Implantable cardioverter defibrillators in patients with orthotopic heart transplant: A multicenter case series.

BACKGROUND: Sudden cardiac death (SCD) is common after orthotopic heart transplant (OHT). No clear guidelines for implantable cardioverter defibrillator (ICD) implantation in OHT patients at high risk for SCD currently exist. OBJECTIVES: To assess the safety, efficacy, and benefit of ICDs and resynchronization therapy post-OHT. We also provide a systematic review of previous reports. METHODS: A retrospective multicenter cohort study within the United States. Patients with ICD post-OHT between 2000 and 2020 were identified. RESULTS: We analyzed 16 patients from 4 centers. The mean standard-deviation (SD) age was 43 (18) years at OHT and 51 (20) years at ICD implantation. The mean (SD) duration from OHT to ICD implantation was 9 (5) years. The mean (SD) left ventricular ejection fraction (LVEF) was 35% (17%). There were 2 (13%) postprocedural complications: 1 hematoma and 1 death. Mean (SD) follow-up was 24 (23) months. Survival rate was 63% (10/16) at 1 year and 56% (9/16) at 2 years, with 6/7 of those who died having LVEF < 35% at the time of the ICD implantation. Patients were more likely to receive appropriate therapy if their ICD was implanted for secondary (5/8) rather than primary (0/8) prevention (p = .007). Of those who did, 4 patients survived to 30 days post-ICD therapy. Severe CAV was not associated with the rate of appropriate therapy. CONCLUSIONS: Beneficial outcomes were observed when ICDs were implanted for secondary prevention only, and in patients with higher baseline LVEF. We also observed benefits with resynchronization therapy.

Termination of macroreentrant atrial arrhythmias by pacing stimuli without global propagation.

BACKGROUND: Electrical stimulation during ventricular tachycardia resulting in tachycardia termination without global propagation (TWGP) is a well-recognized phenomenon. However, there is a paucity of literature showing a similar phenomenon in atrial arrhythmias. OBJECTIVE: The purpose of the study was to evaluate the significance of TWGP in atrial arrhythmias. METHODS: Electrophysiological studies performed from 2000 to 2019 at Methodist Hospital, Indiana University were reviewed retrospectively. Thirty-four patients were identified in whom stimulation during atrial tachycardia/flutter resulted in TWGP. RESULTS: Of the 34 patients, 12 (29%) had cavotricuspid isthmus (CTI)-dependent atrial flutter and 22 (71%) had other atrial arrhythmias during which TWGP was seen. Mean age of the population was 53 ± 13 years; and 68% were male. Previous catheter ablation for atrial fibrillation, atrial flutter, or other atrial tachyarrhythmias had been performed in 70.5%, and 44% previously had undergone cardiac surgery involving the atria. Congenital heart disease was present in 20.5%; 3 patients were status post lung transplant. Mean cycle length of atrial arrhythmia in which TWGP was seen was 317 ± 76 ms. The sites at which TWGP was seen reproducibly were highly specific for successful termination of the arrhythmias with radiofrequency energy. The arrhythmia circuits were 12 CTI-dependent atrial flutter, 11 left atrial macroreentrant atrial tachycardia (MRAT), 1 involving both left and right atria, and 8 were other right atrial MRAT. CONCLUSION: Termination of macroreentrant atrial arrhythmias by pacing stimuli without global propagation identifies a narrow diastolic isthmus at which catheter ablation is highly effective.

Removing the complexity from wide complex tachycardia.

Correctly diagnosing the cause of wide QRS tachycardias remain an area of difficulty for many clinicians. The authors provide a concise update to the different ECG algorithms that have been developed as well as caveats in their application.

Cryoballoon vs radiofrequency ablation of atrial fibrillation: insights from the Veterans Healthcare System.

PURPOSE: Catheter ablation is considered the mainstay treatment for drug-refractory atrial fibrillation (AF). The aims of our study were to compare the efficacy and safety of the most two currently approved approaches (point-by-point radiofrequency ablation (RFA), either with contact force (CF) or without contact force (nCF) catheters, and cryoballoon ablation (CBA)) in the Veterans Healthcare System. METHODS: We performed a retrospective study of patients who underwent ablation for treatment of AF at the veterans affairs healthcare system between 2013 and 2018. Only the first reported ablation procedure was included. RESULTS: We included 956 patients in the study (97.4% males, 91.5% Caucasians, 67% paroxysmal AF), with 682 patients in RFA-nCF, 139 in RFA-CF, and 135 in CBA. Thirty-day complication rates were comparable between the three groups with the exception of higher incidence of phrenic nerve injury in CBA group when compared to RFA-nCF (2.2% vs 0.0%, p < 0.01). Long-term recurrence rate of AF was significantly lower in the CBA group when compared to RFA-nCF (33.3% vs 47.7%, adjusted HR 0.60, 95% CI 0.44-0.83, p < 0.01). On the other hand, it was similar between RFA-CF and RFA-nCF groups (43.9% vs 47.7%, adjusted HR 1.01, 95% CI 0.76-1.33, p 0.97). After stratifying patients based on AF type, these findings were only present in patients with paroxysmal AF. CONCLUSION: CBA for paroxysmal AF, in male dominant patients' population, was associated with lower incidence of AF recurrence rate while having a comparable safety profile to RFA independent of the use of CF catheters.

Cocaine Use and Pulmonary Hypertension.

Evidence linking cocaine to the risk of pulmonary hypertension (PH) is limited and inconsistent. We examined whether cocaine use, in the absence of other known causes of PH, was associated with elevated systolic pulmonary artery pressure (sPAP) and increased probability of PH. We compared patients with documented cocaine use to a randomly selected age, sex, and race-matched control group without history of cocaine use. All participants had no known causes of PH and underwent echocardiography for noninvasive estimation of sPAP. We used routinely reported echocardiographic parameters and contemporary guidelines to grade the probability of PH. In 88 patients with documented cocaine use (mean age ± standard deviation 51.7 ± 9.5 years), 33% were women and 89% were of Black race. The commonest route of cocaine use was smoking (74%). Cocaine users compared with the control group had significantly higher sPAP (mean ± standard deviation, 30.1 ± 13.1 vs 22.0 ± 9.8 mm Hg, p <0.001) and greater likelihood of PH (25% vs 10%, p = 0.012). In multivariable analyses adjusted for potential confounders including left ventricular diastolic dysfunction, cocaine use conferred a fivefold greater odds of echocardiographic PH (p = 0.006). Additionally, a stepwise increase in the likelihood of PH was noted across cocaine users with negative or no drug screen on the day of echocardiography to cocaine users with a positive drug screen (multivariable p for trend = 0.008). In conclusion, cocaine use was associated with a higher sPAP and an increased likelihood of echocardiographic PH with a probable acute-on-chronic effect.

An unusual pacing artifact.

Cardiac implantable electronic devices (CIEDs) are widely used in current practice. Analyzing the electrocardiographic patterns of these devices and having knowledge of artifacts is crucial to appropriate CIED management. A 32-year-old female patient presented at the device clinic for a routine follow-up visit. A dual-chamber pacemaker had been implanted 12 years previously for sinus node dysfunction. An initial 12-lead electrocardiogram (ECG) prompted concern due to a cyclical pattern of multiple, rapid pacing stimulus artifacts. Device interrogation revealed normal overall pacemaker function. Turning the pace gain function of the ECG machine off failed to eliminate the artifact. On review of the past medical history, the patient was found to have a prior diagnosis of congenital central hypoventilation syndrome and pulmonary hypertension, for which she underwent insertion of a diaphragmatic pacemaker. Interrogation of the diaphragmatic pacemaker revealed that the programmed parameters correlated with the frequency of the artifact noted on the ECG. In cardiac pacing, a single stimulus artifact of sufficient threshold can enable myocardial capture. Capturing diaphragmatic pacing, however, requires a train of multiple stimuli above the threshold. Thus, an understanding of the pacing configurations of various electrical devices that can potentially interfere with CIEDs is crucial to appropriate patient management.

Outcome of catheter ablation for ventricular tachycardia in patients with ischemic cardiomyopathy: A systematic review and meta-analysis of randomized clinical trials.

BACKGROUND: Current ventricular tachycardia (VT) management in patients with ischemic cardiomyopathy (ICM) includes optimal medical therapy, ICDs device therapy, and antiarrhythmic medications. Data about outcomes of catheter ablation (CA) in these patients is scarce. We aimed to perform a meta-analysis of RCTs to compare outcomes of CA vs conventional management of VT in ICM patients who had ICD. METHODS: A systematic review and meta-analysis of published RCTs between January 1970 and December 2016 were performed. Random effects DerSimonian-Laird risk ratios (RR) were calculated. Sensitivity analyses using fixed-effects summary odds ratios (OR) were performed using Peto model. Outcomes of interest were: all-cause mortality (ACM), cardiovascular death (CVD), CV disease-related hospitalization, VT storms, and ICD shocks. RESULTS: 4 RCTs were identified (521 patients (261 had CA), mean age: 66.4 ±â€¯1.7 years, 91.5% male, mean follow-up: 19 months). No difference observed between VT ablation and conventional management regarding ACM (RR 0.94, 95% CI, 0.66-1.32, p = 0.70) or CVD (RR 0.82, 95% CI, 0.52-1.29, p = 0.39). VT ablation was associated with less CV disease-related hospitalization (RR 0.72, 95% CI, 0.54-0.96, p = 0.02), VT storms (RR 0.71, 95% CI, 0.52-0.97, p = 0.03), and trend towards reducing ICD shocks (RR 0.59, 95% CI, 0.34-1.05, p = 0.07). In sensitivity analysis using fixed-effects OR, CA was associated with significant reduction in ICD shocks. CONCLUSION: In patients with ICM, VT ablation reduced CV disease-related hospitalization, VT storms, and ICD shocks when compared to conventional management with no mortality benefit over a relatively short mean follow-up period.

Comparison of the prognostic value of non-ischaemic fractional flow reserve using intracoronary versus intravenous adenosine.

AIMS: Intracoronary adenosine (ICA) yields similar fractional flow reserve (FFR) results to the "gold standard" of intravenous adenosine (IVA). Whether they have similar prognostic significance is unknown. We therefore sought to study the prognostic value of the route of adenosine administration for the measurement of FFR in deferred coronary lesions in a large, real-world cohort. METHODS AND RESULTS: Five hundred and seventy-six patients with 787 lesions in whom PCI was deferred based on FFR >0.75 were studied. The primary outcome was the first major adverse cardiovascular event (MACE; defined as death, myocardial infarction [MI], or target vessel revascularisation [TVR]), and the secondary outcome was a composite of MI and target vessel failure (TVF). FFR was measured with ICA in 426 lesions and IVA in 361 lesions. Median follow-up duration was 3.2 years (interquartile range: 1.7- 4.6). Propensity-matched cohorts of ICA and IVA were well matched for baseline clinical, angiographic and haemodynamic characteristics. In the propensity-matched cohort, MACE occurred in 23.5% of the ICA group and in 22.3% of the IVA group (p=0.29). On multivariate analysis, acute coronary syndrome, FFR and prior MI/revascularisation were independent predictors of MACE and MI/TVF. The route of adenosine administration was not predictive of MACE or MI/TVF. CONCLUSIONS: ICA and IVA yield similar FFR values and show comparable long-term prognostic utility in a deferred population. These findings provide confirmation that non-ischaemic FFR using a simpler ICA protocol provides prognostic data similar to the gold standard IVA.

Chronic lead malposition diagnosis and management: discussion of two cases and literature review.

Management of lead malposition is crucial to avoid complications and is carried out on case-by-case bases. The 12-lead ECG during pacing and chest X-ray are essential during initial workup and recommended for new patients to the device clinic. Echocardiography and CT scan are important to confirm the location and plan appropriate therapy.

A novel stent inflation protocol improves long-term outcomes compared with rapid inflation/deflation deployment method.

BACKGROUND: High-pressure inflation for coronary stent deployment is universally performed. However, the duration of inflation is variable and does not take into account differences in lesion compliance. We developed a standardized "pressure optimization protocol" (POP) using inflation pressure stability rather than an arbitrary inflation time or angiographic balloon appearance for stent deployment. Whether this approach improves long-term outcomes is unknown. METHODS AND RESULTS: 792 patients who underwent PCI using either rapid inflation/deflation (n = 376) or POP (n = 416) between January 2009 and March 2014 were included. Exclusion criteria included PCI for acute myocardial infarction, in-stent restenosis, chronic total occlusion, left main, and saphenous vein graft lesions. Primary endpoint was target vessel failure [TVF = combined end point of target vessel revascularization (TVR), myocardial infarction, and cardiac death]. Outcomes were analyzed in the entire cohort and in a propensity analysis. Stent implantation using POP with a median follow-up of 1317 days was associated with lower TVF compared with rapid inflation/deflation (10.1 vs. 17.8%, P < 0.0001). This difference was driven by a decrease in TVR (7 vs. 10.6%, P = 0.0016) and cardiac death (2.9 vs. 5.8%, P = 0.017) while there was no difference in myocardial infarction (1 vs. 1.9%, P = 0.19). In the Cox regression model, deployment using POP was the only independent predictor of reduced TVF (HR 0.43; 0.29-0.64; P < 0.0001). In the propensity analysis (330 patients per group) TVF remained lower with POP vs. rapid inflation/deflation (10 vs. 18%, P < 0.0001). CONCLUSIONS: Stent deployment using POP led to reduced TVF compared to rapid I/D. These results recommend this method to improve long-term outcomes. © 2017 Wiley Periodicals, Inc.

Long-Term Prognosis of Deferred Acute Coronary Syndrome Lesions Based on Nonischemic Fractional Flow Reserve.

BACKGROUND: Deferring percutaneous coronary intervention in nonischemic lesions by fractional flow reserve (FFR) is associated with excellent long-term prognosis in patients with stable ischemic heart disease (SIHD). Although FFR is increasingly used for clinical decision making in acute coronary syndrome (ACS) patients with intermediate lesions, its effect on long-term prognosis has not been well established. OBJECTIVES: This study investigated the clinical and prognostic utility of FFR in ACS patients with percutaneous coronary intervention deferred on the basis of nonischemic FFR. METHODS: We studied 206 consecutive ACS patients with 262 intermediate lesions and 370 patients with SIHD (528 lesions) in whom revascularization was deferred on the basis of a nonischemic FFR (>0.75). The primary outcome measure was a composite of myocardial infarction and target vessel failure (major adverse cardiovascular events [MACE]). RESULTS: In the entire cohort, the long-term (3.4 ± 1.6 years) MACE rate was higher in the ACS group than in the SIHD group (23% vs. 11%, p < 0.0001). After propensity score matching (200 patients/group), MACE remained significantly higher (ACS 25% vs. SIHD 12%; p < 0.0001). On Cox proportional hazards analysis for MACE, ACS had a hazard ratio of 2.8 (95% confidence interval: 1.9 to 4.0; p < 0.0001). In both the matched and unmatched cohorts, across all FFR categories, ACS patients had a significantly higher annualized myocardial infarction/target vessel revascularization rate compared with SIHD (p < 0.05). Receiver-operating characteristic analysis identified FFR cutoffs (best predictive accuracy for MACE) of <0.84 for ACS (MACE 21% vs. 36%; p = 0.007) and <0.81 for SIHD (MACE 17% vs. 9%; p = 0.01). CONCLUSIONS: Deferring percutaneous coronary intervention on the basis of nonischemic FFR in patients with an initial presentation of ACS is associated with significantly worse outcomes than SIHD. Caution is warranted in using FFR values derived from patients with SIHD for clinical decision making in ACS patients.

The Effect of Metformin Use on Left Ventricular Ejection Fraction and Mortality Post-Myocardial Infarction.

BACKGROUND: Animal studies showed that the use of metformin after myocardial infarction (MI) resulted in a protective effect on cardiac myocytes. In this study, we examined the effect of metformin in patients with diabetes mellitus (DM) on left ventricular ejection fraction (LVEF) and post-MI mortality. METHODS: We reviewed charts of patients with MI admitted to the UAMS medical center. Baseline characteristics and 12-month follow up data were collected. Patients were classified into three groups: Control group- no DM (n = 464), Metformin group- DM + MI (n = 88) and No-Metformin group- DM + MI (n = 168). First, we compared Metformin and No-Metformin groups to the Control group. Second, we performed propensity-score matching in patients with DM, and compared Metformin to No-Metformin groups. RESULTS: All-cause 30-day and 12-month mortality was significantly higher in the No-Metformin group compared to controls (13.5 vs 9.3% p = 0.03 at 30 days, 23.7 vs 15.9 % p = 0.03 at 12 months). However, all-cause 30-day and 12-month mortality were similar in the Controls and Metformin group (9.3 vs 6.8 % p = 0.93 at 30 days, 15.9 vs 11.4 % p = 0.97 at 12 months). Mean LVEF on presentation (45 % in the three groups) and at follow up (47.84, 46.38 and 43.62 % in Control, Metformin, and No-Metformin groups, respectively) were not statistically different. There were no significant differences in regard to re-hospitalization, re-intervention, new stroke, CHF development, new MI, or identifiable arrhythmias. Metformin was an independent predictor of lower 30-day and 12-month all-cause mortality in patients with DM (HR 0.25, p = 0.02 and HR 0.32, p = 0.01, respectively). In the matched analysis, 30-day all-cause mortality was significantly higher in the No-Metformin compared to the Metformin group (21.1 vs 8.8 %, p = 0.05). However the difference in 12-month all-cause mortality did not reach statistical significance (24.6 vs 15.8 %, p = 0.15). CONCLUSION: This proof-of-concept study shows that use of metformin in patients with DM is associated with lower 30-day all-cause mortality and tendency for a lower 12-month all-cause mortality following MI without discernible improvement in LVEF.