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The case of a 45-year-old man suffering from a catecholamine-sensitive ventricular tachycardia originating from the right ventricular outflow tract is reported. The authors describe a novel noninvasive treatment strategy for the management of this patient. [ABSTRACT FROM AUTHOR]

The objective of this study was to assess the feasibility of DDD pacing from a standard singlepass VDD pacemaker system. Over the past 2 decades significant advances have been made in the development of single-pass VDD pacing systems. These have been shown in long-term prospective studies to effectively preserve atrioventricular (AV) synchrony in patients with AV block and normal sinus node function. What remains problematic is the development of a single-pass pacing system capable of DDD pacing, Such a lead configuration would be useful in those patients with peripheral venous anomalies and in younger patients with congenital anomalies, which may require lead revisions in the future. In addition, with the increased use of resynchronization (biventricular pacing) therapy, the availability of a reliable single-pass lead will minimize operative time, enhance patient safety, and minimize the amount of hardware within the heart. The feasibility of DDD pacing via a Medtronic Capsure VDD-2 (Model #5038) pacing lead was evaluated. Twenty patients who presented with AV block and normal sinus node function were recruited for this study. Atrial pacing thresholds and sensitivities were assessed intraoperatively in the supine position with various respiratory maneuvers. Five patients who agreed to participate in long-term follow-up received a dual-chamber generator and were evaluated periodically over a 12-month period. Mean atrial sensitivity was 2.35 ±0.83 mV at the time of implantation. Effective atrial stimulation was possible in all patients at the time of implantation (mean stimulation threshold 3.08 ±1.04 V @ 0,5 ms [bipolar], 3.34 ±0.95 V @ 0.5 ms [unipolar]). Five of the 20 patients received a Kappa KDR701 generator, and atrial electrical properties were followed up over a 1 -year period. There was no significant change in atrial pacing threshold or incidence of phrenic nerve stimulation over the 1-year follow-up. A standard single-pass VDD pacing lead system was capable of DDD pacing intraoperatively and during long-term follow-up. Despite higher than usual thresholds via the atrial dipole, pacemaker telemetry revealed lt; 10% use of atrial pacing dipole over a 12-month period, which would minimally deplete the pacemaker's battery. In addition, the telemetry confirmed appropriate sensing and pacing of the atrial dipole throughout the study period. At this time such systems can serve as back-up DDD pacing systems with further refinements required to optimize atrial thresholds in all patients. [ABSTRACT FROM AUTHOR]

Transesophageal echocardiography is a useful adjunct to other diagnostic modalities in uncovering the etiology of congestive heart failure. The authors describe the case of a 75-year-old woman with a 4-week history of progressive congestive heart failure, in whom transesophageal echocardiography played a critical role in the diagnosis of a right atrial mass, accounting for this patient's constellation of symptoms. [ABSTRACT FROM AUTHOR]

Effects of Beta-Blockade and d-Sotalol on Reentry. Introduction: The importance of beta receptor blockade for the antiarrhythmic action of sotalol has not been completely elucidated. We determined how beta receptor blockade interacts with the effects of potassium channel blockade on reentrant circuits. Methods and Results: Sustained ventricular tachycardia was induced by programmed stimulation in dogs 4 days after left anterior coronary artery occlusion and reentrant circuits in the epicardial border zone (EBZ) mapped. The effects of the beta receptor-blocking drug, esmolol, the potassium channel-blocking drug d-sotalol, which lacks beta receptor-blocking effects, and the combination of the two drugs on the reentrant circuits that cause tachycardia were determined. Esmolol did not alter the ability to induce tachycardia. Small changes in the location or extent of lines of block in reentrant circuits accounted for small decreases or increases in tachycardia cycle lengths. d-Sotalol prolonged the lines of block in reentrant circuits, slowed propagation around the circuits, and prolonged tachycardia cycle length, but it did not stop tachycardia or prevent the induction of tachycardia. The combination of esmolol and d-sotalol prevented the initiation of sustained tachycardia. The stimulated premature impulse either blocked before reentering or traversed the circuit several times prior to blocking in a region of fractionated electrograms. The addition of esmolol to d-sotalol abolished the reverse use-dependent effects of d-sotalol alone on effective refractory period (ERP) and significantly prolonged ERP in the area of the reentrant circuit. Conclusion: Beta receptor blockade is important for the antiarrhythmic effects of d,l-sotalol on reentrant ventricular tachycardia in this model. The mechanism is speculative but may involve potentiation of d-sotalol actions to prolong ERP or effects on gap junctions. (J Cardiovasc Electrophysiol, Vol. 14, pp. 1233-1244, November 2003) [ABSTRACT FROM AUTHOR]

Most wide-complex tachycardias encountered in the emergency department (ED) are ventricular in origin, most commonly associated with structural heart disease. Ventricular tachyarrhythmias range in severity from life-threatening rhythms (eg, ventricular fibrillation and hemodynamically compromising ventricular tachycardia [VT]) to idiopathic forms of VT, which have a benign clinical course and a more favorable prognosis. The authors present the case of a 34-year-old woman who presented to the ED, with a wide-complex tachycardia with a rightbundle-branch block (RBBB) morphology and a right inferior axis, which was terminated with adenosine. The patient was previously misdiagnosed as suffering from a paroxysmal supraventricular tachycardia (SVT), which was unresponsive to beta-blocker therapy. Although the tachycardia responded to adenosine, suggestive of an SVT, the patient was referred to the arrhythmia service, where further work-up revealed an uncommon form of an idiopathic VT, originating from the left anterior fascicle. The authors discuss the unique electrocardiographic and electrophysiologic properties and useful diagnostic maneuvers required to properly identify this form of VT. [ABSTRACT FROM AUTHOR]

KASSOTIS, J., et al.: Effects of Angiotensin‐Converting Enzyme Inhibitor Therapy on QT Dispersion Post Acute Myocardial Infarction.The aim of this study was to determine the effect of an angiotensin‐converting enzyme inhibitor (ACEI), initiated within 24 hours of an acute myocardial infarction (AMI), on the QT dispersion (QTd). ACEIs have proven beneficial in improving left ventricular remodeling, following an AMI while contributing to a reduction in sudden cardiac death (SCD). A prolonged QTd is a marker of electrical instability predisposing to ventricular arrhythmias and SCD. No one has looked at the effects on the QTd of ACEI therapy initiated within 24 hours of an AMI. The study included 239 consecutive patients who presented with an AMI between January 1, 1998 and December 31, 1998. A total of 105 patients had never been treated with an ACEI, and 51 patients were started on enalapril within 24 hours of presentation. Patient demographics were similar in both groups. All patients were treated with aspirin and β‐blocker therapy. A baseline QTd was determined and recalculated on days 3–4 and 6–7 following the AMI. There was no significant difference in the baseline QTd, heart rate, QTcmin, and QTcmax between the two groups. On days 3–4 the QTd in the treatment group (A) was39.2 ± 19.4 ms, as opposed to84.4 ± 31.2 msin the control group (B) (P = 1.0E‐06). This reduction in QTd was accounted for by a significant difference in the QTcmax. The QTd shortened in both groups on days 6–7 with a QTd of30.0 ± 17.5in group A and a QTd of54.1 ± 26.3in group B(P = 1.0E‐05). There was a significant difference in ejection fraction (EF) between the two groups with the ACEI treated group exhibiting a lower EF, (0.403 (A), 0.494 (B),P < 0.043). The mean dose of enalapril was 6.45 mg daily in the treatment group. ACEIs have been previously shown to reduce the QTd after two months of therapy following an AMI. This study shows that the beneficial effects of ACEI occur early following administration of the drug. The authors speculate that the reduction in SCD conferred by ACEI therapy may be attributed to its effect on reducing the degree of ventricular dispersion of repolarization following a myocardial infarction. (PACE 2003; 26[Pt. I]:843–848) [ABSTRACT FROM AUTHOR]

Presents a case of an asymptomatic left ventricular lead malposition diagnosed upon routine 2-D Echocardiography. Clinical symptoms; Observation of a right bundle branch block pattern and a left-axis deviation using the 12-lead electrocardiography; International normalization ration after warfarin therapy.

No abstract available [ABSTRACT FROM AUTHOR]

The article highlights a 69-year-old woman with dyspnea, presenting with pleural plaques linked to asbestos exposure, developing constrictive pericarditis due to asbestosis, leading to a pericardiectomy with subsequent positive progress at a 2-year follow-up.

Transcatheter aortic valve replacement (TAVR) has emerged as a minimally invasive alternative to surgical aortic valve replacement (SAVR). However, racial disparities in the utilization of TAVR persist. This meta-analysis attempts to determine whether the prevalence of adverse outcomes (procedure-related complications) represent barriers to the use of TAVR among African Americans (AA). The TAVR cohort consisted of 89.6% Caucasian (C) and 4.7% AA, while the SAVR cohort included 86.9% C and 6.4% AA. The utilization rate (UR) of TAVR was 1.48 and.35 among C and AA, respectively, while the UR of SAVR was 1.44 and.48 among C and AA, respectively. Following TAVR, for AA the odds ratio (OR) was greater for stroke (OR = 1.22, P =.02) and transient ischemic attack (TIA) (OR = 1.57, P <.001) and lower for undergoing the insertion of a permanent pacemaker (OR =.81, P <.001). While there was a significant difference between C and AA in TAVR and SAVR utilization, outcomes between groups following TAVR are comparable; therefore, adverse outcomes do not appear to be a barrier to the use of TAVR among eligible AA. [ABSTRACT FROM AUTHOR]

The superiority of drug-eluting stents (DES) compared with bare-metal stents (BMS) is well-established, but data regarding DES use in ST-elevation myocardial infarction (STEMI) as a function of race is limited. Our goal was to examine stent utilization patterns and disparities based on race, sex, and insurance status in patients with STEMI undergoing percutaneous coronary intervention. The National Inpatient Sample database was used to retrospectively compare DES vs BMS use in patients admitted with STEMI from 2009 to 2018. Multivariable logistic regression was performed to assess the independent predictors of DES use. DES utilization increased significantly from 62.8% in 2009 to 94.0% in 2018. However, African Americans were less likely to receive a DES (odds ratio [OR].82, 95% confidence interval [CI].77–.87) compared with Caucasians. Women were more likely to undergo DES implantation (OR 1.07, 95% CI 1.05–1.10). Patients insured by Medicaid (OR.84, 95% CI.80–.89) and those classified as Self-pay (OR.63, 95% CI.61–.66) were less likely to undergo DES implantation compared to those with private insurance (OR 1.33, 95% CI 1.29–1.38). Disparities based on race and insurance status continue to persist despite a significant increase in DES utilization in STEMI patients across the identified subgroups. [ABSTRACT FROM AUTHOR]

Antibiotic use for cardiovascular implantable devices (CIED) prophylaxis is well-accepted despite a paucity of data. Pre-procedural prophylaxis lowers the rate of CIED infections; however, data is lacking for intra- or post-procedural antibiotic use. Antibiotic-eluting envelopes (ENVELOPE) [TYRX®TM] have been shown to reduce post-procedural infections. Understanding implanter practices may provide insight as to the need for antibiotic stewardship. The purpose of this survey was to assess the practices of implanters nationally. A survey was completed by 150 implanters across the US. Participants were board certificated, implanters of CIEDs, with varying experience (1–25 years), in various hospital settings. Of the respondents, 97% reported routine use of systemic antibiotics pre-operatively. About two-thirds of implanters continue systemic antibiotics post-operatively, with half continuing antibiotics for >24 h; 83% of implanters add antibiotic to saline for the purpose of irrigating the wound; 55% routinely use ENVELOPE on approximately 38% of patients. Common reasons cited for ENVELOPE use were infection concerns, significant risk factors, prior device infection, and immunosuppressed status. Two-thirds of respondents use systemic antibiotics during generator changes, with >50% continuing antibiotics for >24 h. This study suggests wide variations in practice among implanters. Additional attention to existing guidelines and evidence regarding appropriate use of ENVELOPE is still needed. [ABSTRACT FROM AUTHOR]

Introduction: The impact of transcatheter aortic valve replacement (TAVR) on sex disparities has not been well established. This study sought to examine the impact of sex on outcomes following aortic valve replacement (AVR) for aortic stenosis (AS) in the era of routine TAVR. Methods: We performed a cross-sectional analysis of the National Inpatient Sample (2009–18) to study AS visits for all AVR and in-hospital outcomes as a function of sex. Survey estimation commands were used to provide national estimates. Results: There were an estimated 431,344 surgical AVR (SAVR) and 189,137 TAVR inpatient visits. Mortality was higher in women after SAVR (3.8% ± 0.1 vs. 2.7% ± 0.07, p < 0.001) and TAVR (2.4% ± 0.1 vs. 1.7% ± 0.1, p < 0.001) compared to men. Female patients undergoing SAVR had higher rates of permanent pacemaker (PPM) implantation, stroke, and bleeding (5.9% ± 0.1 vs. 5% ± 0.1, 2.8% ± 0.1 vs. 2.3% ± 0.07, and 37.8% ± 0.8 vs. 29.8% ± 0.6; p < 0.001, respectively) but lower rates of acute kidney injury (AKI) (16.4% ± 0.3 vs. 20.3% ± 0.3, p < 0.001). Women undergoing TAVR had higher rates of stroke and bleeding (2.4% ± 0.1 vs. 1.6% ± 0.09 and 28.7% ± 0.6 vs. 22% ± 0.5; p < 0.001, respectively) but lower rates of PPM and AKI (9.5% ± 0.3 vs. 10.7% ± 0.2 and 11.3% ± 0.3 vs. 13.4% ± 0.3; p < 0.001, respectively). Compared with isolated SAVR, isolated TAVR was associated with lower mortality in women during 2016–18, both after multivariable adjustment (OR = 0.40; 95% CI, 0.27–0.60) and propensity matching (mean difference 0.66% ± 0.2); however, there was no difference in men. Conclusion: Although women continue to have higher in-hospital mortality following both TAVR and SAVR as compared to men, TAVR is associated with a lower in-hospital mortality in women compared to SAVR. Thus, TAVR may represent a potential intervention to narrow the sex-based disparities in the management of AS. [ABSTRACT FROM AUTHOR]

Matrix metalloproteinase-3 (MMP-3), or stromelysin-1, is a matrix metalloproteinase which is expressed in atherosclerotic plaques and which has been implicated in the pathogenesis of acute coronary syndrome (ACS). Functional polymorphisms in the promoter region of the human MMP-3 gene resulting in an increased expression of MMP-3 have been shown to predict the risk of incident myocardial infarction (MI). However, there have been no studies that have specifically examined the utility of baseline plasma MMP-3 levels for the prediction of long-term MI. In this study, baseline plasma MMP-3 levels were measured in 355 male patients who were referred for coronary angiography and followed prospectively for the development of enzymatically confirmed MI out to 5 years. After adjustment for a variety of baseline clinical, angiographic, and laboratory parameters, plasma MMP-3 levels were an independent predictor of MI at 5 years (hazards ratio 1.42, 95% CI 1.13 to 1.79; p = 0.0023). Furthermore, in 5 additional multivariate models that included a variety of contemporary biomarkers associated with adverse outcomes and MI, MMP-3 remained an independent predictor of MI at 5 years. Similar results were obtained when the analyses were restricted to the subpopulation of patients presenting with ACS. In conclusion, elevated levels of MMP-3 are associated with an increased risk of long-term MI in patients with and without ACS referred for coronary angiography. Furthermore, this association is independent of a variety of clinical, angiographic, laboratory variables, including biomarkers with established prognostic efficacy for the prediction of MI. [ABSTRACT FROM AUTHOR]

Introduction: The choice between a mechanical versus a bioprosthetic valve in aortic valve replacement (AVR) is based on life expectancy, bleeding risk and comorbidities, since bioprosthetic AVR (bAVR) are associated with a more rapid structural deterioration compared to mechanical AVR (mAVR). The impact of widespread transcatheter valve replacements, on the decision to use bAVR versus mAVR, in the contemporary era and subsequent outcomes remain to be determined. Methods: The National Inpatient database (2009–2018) was used to study trends in admissions for bAVR and mAVR and in‐hospital mortality and outcomes over time. Survey estimation commands were used to determine weighted national estimates. Results: There were 700,896 ± 18,285 inpatient visits for AVR with 70.1% (95% CI 69.2%–71.1%) and 29.9% (95% CI 28.9%–30.8%) visits for bAVR and mAVR, respectively. Those undergoing bAVR were significantly older (bAVR [69.8 years] vs. mAVR [62.7 years] p <.001]. The rates of mAVR decreased across all age groups during the study period (ptrend <.001), including patients ≤50 years (ptrend <.001). In‐hospital mortality for mAVR recipients was higher, both after multivariable adjustment (OR 1.35 95% CI 1.26–1.45 p <.001) and propensity matching (mean difference 0.846% ± 0.19%). Conclusion: In the contemporary era, the utilization of mAVR has decreased across all age groups, including those younger than 50 years old. Although mAVR recipients were healthier with less comorbidities, inpatient mortality was higher after mAVR compared to bAVR. In addition to understanding causes for higher in‐hospital mortality after mAVR, future research should focus on developing transcatheter valve replacement friendly bAVR. [ABSTRACT FROM AUTHOR]

Introduction: Stress-induced cardiomyopathy (SIC) has a higher incidence in Caucasians (CAUCs) compared to African-Americans (AAs). Whether this is due to racial predisposition, selection bias, or environmental factors remains unclear. Hypothesis: We hypothesize that people from lower socioeconomic strata (SES) have a lower incidence of SIC. It is possible that the incidence of SIC could be similar among CAUCs and AAs at the same SES. Stress preconditioning maybe protective in preventing SIC. Methods: Data of patients with the discharge diagnosis of SIC were extracted from the Myocardial Infarction Data Acquisition System spanning the period from 2006 through 2015. The incidence of SIC among CAUCs and AAs was compared per 100,000 New Jersey population and examined across income brackets. CAUCs and AAs data were compared using two-sample proportion tests. Results: During the study period, CAUCs had an overall higher incidence of SIC compared to AAs, 0.017% versus 0.0084% per 100,000 population (p value <0.0001). This difference persisted after a logistic regression adjustment (p = 0.0064). CAUCs in the income brackets of 30–40k had lower incidence of SIC than those in the 60–80k income bracket (p = 0.0156). Those with an income of 60–80k had lower incidence of SIC compared to those with an income of 80–100k. AAs with income between 30 and 60k had a lower incidence of SIC than CAUCs (p = 0.0330). Conclusions: CAUCs exhibited a trend towards less SIC as a function of lower income. This was not observed among AAs. AAs had a lower incidence of SIC. Our study suggests that SES has a protective effect among CAUCs. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine whether defibrillation waveform duration adjustment with single-coil defibrillation leads can be used to increase the proportion of patients with satisfactory defibrillation thresholds (DFTs). A retrospective analysis of the DFT levels for 105 patients with implantable cardioverter-defibrillator devices and a single-coil defibrillation lead was performed. Two groups of patients were compared: 34 patients who had undergone waveform tuning (group A) and 71 patients with a fixed-tilt waveform (group B). Additional data including demographics, etiology, New York Heart Association functional class, left ventricular ejection fraction, high-voltage lead impedance and medications were gathered to determine what effect these variables had on the DFT levels. Of the 34 patients who had undergone waveform adjustment (group A), 27 (79%) were found to have satisfactory DFTs, while 41 (58%) of the 71 patients with fixed-tilt devices (group B) had satisfactory DFTs. Waveform duration adjustment was found to significantly increase the proportion of patients with satisfactory DFTs (p = 0.03). Copyright © 2013 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Atrial fibrillation (AF) is the most common sustained atrial arrhythmia conferring a higher morbidity and mortality. Despite the increasing incidence of AF; available therapies are far from perfect. Dietary fish oils, containing omega 3 fatty acids, also called polyunsaturated fatty acid [PUFA] have demonstrated beneficial electrophysiological, autonomic and anti-inflammatory effects on both atrial and ventricular tissue. Multiple clinical trials, focusing on various subsets of patients with AF, have studied the role of PUFA and their potential role in reducing the incidence of this common arrhythmia. While PUFA appears to have a beneficial effect in the primary prevention of AF in the elderly with structural heart disease, this benefit has not been universally observed. In the secondary prevention of AF, PUFA seems to have a greater impact in the reducing AF in patients with paroxysmal or persistent AF, stages of AF associated with less atrial fibrosis and negative structural remodeling. However, AF suppression has not been consistently demonstrated in clinical trials. In patients undergoing heart surgery, increasing PUFA intake has yielded mixed results in terms of AF prevention post-operatively; however, increased PUFA has been associated with a reduction in hospital stay. Therefore recommending the use of PUFA for the purpose of AF reduction remains controversial. This is in part attributable to the complexity of AF. Other conflicting variables include: heterogeneous patient populations studied; variable dosing; duration of follow-up; comorbidities; and, concomitant pharmacotherapy. This review article reviews in detail available basic and clinical research studies of fish oil in the treatment of AF, and its role in the treatment of this common disorder. [ABSTRACT FROM AUTHOR]

The article presents a case study of a woman subjected to a preoperative evaluation before undergoing noncardiac surgery for her uterine fibroid tumor. The resting electrocardiogram (ECG) of the patient manifested sinus arrhythmia with complete heart block (CHB) with a junctional escape rhythm. The researchers note that the case shows the significance of exercise ECG stress testing to patients in CHB to assess their need for an electronic pacemaker or other therapy.

Patients infected with novel coronavirus (SARS‐CoV‐2) can present with a variety of arrhythmias. We report an unusual case of reversible complete heart block (CHB) in the setting of acute coronavirus disease 2019 (COVID‐19). A 23‐year‐old male with a history of Hodgkin's Lymphoma presented with dizziness and syncope. He was found to be in CHB associated with hypotension requiring a transvenous pacemaker. Methylprednisolone and remdesivir were started with rapid resolution of the CHB. Further study is needed to determine the mechanism of CHB in COVID‐19. This case underscores the importance of including COVID‐19 in one's differential diagnosis for acute CHB. [ABSTRACT FROM AUTHOR]

Change in Atrial Activation During AV Node Modification. Introduction: Despite the great success in treating AV nodal reentrant tachycardia (AVNRT) with radiofrequency modification of the AV node, the dimensions of the electrophysiologic circuit of this arrhythmia remain unclear, and simple models fail to explain all tachycardia-related phenomena. Methods and Results: We describe three unusual cases of supraventricular tachycardia (SVT). In all three cases, retrograde atrial activation during ventricular pacing or during SVT manifested local left atrial electrograms recorded from the coronary sinus preceding the septal atrial electrograms (eccentric activation), with earliest atrial activity at the lateral or posterolateral mitral annulus. Electrophysiologic maneuvers and observations were consistent with AVNRT as the mechanism in each case. In all cases, radiofrequency modification of the AV node eliminated inducible SVT and abolished dual pathway AV nodal physiology. The retrograde atrial activation sequence during ventricular pacing changed after ablation in each case, with septal atrial electrograms preceding left atrial electrograms recorded from the coronary sinus (concentric activation). Conclusion: The observations in these cases cannot be explained by the traditional model of slow, fast, and intermediate AV nodal pathways. A model incorporating a circuit close to the AV node with left atrial and coronary sinus connections is proposed.(J Cardiovasc Electrophysiol, Vol. 14, pp. 461-466, May 2003). [ABSTRACT FROM AUTHOR]

Introduction: The most feared complication of pulmonary vein isolation (PVI) is an atrioesophageal fistula (AEF). While rare (0.1‐0.25%), primary surgical closure (as opposed to esophageal stenting) is associated with lower mortality. Pericardioesophageal fistula (PEF) may present prior to fistulization into the atrium. Unfortunately, data on the optimal management of PEFs are lacking. Case report: Seventy‐one‐year‐old male with AF presented with chest pain 3 weeks after radiofrequency PVI. Computed tomography angiography (CTA) chest and echocardiogram showed pneumopericardium. Barium esophagram showed extravasation from esophagus into the pericardium without connection to the left atrium. Sternotomy with mediastinal exploration exposed the pericardial defect, over which a CorMatrix patch was placed. The fistula was then stented endoscopically with endosuture fixation. Poststent esophagram did not show barium leak, and the patient was discharged home. One week later, the patient returned with enterococcal and candida bacteremia and an acute right parietal/occipital lobe infarct. Barium esophagram showed contrast extravasation into the pericardium. The patient rapidly succumbed to his illness and died. Autopsy revealed pericardial abscess posterior to the LA in communication with the esophagus. Extension to the LA was not seen. Conclusion: While the surgical treatment of AEF is relatively well established, there is no consensus in the management of PEF. While prior small series have suggested PEF may be managed with esophageal stenting, our case illustrates the limitations of this approach. [ABSTRACT FROM AUTHOR]

Standard electrocardiographic criteria for exercise testing require near maximal exertion and fail to detect ischemia in the presence of previous infarction or conduction or repolarization abnormalities, in women, or in the presence of certain drugs. Changes in P-wave morphology have been suggested as having diagnostic utility; however, no specific criteria exist, and it is not clear which changes are most useful. This investigation evaluated the ability to detect the presence of coronary artery disease by examining changes in P-wave morphology during exercise. A group of 123 consecutive patients underwent maximum (symptom-limited) exercise nuclear stress tests. The electrocardiograms at rest, 2 minutes of exercise, 50% of maximum exercise time, maximum exercise, and 3 minutes of recovery were analyzed for the duration of the P wave in lead II, the duration of the terminal negative component of the P wave in lead V1, the amplitude of the terminal negative component of the P wave in lead V1, and the duration of the P wave in lead V5. These variables were then analyzed for their relation to the presence of perfusion defects. Of all the P-wave criteria tested, a change in amplitude of the negative component of the P wave in lead V1 from at rest to 50% of maximum exercise time of &#60;0.025 mV was the most predictive of coronary artery disease. [Copyright &y& Elsevier]

Background: Mitral regurgitation (MR) is commonly encountered in patients with severe aortic stenosis (AS). However, its independent impact on mortality in patients undergoing transcatheter aortic valve implantation (TAVI) has not been established. Methods: We performed a systematic search for studies reporting characteristics and outcome of patients with and without significant MR and/or adjusted mortality associated with MR post-TAVI. We conducted a meta-analysis of quantitative data. Results: Seventeen studies with 20,717 patients compared outcomes and group characteristics. Twenty-one studies with 32,257 patients reported adjusted odds of mortality associated with MR. Patients with MR were older, had a higher Society of Thoracic Surgeons score, lower left ventricular ejection fraction, a higher incidence of prior myocardial infarction, atrial fibrillation, and a trend towards higher NYHA class III/IV, but had similar mean gradient, gender, and chronic kidney disease. The MR patients had a higher unadjusted short-term (RR = 1.46, 95% CI 1.30–1.65) and long-term mortality (RR = 1.40, 95% CI 1.18–1.65). However, 16 of 21 studies with 27,777 patients found no association between MR and mortality after adjusting for baseline variables. In greater than half of the patients (0.56, 95% CI 0.45–0.66) MR improved by at least one grade following TAVI. Conclusion: The patients with MR undergoing TAVI have a higher burden of risk factors which can independently impact mortality. There is a lack of robust evidence supporting an increased mortality in MR patients, after adjusting for other compounding variables. MR tends to improve in the majority of patients post-TAVI. [ABSTRACT FROM AUTHOR]

Purpose: Pulmonary vein isolation (PVI) for atrial fibrillation has been shown to result in inexcitability of a large fraction of pulmonary veins (PVs), but the mechanism is unknown. We investigated the mechanism of PV inexcitability by assessing the effects of PVI on the electrophysiology of PV sleeves. Methods: Patients undergoing first‐time radiofrequency PVI were studied. Capture threshold, effective refractory period (ERP), and excitability were measured in PVs and the left atrial appendage (LAA) before and after ablation. Adenosine was used to assess both transient reconnection and transient venous re‐excitability. Results: We assessed 248 veins among 67 patients. Mean PV ERP (249.7 ± 54.0 ms) and capture threshold (1.4 ± 1.6 mA) increased to 300.5 ± 67.1 and 5.7 ± 5.6 mA, respectively (P <.0001 for both) in the 26.9% PVs that remained excitable, but no change was noted in either measure in the LAA. In 16.3% of the 73.1% inexcitable veins, transient PV re‐excitability (as opposed to reconnection) was seen with adenosine administration. Conclusions: Antral PVI causes inexcitability in a majority of the PVs, which can transiently be restored in some with adenosine. Among PVs that remain excitable, ERP and capture threshold increase significantly. These data imply resting membrane potential depolarization of the of PV myocardial sleeves. As PV inexcitability hampers the assessment of entrance and exit block, demonstrating transient PV re‐excitability during adenosine administration helps ensure true isolation. [ABSTRACT FROM AUTHOR]

Objective: Caffeine has been considered a trigger for atrial fibrillation (AF). We conducted a meta-analysis including a dose-response analysis to assess the relationship between caffeine consumed and incidence of AF. Methods: Data from selected studies represented 176,675 subjects (AF in 9,987 [5.7%]). Caffeine content varied widely, ranging from 40 to 180 mg per cup of coffee. For purposes of the calculations in this study, we assumed 140 mg of caffeine in a standard 12-oz cup of coffee. Results: No significant difference was found in AF incidence when the subjects consuming less than 2 cups of coffee per day were compared to subjects with higher consumption, 1.068 (0.937–1.216). The risk of AF was higher among subjects consuming less than 2 cups of coffee daily when compared to higher daily consumption subjects. A lower incidence of AF was found among people consuming more than 436 mg daily. Conclusion: The incidence of AF is not increased by coffee consumption. In fact, we found a lower incidence of AF when caffeine consumption exceeded 436 mg/day. Therefore, based on available evidence there is no association between caffeine intake and AF risk. [ABSTRACT FROM AUTHOR]

Ca entry through atrial L-type Calcium channels (α 1C and α 1D ) play an important role in muscular contraction, regulation of gene expression, and release of hormones including atrial natriuretic peptide (ANP), and brain natriuretic peptide (BNP). α 1D Ca channel is exclusively expressed in atria, and has been shown to play a key role in the pathogenesis of atrial fibrillation. Recent data have shown that the small conductance calcium-activated potassium channel, SK4 is also atrial specific and also contributes prominently to the secretion of ANP and BNP. However, its functional role in the heart is still poorly understood. Here we used α 1D gene heterozygous (α 1D +/- ) mice and HL-1 cells to determine the functional contribution of SK4 channels to α 1D –dependent regulation of ANP and BNP secretion in response to endothelin (ET), and/or mechanical stretch. Immunoprecipitation with α 1D specific antibody and western blotting with SK4 specific antibody on the immuno-precipitated protein complex showed a band at 50 KDa confirming the presence of SK4 in the complex and provided evidence of interaction between SK4 and α 1D channels. Using RT-PCR, we observed a 2.9 fold decrease in expression of Cacna1d (gene encoding α 1D ) mRNA in atria from α 1D +/− mice. The decrease in α 1D mRNA corresponded with a 4.2 fold decrease in Kcnn4 (gene encoding SK4) mRNA from α 1D +/− mice. These changes were paralleled with a 77% decrease in BNP serum levels from α 1D +/− mice. When α 1D was knocked down in HL-1cardiomyocytes using CRISPR/Cas9 technology, a 97% decrease in secreted BNP was observed even in cells subjected to stretch and endothelin. In conclusion, our data are first to show that α 1D Ca and SK4 channels are coupled in the atria, and that deletion of α 1D leads to decreased SK4 mRNA and BNP secretion providing evidence for a novel role of α 1D in atrial endocrine function. Elucidating the regulatory factors that underlie the secretory function of atria will identify novel therapeutic targets for treatment and prevention of cardiac arrhythmias such as atrial fibrillation. [ABSTRACT FROM AUTHOR]

Background: Head-up tilt table testing (HUTT) is time-consuming and associated with increased patient morbidity. Hemodynamic changes that occur during the early phase of HUTT may be predictive of neurocardiogenic syncope. Methods: A retrospective chart review was performed in 119 consecutive African Americans (57 ± 19) who underwent HUTT for evaluation of syncope of unknown etiology. Positive responses were defined as the development of symptoms linked with a systolic blood pressure (BP) <90 mm Hg, heart rate <50 b.p.m. or sinus arrest >3 s. Hemodynamic variables during the passive phase of HUTT were analyzed and results were then classified as a function of various predictors. Results: Sixty-two subjects (52%) had positive HUTT, and 57 (48%) had negative HUTT. Early changes in BP variables from baseline significantly predicted HUTT responses (p < 0.05). There was also a significant interaction between age and BP. An algorithm based on age and BP was developed which had positive and negative predictive values of 67.7 and 93%, respectively, with an accuracy of 79.8%. Conclusion: A novel algorithm utilizing the patients' age and changes in both systolic and diastolic BP during the early phase of HUTT enables the prediction of HUTT results without the use of vasoactive stimulation, allowing for rapid diagnosis, decreased patient morbidity and reduction in costs. [ABSTRACT FROM AUTHOR]

Sinus bradycardia and associated isorhythmic AV dissociation may be seen during dobutamine stress echocardiography. This phenomenon is usually considered a benign peri-procedural event and is thought to be secondary to the Bezold-Jarisch reflex, with profound heart rate decrease secondary to a marked increased in vagal efferent discharge. To the best of our knowledge, dobutamine stress echocardiography unmasking clinically relevant sinus node dysfunction has never been reported. We report a case of a 50-year-old man presenting with chest pain and a history of syncope, who had worsening sinus bradycardia with isorhythmic AV dissociation during dobutamine stress echocardiography. An invasive electrophysiological study revealed marked sinus node dysfunction. The patient was referred for the insertion of a permanent pacemaker for sinus node dysfunction, chronotropic incompetence and symptomatic bradycardia. Dobutamine-associated bradycardia may not always be a benign peri-procedural physiologic effect, as in this case it may unmask clinically significant sinus node dysfunction. Copyright © 2011 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]