Impact of Premature Ventricular Complex (PVC) Burden on the Left Ventricle in the Structurally Normal Heart: Hemodynamic Alterations of Idiopathic PVC on Echocardiography.

Background: Premature ventricular complex (PVC) without structural heart disease is mostly viewed as a benign arrhythmia. However, the high burden of PVC causes cardiomyopathy due to intraventricular dyssynchrony. The effects of ectopic contraction on left ventricular (LV) hemodynamics in the structurally normal heart are unclear. Objectives: To examine the effect of PVC burden on LV dimension, LV systolic function, and intraventricular blood flow, and to determine whether ectopic ventricular contraction affects LV hemodynamics. Methods: Patients aged ≥ 18 years with PVC ≥ 5% on Holter recording were enrolled and divided into groups G1 (5-10%), G2 (10-20%), and G3 (≥ 20%). We excluded patients with structural heart diseases, pacemakers, and LV systolic dysfunction [LV ejection fraction (LVEF) < 50%]. Clinical characteristics and routine transthoracic echocardiography parameters were compared. Results: The end-systolic LV internal dimension increased according to the PVC burden from G1 to G3 (p = 0.001). LVEF was inversely associated with PVC burden from G1 to G3 (p = 0.002). The same pattern was seen for LV outflow tract (LVOT) maximal velocity (p = 0.005) and maximal pressure gradient (PG) (p = 0.005), LVOT velocity time integral (VTI) (p = 0.03) and LV stroke volume index (LVSI) (p = 0.008). Conclusions: Systolic function and LV end-systolic dimension were inversely associated with PVC burden. Decreased LVOT flow velocity and PG were related to increased PVC burden. LVOT VTI and LVSI were smaller when the PVC burden exceeded 20%. These negative hemodynamic manifestations of idiopathic PVC were considerable even in structure normal hearts, hence the early elimination of PVC is strongly advised.

Severe Metabolic Acidosis and Hyperammonemia Induced by the Concomitant Use of Acetazolamide and Aspirin in a Patient With Impaired Renal Function.

BACKGROUND: Acetazolamide is contraindicated in patients undergoing dialysis and should be used with caution in patients with chronic kidney disease (CKD). Here, we evaluate the effect of the concomitant use of aspirin by patient with CKD using acetazolamide. CASE REPORT: A 63-year-old man with CKD and multimorbidity presented at our Emergency Department (ED) with general weakness and dyspnea for 4 days. Work-up at the ED revealed severe metabolic acidosis and hyperammonemia, which were initially considered signs of sepsis due to an elevated C-reactive protein level and pyuria. However, subsequent blood work indicated hyperchloremic acidosis with low lactate levels. After reviewing his medical history, we suspected the concomitant use of acetazolamide and aspirin as the etiology. Weakness, acidosis, and hyperammonemia were resolved after the patient discontinued acetazolamide. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Severe acidosis can be life threatening. Acetazolamide is known for causing mild metabolic acidosis, except in patients with severely impaired renal function. Here, we present a patient with mildly impaired renal function and concomitant aspirin use who developed severe metabolic acidosis and hyperammonemia after being prescribed acetazolamide. Regardless of the severity of the disease, patients with CKD should avoid taking acetazolamide concomitantly with aspirin.

Three-Dimensional Echocardiographic Assessment of Mitral Annular Physiology in Patients With Degenerative Mitral Valve Regurgitation Undergoing Surgical Repair: Comparison between Early- and Late-Stage Severe Mitral Regurgitation.

BACKGROUND: Ventricular-annular decoupling is thought to exist in all degenerative myxomatous mitral valve (MV) diseases. However, the annular physiology of degenerative MV disease may differ when severe mitral regurgitation (MR) presents at different stages. The aim of this study was to assess differences in mitral annular physiology and surgical effects between early- and late-stage severe MR. METHODS: Three-dimensional (3D) transesophageal echocardiography was performed before and after MV surgery in 74 patients with degenerative MV disease, including 57 with early-stage severe MR (without left ventricular remodeling) and 17 with late-stage MR (with left ventricular remodeling). A control group comprised 46 patients without MV disease. Novel 3D MV software was used to evaluate mitral annular dynamics. The degree of annular saddle shape was calculated as the ratio of annular height (AH) to lateromedial diameter (LM). Ventricular-annular decoupling was defined as insufficient systolic AH/LM compared with the control group. RESULTS: Prebypass 3D measurements demonstrated that systolic AH/LM in the early-stage group (0.19 ± 0.04) was similar to that in the control group (0.21 ± 0.05; P = .101), while systolic AH/LM in the late-stage group (0.17 ± 0.04) was lower than that in the control group (P = .011). Postbypass comparison showed saddle shape accentuation in the early-stage group (0.20 ± 0.04), similar to that in the control group (P = .3127); the mitral annulus remained flat in the late-stage group (0.17 ± 0.03; P = .004). CONCLUSIONS: Ventricular-annular decoupling, present in the late-stage group, was absent in the early-stage group. MV repair surgery did not disrupt mitral annular saddle shape in the early-stage group; however, it failed to correct annular dysfunction in the late-stage group. Sequential 3D transesophageal echocardiographic analysis provides comprehensive mitral annular evaluation beyond conventional two-dimensional parameters for determining stages of severe MR.

S1 and S2 Heart Sound Recognition Using Deep Neural Networks.

OBJECTIVE: This study focuses on the first (S1) and second (S2) heart sound recognition based only on acoustic characteristics; the assumptions of the individual durations of S1 and S2 and time intervals of S1-S2 and S2-S1 are not involved in the recognition process. The main objective is to investigate whether reliable S1 and S2 recognition performance can still be attained under situations where the duration and interval information might not be accessible. METHODS: A deep neural network (DNN) method is proposed for recognizing S1 and S2 heart sounds. In the proposed method, heart sound signals are first converted into a sequence of Mel-frequency cepstral coefficients (MFCCs). The K-means algorithm is applied to cluster MFCC features into two groups to refine their representation and discriminative capability. The refined features are then fed to a DNN classifier to perform S1 and S2 recognition. We conducted experiments using actual heart sound signals recorded using an electronic stethoscope. Precision, recall, F-measure, and accuracy are used as the evaluation metrics. RESULTS: The proposed DNN-based method can achieve high precision, recall, and F-measure scores with more than 91% accuracy rate. CONCLUSION: The DNN classifier provides higher evaluation scores compared with other well-known pattern classification methods. SIGNIFICANCE: The proposed DNN-based method can achieve reliable S1 and S2 recognition performance based on acoustic characteristics without using an ECG reference or incorporating the assumptions of the individual durations of S1 and S2 and time intervals of S1-S2 and S2-S1.

Critical care ultrasonography differentiates ARDS, pulmonary edema, and other causes in the early course of acute hypoxemic respiratory failure.

BACKGROUND: Pathogenic causes of acute hypoxemic respiratory failure (AHRF) can be difficult to identify at early clinical presentation. We evaluated the diagnostic utility of combined cardiac and thoracic critical care ultrasonography (CCUS). METHODS: Adult patients in the ICU were prospectively enrolled from January through September 2010 with a Pao2/Fio2 ratio < 300 on arterial blood gas (ABG) analysis within 6 h of a new hypoxemic event or the ICU admission. Focused cardiac and thoracic CCUS was conducted within 6 h of ABG testing. Causes of AHRF were categorized into cardiogenic pulmonary edema (CPE), ARDS, and miscellaneous causes after reviewing the hospitalization course in electronic medical records. RESULTS: One hundred thirty-four patients were enrolled (median Pao2/Fio2 ratio, 191; interquartile range, 122-253). Fifty-nine patients (44%) received a diagnosis of CPE; 42 (31%), ARDS; and 33 (25%), miscellaneous cause. Analysis of CCUS findings showed that a low B-line ratio (proportion of chest zones with positive B-lines relative to all zones examined) was predictive of miscellaneous cause vs CPE or ARDS (receiver operating characteristic area under the curve [AUC], 0.82; 95% CI, 0.75-0.88). For further differentiation of CPE from ARDS, left-sided pleural effusion (> 20 mm), moderately or severely decreased left ventricular function, and a large inferior vena cava minimal diameter (> 23 mm) were predictive of CPE (AUC, 0.79; 95% CI, 0.70-0.87). CONCLUSIONS: Combined cardiac and thoracic CCUS assists in early bedside differential diagnosis of ARDS, CPE, and other causes of AHRF.

Three-dimensional color Doppler echocardiographic quantification of tricuspid regurgitation orifice area: comparison with conventional two-dimensional measures.

BACKGROUND: Three-dimensional (3D) color Doppler echocardiography (CDE) provides directly measured vena contracta area (VCA). However, a large comprehensive 3D color Doppler echocardiographic study with sufficiently severe tricuspid regurgitation (TR) to verify its value in determining TR severity in comparison with conventional quantitative and semiquantitative two-dimensional (2D) parameters has not been previously conducted. The aim of this study was to examine the utility and feasibility of directly measured VCA by 3D transthoracic CDE, its correlation with 2D echocardiographic measurements of TR, and its ability to determine severe TR. METHODS: Ninety-two patients with mild or greater TR prospectively underwent 2D and 3D transthoracic echocardiography. Two-dimensional evaluation of TR severity included the ratio of jet area to right atrial area, vena contracta width, and quantification of effective regurgitant orifice area using the flow convergence method. Full-volume breath-hold 3D color data sets of TR were obtained using a real-time 3D echocardiography system. VCA was directly measured by 3D-guided direct planimetry of the color jet. Subgroup analysis included the presence of a pacemaker, eccentricity of the TR jet, ellipticity of the orifice shape, underlying TR mechanism, and baseline rhythm. RESULTS: Three-dimensional VCA correlated well with effective regurgitant orifice area (r = 0.62, P < .0001), moderately with vena contracta width (r = 0.42, P < .0001), and weakly with jet area/right atrial area ratio. Subgroup analysis comparing 3D VCA with 2D effective regurgitant orifice area demonstrated excellent correlation for organic TR (r = 0.86, P < .0001), regular rhythm (r = 0.78, P < .0001), and circular orifice (r = 0.72, P < .0001) but poor correlation in atrial fibrillation rhythm (r = 0.23, P = .0033). Receiver operating characteristic curve analysis for 3D VCA demonstrated good accuracy for severe TR determination. CONCLUSIONS: Three-dimensional VCA measurement is feasible and obtainable in the majority of patients with mild or greater TR. Three-dimensional VCA measurement is also feasible in patients with atrial fibrillation but performed poorly even with <20% cycle length variation. Three-dimensional VCA has good cutoff accuracy in determining severe TR. This simple, straightforward 3D color Doppler measurement shows promise as an alternative for the quantification of TR.

Prognostic significance of reciprocal ST-segment depression in patients with acute STEMI undergoing immediate invasive intervention.

PURPOSES: Reciprocal changes are frequent in patients with acute ST-segment elevation myocardial infarction (STEMI). However, their prognostic significance is not clear in patients undergoing immediate invasive intervention. BASIC PROCEDURE: We retrospectively examined 165 consecutive patients with STEMI receiving immediate invasive intervention. The first electrocardiography taken in the emergency department was analyzed. Patients were assigned to 2 groups: with a reciprocal change (group I, n = 100) and without a reciprocal change (group II, n = 65). MAIN FINDINGS: Electrocardiographs revealed that more anterolateral and inferior STEMI occurred in group I and more anterior STEMI occurred in group II. In the emergency department, group I had lower systolic and diastolic blood pressures, higher ventricular tachycardia and fibrillation rates, and higher cardiopulmonary resuscitation rates than did group II. Upon admission, peak troponin I levels were significantly higher in group I, and more group I patients required intra-aortic balloon pumping support. This unstable hemodynamic condition in group I patients was reflected by their higher in-hospital mortality rate. Multivariate analysis showed that age (odds ratio [OR], 1.103; 95% confidence interval [CI], 1.022-1.190; P = .012), Killip class (OR, 2.785; 95% CI, 1.049-7.400; P = .040), and reciprocal change (OR, 9.553; 95% CI, 1.146-79.608; P = .037) remained as independent predictors of in-hospital mortality. Actuarial freedom from all-cause mortality was worse in group I (P = .046). PRINCIPAL CONCLUSIONS: The data suggest that patients with STEMI with reciprocal electrocardiographic changes have unstable hemodynamic status and poorer outcomes. Further prospective studies using a larger patient population are needed.

Implantable cardioverter defibrillator therapy: ten years experience in a medical center.

BACKGROUND: An implantable cardioverter defibrillator (ICD) is the therapy of choice for survivors of life-threatening ventricular tachyarrhythmias or sudden cardiac death. To date there is little data concerning the clinical features and outcome of ICD therapy among Taiwanese. This study identifies factors related to the outcome of ICD therapy over a ten-year period at this institution. METHODS: Forty-nine ICDs were implanted in 46 patients between August 1996 and January 2006. The mean follow-up duration was 32 +/- 21 months. Patient data, primary cardiac diagnosis, presenting cardiac arrhythmia, echocardiographic parameters, hemodynamic indexes, electrophysiologic findings, and follow-up observations were analyzed. The findings were compared to those of the Taiwan ICD Multicenter Registry (TIMR) Study and major secondary prevention ICD trials in the literature. RESULTS: The patients in this study were comparable to those of TIMR but were younger and had better left ventricular ejection fractions (LVEF) than those in Western countries. Furthermore, higher mortality on follow-up was observed in patients with any of the following: LVEF < 35%, New York Heart Association (NYHA) functional class III or IV, a left atrial dimension > or = 55 mm, a left ventricular end diastolic dimension > or = 75 mm, an end systolic dimension > or = 60 mm, triple vessel disease, a prior anterior myocardial infarction, and amiodarone or diuretic therapy. Patients with structural heart disease other than ischemic heart disease or dilated cardiomyopathy had higher event recurrence rates. CONCLUSION: Left ventricular function is a major determinant affecting the outcome in ICD recipients. Aggressive treatment for heart failure is warranted in these patients.

Electrocardiographic features of ventricular pacing lead in the middle cardiac vein vs. right ventricular apex in a patient with persistent left superior vena cava.

A 53-year-old woman with sinus node dysfunction underwent dual-chamber pacemaker implantation through a persistent left superior vena cava draining into the coronary sinus, which was detected at the time of implantation. We managed to fix the ventricular lead in the right ventricular (RV) apex by forming a clockwise loop in the right atrium. Inadvertently, the lead was placed in the middle cardiac vein resembling RV apical position under fluoroscopic guidance. The paced QRS complex showed a pattern of tall R in V(1) through V(3), RS in V(4) through V(5), and QS in V(6). The pacing lead was carefully manipulated back into the RV apex, with the paced QRS complex showing a pattern of right bundle branch block, rR' in V(1) through V(2), and QS in V(3) through V(6). Careful attention to the surface electrocardiogram helps in distinguishing the pacing site even in those patients showing a pseudo-right bundle branch block pattern with RV apical pacing.

Entrapment of permanent pacemaker lead as the cause of tricuspid regurgitation.

Transthoracic 2-dimensional (D) echocardiography (echo) is often used to assess tricuspid regurgitation (TR) after implantation of permanent pacemakers. However, its ability to define the precise anatomical relationship between the tricuspid valve and the pacemaker lead is quite limited. This report presents a 58-year-old male with aggravation of TR after pacemaker implantation for heart block. Three-D echo precisely depicted the entrapment of the lead shaft in the fused and fibrotic septal and posterior tricuspid leaflets. The patient underwent tricuspid valve annuloplasty and the symptoms of right heart failure improved soon after the operation.