atrial flutter and 4 were uninterpretable. Fourteen autopsied hearts (52%) were positive for grade 3 IAA. Ten of those had atrial tachyarrhythmias (9 atrial fibrillation and 1 atrial flutter) compared to 4 of the 13 hearts with grade 0 IAA (72 vs. 31%, respectively; p = 0.03). Although there was excellent interobserver agreement using intraclass correlation coefficients, there were no significant differences in P wave measurements among the small number of patients with sinus rhythm for grade 3 versus grade 0 IAA. CONCLUSION: In a collaborative, preliminary, pilot assessment of autopsied hearts for which premortem ECGs were necessarily screened retrospectively, significantly more hearts with high-grade IAA were associated with atrial tachyarrhythmias compared to those with low-grade IAA. A larger study with an appropriately matched autopsy control group is needed to confirm these and previous observations.

Formulaic quantification of echocardiographic left atrial volume.

INTRODUCTION: The association between increasing severity in abnormal atrial depolarization and left atrial (LA) volume derived by transthoracic echocardiogram (TTE) has been described through the following regression formula: LA end-systolic volume index (LAVI [milliliter]) = 8.0 + 0.2 (P-wave duration [millisecond]) (r = 0.47; P = .0002). However, prospective assessment of this formula has not been validated among inpatients outside the institution where it was first derived. METHODS: We prospectively obtained 12-lead electrocardiograms (ECGs) and TTEs on consecutive inpatients who were scheduled for nonemergent echocardiographic assessment. P waves were assessed independently to the nearest 10 milliseconds for application of the formula with a Bland-Altman plot. P-wave durations were obtained specifically from lead II and also from the any lead that yielded the widest measurement. RESULTS: After excluding those with poor ECG tracing and TTE images, 72 patients were studied. We found a strong formulaic correlation with LAVI by TTE when maximal P-wave measurements were obtained from any ECG lead (r = 0.67; P < .0001) and more so, when restricted only to lead II (r = 0.89; P < .0001). Correlation was strongest when there was no or minimal difference between P-wave measurements in lead II and all other leads (r = 0.84; P < .0001 for no difference vs r = 0.67; P < .0001 for 60-millisecond difference). The Bland-Altman plot showed good agreement of LAVI assessment using the formulaic estimation when compared to TTE measurements derived by Simpson's rule (coefficient of reproducibility for 2 SD equivalent to 8.8% for lead II and 11.4% for any lead). CONCLUSION: There is good agreement and correlation between formulaic estimation and that of TTE for LAVI among inpatients. Such quantification of LA size not only serves as an indirect asset that could perhaps supplement TTE measurements in certain circumstances but also can facilitate risk stratification of patients.

Electrocardiographic criteria in tako-tsubo cardiomyopathy-is there added certainty in a diagnosis per exclusionem?

Tako-Tsubo cardiomypathy (TTC), also known as transient left ventricular apical ballooning syndrome, is a stress-induced cardiomyopathy that predominantly affects post-menopausal, elderly women during emotional or physical stress. Apical left ventricular dysfunction in the absence of significant coronary artery disease is the hallmark of this condition. Because the electrocardiogram (ECG) classically depicts precordial ST-segment elevations and cardiac biomarkers can often be raised, it can be a challenge to differentiate TTC from an acute myocardial infarction (AMI). Indeed, several recent studies have proposed ECG criteria to differentiate TTC from an AMI. We present a case series of consecutive patients in whom we had employed such ECG criteria but were unable to conclusively differentiate TTC from an AMI. In each case, TTC remained a diagnosis per exclusionem, where coronary angiography was necessary to rule out myocardial infarction. We review and discuss the commonly used ECG criteria and highlight the evolutionary ECG changes commonly noted with TTC to help better prepare clinicians when dealing with patients with similar clinical scenarios.