Predictive Value of ST-Segment Elevation in Lead aVR for Left Main and/or Three-Vessel Disease in Non-ST-Segment Elevation Myocardial Infarction.

BACKGROUND: ST-segment elevation in lead aVR predicts left main and/or three-vessel disease (LM/3VD) in patients with acute coronary syndromes. ST-segment elevation in lead aVR is generally reciprocal to and accompanied by ST-segment depression in precordial leads. Previous studies have assessed the independent predictive value of ST-segment elevation in lead aVR for LM/3VD in non-ST-segment elevation acute coronary syndrome and have reported conflicting results. METHODS: We performed a retrospective analysis of 379 patients with non-ST-segment elevation myocardial infarction (NSTEMI). Electrocardiograms on presentation were reviewed especially for ST-segment elevation ≥0.05 mV in lead aVR and ST-segment depression ≥0.05 mV in more than two contiguous leads in any other leads. RESULTS: Among 379 patients, 97 (26%) patients had ST-segment elevation in lead aVR and 88 (23%) patients had LM/3VD. Patients with ST-segment elevation in lead aVR had a higher rate of LM/3VD (39% vs. 18%; P < 0.001) and in-hospital revascularization (73% vs. 60%; P = 0.02) driven by a higher rate of in-hospital coronary artery bypass grafting (19% vs. 7%; P < 0.001) than those without ST-segment elevation in lead aVR. On multivariate analysis, ST-segment elevation in lead aVR (odds ratio [OR] 2.05; 95% confidence interval [CI] 1.10-3.77; P = 0.02) and ST-segment depression in leads V1 -V4 (OR 2.99; 95% CI 1.46-6.15; P = 0.003) were independent predictors of LM/3VD. CONCLUSION: This study demonstrates that ST-segment elevation in lead aVR is an independent predictor of LM/3VD in patients with NSTEMI.

Tpeak - Tend and Tpeak - Tend /QT ratio as markers of ventricular arrhythmia risk in cardiac resynchronization therapy patients.

BACKGROUND: Cardiac resynchronization therapy (CRT) increases transmural dispersion of repolarization (TDR) and can be pro-arrhythmic. However, overall arrhythmia risk was not increased in large-scale CRT clinical trials. Increased TDR as measured by T(peak ) -T(end) (TpTe) was associated with arrhythmia risk in CRT in a single-center study. This study investigates whether QT interval, TpTe, and TpTe/QT ratio are associated with ventricular arrhythmias in patients with CRT-defibrillator (CRT-D). METHODS: Post-CRT-D implant electrocardiograms of 128 patients (age 71.3 years ± 10.3) with at least 2 months of follow-up at our institution's device clinic (mean follow-up of 28.5 months ± 17) were analyzed for QT interval, TpTe, and TpTe/QT ratio. Incidence of ventricular arrhythmias was determined based on routine and directed device interrogations. RESULTS: Appropriate implantable cardioverter-defibrillator therapy for sustained ventricular tachycardia or ventricular fibrillation was delivered in 18 patients (14%), and nonsustained ventricular tachycardia (NSVT) was detected but did not require therapy in 58 patients (45%). Patients who received appropriate defibrillator therapy had increased TpTe/QT ratio (0.24 ± 0.03 ms vs 0.20 ± 0.04, P = 0.0002) and increased TpTe (105.56 ± 20.36 vs 87.82 ± 22.32 ms, P = 0.002), and patients with NSVT had increased TpTe/QT ratio (0.22 ± 0.04 vs 0.20 ± 0.04, P = 0.016). Increased QT interval was not associated with risk of ventricular arrhythmia. The relative risk for appropriate defibrillator therapy of T(p) T(e) /QT ratio ≥ 0.25 was 3.24 (P = 0.016). CONCLUSION: Increased TpTe and increased TpTe/QT ratio are associated with increased incidence of ventricular arrhythmias in CRT-D. The utility of TpTe interval and TpTe/QT ratio as potentially modifiable risk factors for ventricular arrhythmias in CRT requires further study.

Impact of Age on Subcutaneous Implantable Cardioverter-Defibrillator in a Large Patient Cohort: Mid-Term Follow-Up.

BACKGROUND: The subcutaneous implantable cardioverter-defibrillator (S-ICD) is an accepted alternative to transvenous (TV) ICD to provide defibrillation therapy to treat life-threatening ventricular tachyarrhythmias in high-risk patients. S-ICD outcomes by age group have not been reported. OBJECTIVES: In this study, the authors sought to report S-ICD outcomes in different age groups in a multicenter S-ICD post-approval study (PAS) involving the largest cohort of patients ever reported. METHODS: Patients were prospectively enrolled in the S-ICD PAS and stratified based on age: young, aged 15-34 years; adult, aged 35-69 years; and elderly, aged ≥70 years. Patient characteristics and clinical outcomes through 3 years of follow up after implantation were compared. RESULTS: The S-ICD PAS enrolled 1,637 patients. Elderly patients were more likely to receive an S-ICD as a replacement of a TV-ICD (15.1% elderly vs 12.3% adult vs 7.4% young). Secondary prevention indication decreased with age (32.7% young vs 22.2% adult vs 20.5% elderly). Mortality rate was significantly higher in the elderly group (24.0% elderly vs 13.0% adult vs 7.4% young; P < 0.0001), whereas the complication rate did not differ significantly (12.3% young vs 11.3% adult vs 8.1% elderly). Rates of appropriate shock (12.7% young vs 13.0% adult vs 13.8% elderly) and inappropriate shock (7.8% young vs 9.1% adult vs 8.8% elderly) rates did not differ between groups (P = 0.96 and P = 0.98, respectively). CONCLUSIONS: Implant complications and appropriate and inappropriate shock rates were similar among age groups. S-ICD for secondary prevention was more common in the young group. Replacing a TV-ICD for an S-ICD increases with age. (S-ICD System Post-Approval Study; NCT01736618).

Warfarin in haemodialysis patients with atrial fibrillation: what benefit?

Warfarin is commonly used to prevent stroke in patients with atrial fibrillation; however, patients on haemodialysis may not derive the same benefit from warfarin as the general population. There are no randomized controlled studies in dialysis patients which demonstrate the efficacy of warfarin in preventing stroke. In fact, warfarin places the dialysis patient at increased risk for haemorrhagic stroke and possibly ischaemic stroke. Additionally, warfarin increases the risk of major bleeding and has been associated with vascular calcification. Routine use of warfarin in dialysis for stroke prevention should be discouraged, and therapy should only be reserved for dialysis patients at high risk for thrombo-embolic stroke and carefully monitored if implemented.

1-Year Prospective Evaluation of Clinical Outcomes and Shocks: The Subcutaneous ICD Post Approval Study.

OBJECTIVES: This study evaluated spontaneous arrhythmias and clinical outcomes in the S-ICD System PAS (Subcutaneous Implantable Cardioverter-Defibrillator Post Approval Study) cohort. BACKGROUND: The U.S. S-ICD PAS trial patient population more closely resembles transvenous ICD cohorts than earlier studies, which included many patients with little structural heart disease and few comorbidities. Early outcomes and low peri-operative complication rates were demonstrated in the S-ICD PAS cohort, but there are no data detailing spontaneous arrhythmias and clinical outcomes. METHODS: The S-ICD PAS prospective registry included 1,637 de novo patients from 86 U.S. centers. Descriptive statistics, Kaplan-Meier time to event, and multivariate logistic regression were performed using data out to 365 days. RESULTS: Patients (68.5% men; mean ejection fraction of 32.0%; 42.9% ischemic; 13.4% on dialysis) underwent implantation for primary (76.6%) or secondary prevention indication. The complication-free rate was 92.5%. The appropriate shock (AS) rate was 5.3%. A total of 395 ventricular tachycardia (VT) or fibrillation (VF) episodes were appropriately sensed, with 131 (33.2%) self-terminating. First and final shock efficacy (up to 5 shocks) for the 127 discrete AS episodes were 91.3% and 100.0%, respectively. Discrete AS episodes included 67 monomorphic VT (MVT) and 60 polymorphic VT (PVT)/VF, with first shock efficacy of 95.2% and 86.7%, respectively. There were 19 storm events in 18 subjects, with 84.2% conversion success. Storm episodes were more likely PVT/VF (98 of 137). CONCLUSIONS: In the first year after implantation, a predominantly primary prevention population with low ejection fraction demonstrated a high complication-free rate and spontaneous event shock efficacy for MVT and PVT/VF arrhythmias at rapid ventricular rates. (Subcutaneous Implantable Cardioverter-Defibrillator System Post Approval Study [S-ICD PAS; NCT01736618).

Follow-up imaging after left atrial appendage closure.

BACKGROUND: Because device-related thrombus (DRT) portends a poor prognosis after left atrial appendage closure with the Watchman device, surveillance transesophageal echocardiography (TEE) is recommended at 45 days and 1 year. However, oral anticoagulants are just discontinued at 45 days, rendering this early TEE unlikely to detect DRT. Indeed, DRT is most likely to occur after instituting aspirin monotherapy. OBJECTIVE: The purpose of this study was to evaluate the alternative strategy of first TEE imaging (or computed tomography) at 4 months post-Watchman implantation. METHODS: After Food and Drug Administration approval, consecutive patients undergoing Watchman implantation at 2 centers received TEE or CT at 4 months and 1 year, along with a truncated drug regimen: 6 weeks of an oral anticoagulant (or clopidogrel in a subset) plus aspirin, then 6 weeks of dual antiplatelet therapy, and finally aspirin monotherapy. RESULTS: Of the 530-patient cohort (mean age 78.7±7.9 years; 65.5% (n = 347) male; CHA2DS2-VASc score 4.5±1.4), 465 patients (87.7%) received 4-month imaging: 83.0% (440 of 530) TEE and 4.7% (25 of 530) computed tomography. Over a median follow-up of 12 months, 16 ischemic strokes (ISs), 8 transient ischemic attacks, and 1 systemic embolization occurred. Importantly, no IS occurred between 45 days and 4 months; the sole transient ischemic attack in this period (at ∼2 months) occurred 1 week after transcatheter aortic valve replacement. DRT was detected in 2.4% (11 of 465) at 4 months and 0.9% (2 of 214) at 1 year. No IS, but 1 leg embolization, was observed after DRT detection. CONCLUSION: Delaying the first imaging post-Watchman implantation to 4 months was associated with no IS between 45 days and 4 months, the "vulnerable" period of this follow-up strategy.

Termination of recurrent ventricular tachycardia by continuous positive airway pressure ventilation.

We report a case of hypertrophic cardiomyopathy with recurrent ventricular tachycardia that resolved after initiating continuous positive airway pressure therapy.

Atrial rate and rhythm abnormalities in a patient with hyperkalemia.

A 67 year old man presented with a serum potassium of 7.7 mEq/L and slow atrial flutter with variable A-V block and peaked T waves. Initial treatment for hyperkalemia was followed by an increase in the atrial flutter rate to 300 beats per minute. After hemodialysis the rhythm converted to sinus.

Successful transition to buprenorphine in a patient with methadone-induced torsades de pointes.

A 56-year-old-man presented with syncope and torsades de pointes secondary to methadone-induced QT prolongation. After transition from methadone to buprenorphine, a partial mu-opiate-receptor agonist and a kappa-opiate-receptor antagonist, the QT normalized and ventricular arrhythmias resolved. Buprenorphine should be used for opiate dependence and chronic pain in patients with methadone-induced QT prolongation and as first line therapy in patients with risk factors for torsades de pointes.

Non-ischemic cardiomyopathy patients derive superior mortality benefit from cardiac resynchronization therapy.

BACKGROUND: Cardiac Resynchronization Therapy (CRT) is indicated for the treatment of advanced heart failure with severe systolic dysfunction and intraventricular conduction delay. Patient selection for this technology is vital, though it remains unclear which patients benefit most from CRT. We tested the hypothesis that patients with non-ischemic cardiomyopathy have a superior mortality benefit from CRT than ischemic cardiomyopathy patients. METHODS: We evaluated 95 CRT patients to determine which factors predict mortality. RESULTS: Patients with non-ischemic cardiomyopathy had a significantly better prognosis than patients with ischemic cardiomyopathy. CONCLUSION: Larger prospective studies can substantiate this finding and better delineate which patients benefit most from CRT.

Pneumomediastinum and right sided pneumothorax following dual chamber-ICD implantation.

A 64-year-old-male with ischemic cardiomyopathy and a severely reduced left ventricular ejection fraction underwent a left sided ICD implantation for primary prophylaxis. Given a history of sarcoidosis and bifasicular block on ECG, a dual chamber device was placed in anticipation of progressive conduction disease. The patient returned 2 days after implantation with a right sided tension pneumothorax. A chest tube was immediately placed with hemodynamic and clinical improvement. CT chest revealed extrusion of the atrial lead through the right atrial appendage. The atrial lead was removed without incident.

Relation of T-wave inversion in Q-wave acute myocardial infarction to myocardial viability on resting rubidium-82 and 18-fluoro-deoxyglucose positron emission tomography imaging.

T-wave inversion in areas of Q-wave myocardial infarction has been advocated as a predictor of myocardial viability. However, the predictive value of this electrocardiographic finding in distinguishing viable from nonviable muscle is not fully defined. Thus, we correlated electrocardiographic Q waves and a measure of T-wave inversion with the results of rubidium-82 (Rb-82) and 18-fluoro-deoxyglucose-positron emission tomography (FDG-PET) imaging at rest. We analyzed 35 Q-wave myocardial infarct regions in 25 patients. Nineteen of the 35 (54%) were judged viable by Rb-82/FDG-PET. Using the Novacode T-wave score, T-wave inversion was present in 11 of 19 regions (58%) with viability and 5 of 16 regions (31%) without viability. Thus, neither Q waves nor T-wave inversion can accurately predict myocardial viability in patients with Q-wave myocardial infarction.

A rare, late complication after automated implantable cardioverter-defibrillator placement.

This article describes an interesting case of automated implantable cardioverter defibrillator (AICD) extrusion fifteen months after implantation. The case report is followed by a discussion of the causes and treatment of skin erosion following pacemaker/AICD insertion.

An unusual tachycardia.

The following article presents an unusual case of atrial tachycardia, initially misdiagnosed due to a lack of clear P waves. The diagnosis was eventually confirmed using the atrial electrogram from the patient's pacemaker.

The Use of Ranolazine in the Management of Recurrent Atrial Fibrillation After Percutaneous Radiofrequency Ablation.

Long-term medical treatment options for atrial fibrillation (AF) include rate-control as well as rhythm-control therapy with various antiarrhythmics. However, because of the limited efficacy and potential side effects of these medications, percutaneous and surgical ablations in AF patients have evolved as alternative or additional approaches to achieve rhythm-control. Nonetheless, arrhythmia recurrences may also occur after these procedures. Thus, the search for complementary treatment options continues.Ranolazine possesses antiarrhythmic effects in atrial myocytes via blockade of sodium channels. These properties facilitate AF suppression in animal models and human subjects. We report a patient with persistent AF that was refractory to medical management and percutaneous catheter ablation. She has remained in sinus rhythm for at least 18 months after the initiation of ranolazine.

Effectiveness of Telemetry Guidelines in Predicting Clinically Significant Arrhythmias in Hospitalized Patients.

BACKGROUND: Cardiac rhythm monitoring is widely applied on hospitalized patients. However, its value has not been evaluated systematically. METHODS: This study considered the utility of our institutional telemetry guidelines in predicting clinically significant arrhythmias. A retrospective analysis was performed of 562 patients admitted to the telemetry unit. A total of 1932 monitoring days were evaluated. Patients were divided into 2 groups based on telemetry guidelines: "telemetry indicated" and "telemetry not indicated". RESULTS: Differences in arrhythmia event rates and pre-defined clinical significance were determined. One hundred and forty-four (34%) vs. 16 (11%) patients had at least one arrhythmic event in the "telemetry indicated" group compared with the "telemetry not indicated" group, respectively (P = 0.001). No patient in the "telemetry not indicated" group had a clinically significant arrhythmia. In contrast, of patients in the "telemetry indicated" group who had at least one arrhythmic event, 36% were considered clinically significant (P < 0.05). CONCLUSION: In conclusion, this study validates and supports the use of our institutional telemetry guidelines to allocate this resource appropriately and predict clinically significant arrhythmias.