Heart failure and atrial fibrillation: Is atrial fibrillation ablation in heart failure pointless or mandatory?

A vast amount of now well-established clinical and epidemiological data indicates a close, interdependent, and symbiotic association between atrial fibrillation (AF) and heart failure (HF). Both AF and HF, when co-exist in a patient, have serious treatment and prognostic implications. Based on the prevailing knowledge of the topic, various societies have issued a number of guidelines regarding the management of patients with AF and HF. Overall, it is the rhythm control strategy that has shown beneficial effect over the rate control strategy with improvement in symptoms of AF and HF. While antiarrhythmic drugs (AADs) and catheter ablation (CA) may be utilized as rhythm control strategy for AF, both AADs and CA have limitations of their own. Furthermore, with the progress made in various pharmacotherapeutic agents in HF, one could question the utility of CA in HF (i.e., whether ablation is mandatory or pointless in patients who have HF). The purpose of this review is to discuss this very point, focusing on the beneficial, neutral, or detrimental outcome of CA based on the category and class of HF.

Are antiarrhythmic agents indicated in premature ventricular complex-induced cardiomyopathy and when?

INTRODUCTION: Premature ventricular complexes (PVCs) are the most common ventricular arrhythmia that are encountered in the clinical practice. Recent data suggests that high PVC burden may lead to the development of PVC-induced cardiomyopathy (PVC-CM) even in patients without structural heart disease. Treatment for effective suppression of PVCs, can reverse PVC-CM. Both antiarrhythmic drugs (AADs) and catheter ablation (CA) are recognized treatment modalities for any cardiac arrhythmias. However, with increasing preference of CA, the role of AADs needs further defining regarding their efficacy, safety, indications and patient selection to treat PVC-CM. METHODS: To ascertain the role of AADs to treat PVC-CM; whether they are indicated to treat PVC-CM, and if so, when, we interrogated PubMed and other search engines for English language publications with key words premature ventricular complexes (PVCs), cardiomyopathy, anti-arrhythmic drugs, catheter ablation, and pharmacological agents. All publications were carefully reviewed and scrutinized by the authors for their inclusion in the review paper. For illustration of cases, ethical standard was observed as per the 1975 Declaration of Helsinki, and the patient was treated as per the prevailing standard of care. Informed consent was obtained from the patient for conducting the ablation procedure. RESULTS: Our literature search specifically the pharmacological treatment of PVC-CM with AADs revealed significant paradigm shift in treatment approach for PVCs and PVC-induced cardiomyopathy. No major large, randomized control trials of AADs versus CA for PVC-CM were found. We found that beta-blockers and calcium channel blockers are particularly effective in the treatment of PVCs originating from right ventricular outflow tract. For Class Ic AADs - flecainide and propafenone, small clinical studies showed Class Ic AADs to be effective in PVC suppression, but their usage was not recommended in patients with significant coronary artery disease. Mexiletine was found to have modest effect on PVC suppression. Studies showed sotalol to significantly reduce PVCs frequency in patients receiving both low and high doses. Studies also showed amiodarone to have higher successful PVC suppression, but not recommended as a first-line treatment for patients with idiopathic PVCs in the absence of symptoms and left ventricular dysfunction. For dronedarone, no major clinical data were available. CONCLUSIONS: Based on the available data in the literature, we conclude that AADs play important role in the treatment of PVC-induced cardiomyopathy. However, appropriate patient selection criteria are vitally important, and in general terms AADs are indicated or polymorphic PVCs, epicardial PVCs; and when CA procedure is contraindicated, or not feasible or failed.

Open-window mapping for ablation of Wolff-Parkinson-White syndrome related hemodynamically unstable tachycardia.

During catheter ablation (CA) of tachycardia, conventional point-by-point mapping may be hindered due to hemodynamic instability. We performed open-window mapping (CARTO, Biosense Webster, USA) in a patient who developed hemodynamic instability during orthodromic atrioventricular reciprocating tachycardia (AVRT) and unwarranted induction of AVRT during attempts to map accessory pathway (AP) with ventricular pacing. With over 11,000 points acquired rapidly, the system accurately identified AP at the mitral valve (MV) annulus where the application of single radiofrequency (RF) lesion promptly eliminated AP's conduction. Our case illustrates the utility of open-window mapping for the ablation of AVRT.

Persistently abnormal device-detected thoracic impedance and OptiVol fluid index related to breast reconstruction surgery.

With significant correlation shown between intrathoracic impedance and intrathoracic fluid volume, the utility of OptiVol fluid index (Medtronic, Minneapolis, MN, USA) in the management of patients with heart failure has been well-described. Although intrathoracic impedance is mainly affected by the changes in the intrathoracic fluid volume, a "false-positive" OptiVol fluid index can occur in the absence of overt congestive heart failure. We present a case of false positive Optivol fluid index elevation in a woman following breast reconstruction surgery.

Implications of "slower" ventricular tachycardia on clinical management and detection and therapy function of implantable cardioverter defibrillators.

Sophisticated dual-chamber atrioventricular and rate-responsive pacing therapies, cardiac resynchronization therapy (CRT), detection and therapies for ventricular tachycardia and fibrillation (VT/VF) form some major components of multitask functions of current implantable cardioverter defibrillators (ICDs). Appropriate programming of these devices is necessary for them to perform all such tasks precisely. In this report, we describe a case of a patient with Chagas cardiomyopathy with marked cardiomegaly, scarred ventricles, prior epicardial and endocardial ablations and on antiarrhythmic pharmacotherapy for VT, who presented with symptomatic wide complex tachycardia at a slower rate than definition of VT, and in whom programming for detection and therapy for "slow" VT could not be performed due to default technological limitation of the CRT-D.

One year outcomes of atrial fibrillation ablation: Contemporary analysis of the United States Nationwide Readmission Database.

BACKGROUND: Data on long-term outcomes of catheter ablation (CA) for atrial fibrillation (AF) in outside of clinical trials settings are sparse. OBJECTIVE: We aimed to assess outcomes and readmissions at 1 year following admission for CA for AF. METHODS: Utilizing the Nationwide Readmissions Database (2016-2018), we identified patients with CA among all patients with a primary admission diagnosis of AF, and a control group by propensity score match adjusted for age, sex, comorbidities, CHA2DS2-VASc scores, and the hospital characteristics. The primary outcome was a composite of unplanned heart failure (HF), AF and stroke-related readmissions, and death at 1 year, and secondary outcomes were hospital outcomes and all-cause readmission rates. RESULTS: The study cohort consisted of 29,771 patients undergoing CA and 63,988 controls. Patients undergoing CA were younger with lower CHA2DS2-VASc scores and less comorbidities. Over a follow-up of 170 ±1.1 days, the primary outcome occurred in 5.2% in CA group and 6.0% of controls (hazard ratio [HR] and 95% confidence interval [CI]: 0.86 [0.76-0.94], p = .002). CA affected AF and stroke related readmission, but showed no effect on HF and mortality outcome. Male sex (HR: 0.83 [0.74-0.94], p = .03), younger age (HR: 0.71 [0.61-0.83], p < .001], and lower CHA2DS2-VASc scores (HR: 0.68 [0.55-0.84], p < .001) were associated with lower risk of primary outcome with CA. CONCLUSION: In this study, CA for AF was associated with significantly lower AF and stroke-related admissions, but not to HF or all-cause readmission. Better outcomes were seen among males, younger patients, and in patients with less comorbidities and low CHA2DS2-VASc scores.

Implantable cardioverter defibrillator shocks from ventricular tachyarrhythmias in patients with ischemic heart disease: Preventative measures, shortcomings, cost-effectiveness, and global practice perspectives.

Implantable cardioverter defibrillators (ICDs) have proven to be life-saving devices in patients with ischemic cardiomyopathy (ICM) who are prone to develop ventricular tachycardia (VT) and fibrillation (VF). Antiarrhythmic drugs (AADs) are commonly prescribed in many such patients with ICDs to treat and prevent different forms of arrhythmias in clinical practice. When these patients experience recurrent monomorphic VT despite chronic AADs therapy, or when AAD therapy is contraindicated or not tolerated, and VT storm is refractory to AAD therapy, catheter ablation constitute guideline-based class I indication of treatment. However, what should be the most appropriate strategy to prevent first ICD shock or subsequent multiple shocks from VT/VF in patients with ICM who undergo ICD implantation without prior incidence of cardiac arrest, remains debatable. The purpose of this review is to discuss preventative aspects of ICD shocks for VT and the shortcomings of these measures along with the cost-effectiveness and global perspectives based on the current knowledge of the topic.

Alterations in atrial electrogram amplitude as steady sinus rhythm transitions to paroxysmal atrial fibrillation during continuous monitoring in patients with implantable cardiac devices: Insights from the IMPACT study.

OBJECTIVES: We aimed to evaluate whether device measured amplitudes of atrial electrogram (AEGM) would change when measured in sinus rhythm (SR) transitioning to paroxysmal atrial fibrillation (AF) from previous steady SR, and significance of such change. METHODS: From the IMPACT trial's database we selected two groups; (A) those who developed AF (n = 164), and (B) propensity-matched control (n = 459) who stayed in SR during continuous Home Monitoring (HM) to compare AEGMs amplitudes at baseline SR and transition phase. RESULTS: During 420.0 ± 349.2 days (mean ± SD) from first postenrollment HM transmission to AF event transmission in Group A, and corresponding 515.3 ± 407.0 days in Group B, baseline and transition AEGM amplitude were 2.88 ± 1.146 and 2.74 ± 1.186 mV, respectively, for Group A (p = .1), and 2.88 ± 1.155 and 2.79 ± 1.145, respectively, for Group B (p < .005). Comparison of differences of AEGM amplitude, 0.14 ± 1.072 mV in Group A and 0.09 ± 0.893 mV in Group B were insignificant (p = .3). Age, sex, and hypertension identified as confounders had no association to AEGM changes (p = NS). CONCLUSIONS: Independent of age, sex, and hypertension, AEGMs amplitudes decline over a long period of time in patients with defibrillators and substrate for AF. The significance of such change remains unclear as it occurs whether patients develop AF or not, but raises a possibility of progressive atrial myopathy that patients with substrate for AF may be predisposed to.

Safety and complications of catheter ablation for atrial fibrillation: Predictors of complications from an updated analysis the National Inpatient Database.

BACKGROUND: Catheter ablation is increasingly employed in the management of atrial fibrillation (AF). Data regarding safety of ablation of AF is largely derived from controlled clinical trials. OBJECTIVES: The aim of this study was to analyze safety and complications of AF ablation performed in a "real world" setting outside of clinical trials, and obtain insights on predictors of complications. METHODS: We utilized the National Inpatient Sample database, to identify all patients who underwent AF ablations between 2015 and 2017 using International Classification of Disease-Tenth revision codes. Complications were defined as per the Agency for Health Care Research and Quality Guidelines. Statistical tests including multivariate logistic regression were performed to determine predictors of complications. RESULTS: Among 14,875 cases of AF ablation between 2015 and 2017, a total of 1884 complications were identified among 1080 (7.2%) patients. Patients with complications were likely to be older and female with a higher burden of comorbidities. A 27% increase in complications was observed from 2015 to 2017, driven by an increase in pericardial complications. Multivariate regression analysis revealed that pulmonary hypertension (adjusted odds ratio [aOR]: 1.99, p = .041) and chronic kidney disease (CKD; aOR: 1.67, p = .024), were independent predictors of complications. Centers with higher procedural volumes were associated with lower complication rates. CONCLUSIONS: Complication rates related to AF ablations remain substantially high. Presence of pulmonary hypertension and CKD are predictive of higher procedural complications. Furthermore, hospital procedure volume is an important factor that correlates with complication rates.

Pacing to prevent atrial fibrillation.

PURPOSE OF REVIEW: Pacemakers are frequently implanted in patients with atrial fibrillation. Many patients with pacemakers also develop atrial fibrillation. Over a period of time, through many studies on different pacing modes, sites, and algorithms, significant insights have been gained in the field of treatment and prevention of atrial fibrillation. The purpose of this review is to discuss some aspects of the scientific basis, current standards and possible future research related to cardiac pacing for prevention of atrial fibrillation. RECENT FINDINGS: Trials involving pacing at the alternative pacing site per se or in combination with specific algorithms for prevention of atrial fibrillation have not shown consistent results. Recently, a new generation of antitachycardia pacing therapies has brought on a new optimism with promising outcome data of reduction in permanent atrial fibrillation, cardiovascular hospitalizations, and mortality. SUMMARY: Multiple trials and clinical observational studies of different pacing methods and algorithms, with the exception of newer therapies in conjunction with atrial pacing algorithms, have not been shown to prevent atrial fibrillation. Hence, while permanent pacing is indicated for sinus node dysfunction and conduction abnormalities in patients with or without atrial fibrillation, the prevailing data in the literature does not support implantation of a permanent pacemaker for prevention of atrial fibrillation per se.

Role of insertable cardiac monitors in anticoagulation therapy in patients with atrial fibrillation at high risk of bleeding.

AIMS: We aimed to ascertain whether an insertable cardiac monitor (ICM)-guided rhythm-control strategy and assessment of atrial fibrillation (AF) burden may allow safe withdrawal and obviate long-term use of oral anticoagulants (OACs) in AF patients at high bleeding risk. METHODS AND RESULTS: We implanted ICMs in 70 patients with AF with high risk of stroke (CHADS2 ≥2, CHA2DS2-VASc score ≥2) and bleeding (HAS-BLED score ≥3) after restoration of normal sinus rhythm (NSR) for continuous rhythm monitoring and optimization of antiarrhythmic drugs (AADs) when necessary. Patients were categorized into: (i) Group A (NSR/low AF burden, <1%), (ii) Group B (moderate/variable AF burden), and (iii) Group C (high AF burden, always AF). At patients' insistence, OACs were discontinued after proper counselling only if they maintained NSR/low AF burden for ≥3 consecutive months. All patients (age 73.3 ± 11.7 years; 53% male) were followed clinically and with ICM monitoring for 23.5 ± 10.5 months for outcomes including stroke, bleeding, death, device malfunction or infection, and AADs' adverse effects. Patients in Group A (n = 43), Group B (n = 20), and Group C (n = 7) had similar CHADS2 (2.09 ± 0.65, 2.05 ± 0.51, and 2.14 ± 0.38, respectively), CHA2DS2-VASc (3.05 ± 1.05, 2.85 ± 0.99, and 2.42 ± 0.53, respectively), and HAS-BLED (3.02 ± 1.01, 3.40 ± 0.68, and 3.00 ± 0.58, respectively) scores (P > 0.05). In 53 (76%) patients (Group A = 41 and Group B = 12) who maintained NSR/low AF burden, OACs were discontinued without adverse events. Severe bleeding occurred in 4 of 17 (24%) patients who remained on OACs. CONCLUSION: In AF patients with high bleeding risk, ICM-guided rhythm control with AADs and assessment of AF burden may allow safe discontinuation of OACs.

Atrial Tachycardias After "Multiple" Previous Ablations for Tachyarrhythmias: Treatment by Anti-arrhythmic Drugs or Additional Ablation?

Pulmonary vein (PV) isolation (PVI) ablation as the first-line therapy for atrial fibrillation (AF) and repeat PVIs for patients who had symptomatic improvement with the index PVI but who develop AF recurrence are directed by practice guidelines. How many catheter ablation (CA) procedures constitute the definition of "multiple" ablations is not known. Whether atrial tachyarrhythmias (AF, atrial tachycardia [AT], atrial flutter [AFL]) that occur post-ablation are due entirely to the proarrhythmic effects of CA or a continuum of the arrhythmia spectrum from the underlying atriopathy is debatable. Herein, we describe a case of a 65-year-old man with a CHA2DS2-VASc score of 5 points who suffered from atrial tachyarrhythmias for which seven CA procedures were performed. Because of symptomatic and drug-refractory AT/AFL that failed cardioversions, he requested another ablation procedure. During the eighth procedure, high-density three-dimensional electroanatomic mapping, including Coherent and Ripple mapping (CARTO® 3; Biosense Webster, Diamond Bar, CA, USA), of AT/AFL was performed. Small discrete areas of relatively viable tissue within an extensively scarred left atrium and a macro-re-entrant circuit with early-meets-late activation between the left atrial anterior wall and the right superior PV were found. Radiofrequency ablation performed at this site resulted in the termination of the tachycardia, and bidirectional conduction block across the line was achieved. On clinical follow-ups and rhythm monitoring by an implantable loop recorder, the patient remained in sinus rhythm with significant clinical improvement. Our case suggests that, in patients with prior multiple CAs, additional clinically indicated ablation should be performed using high-density mapping to accurately identify arrhythmia mechanisms, elucidate the disease substrate, and restore the sinus rhythm successfully.

Erector Spinae Plane Block Decreases Narcotic Requirements in Patients Undergoing Subcutaneous Implantable Cardioverter-defibrillator Placement Under Sedation.

Providing adequate analgesia perioperatively during subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation can be a challenge. The objective of our study was to assess the efficacy and safety of the erector spinae plane (ESP) block technique in providing analgesia and minimizing the risk of opioid use in high-risk patient populations. We enrolled consecutive patients >18 years of age undergoing S-ICD implantation from February 2020 to February 2022 at our center prospectively. Patients were randomly assigned to receive the ESP block or traditional wound infiltration. A total of 24 patients were enrolled, including 13 patients randomized to ESP block and 11 patients as controls who received only wound infiltration. The primary outcome assessed was the overall use of perioperative analgesic medications in the ESP block group versus the surgical wound infiltration group. A significant reduction in intraoperative fentanyl use was observed [median ([interquartile range]) in the ESP block group (0 [0-50] µg) compared to the wound infiltration block group (75 [50-100] µg) (P = .001). The overall postoperative day (POD) 0 fentanyl use was also significantly decreased (75 [50-100] µg) in the ESP block group compared to the surgical wound infiltration group (100 [87.5-150] µg) (P = .049). There was also a trend of decreased POD 0 oxycodone-acetaminophen use. Finally, the number of days to discharge was less in the ESP block group. These results indicate that ESP block is an innovative, safe, and effective technique that decreases intraoperative and postoperative opioid consumption and may be a useful adjunct pain-management technique in these high-risk patients. Larger studies are needed to further validate its use.

Reuse of explanted, resterilized implantable cardioverter-defibrillators: a cohort study.

BACKGROUND: Implantable cardioverter-defibrillators (ICDs) often have clinically useful battery life remaining when explanted because of upgrades, infection, or patient death. OBJECTIVE: To show that explanted ICDs can be resterilized and reused. DESIGN: Retrospective cohort study. SETTING: Multicenter ICD acquisition and single-center ICD reimplantation. PATIENTS: Indigent persons in India who had class I indications for cardiac resynchronization therapy with an ICD and were unable to afford such a device. MEASUREMENTS: Device longevity after reimplantation, device-related complications, number of appropriate therapies, patient clinical characteristics, and deaths. RESULTS: Eighty-one consecutive consenting patients (mean age, 52.6 years; 66 male patients) received 106 explanted devices. Twenty-two patients received a second device and 3 patients received a third device after the prior one reached replacement voltage. Mean time to ICD replacement was 1287.4 days. Follow-up data were available for 75 of 81 (92.6%) patients. Mean follow-up duration for all devices was 824.9 days. No infectious complications occurred; 1 lead dislodgement and 1 lead fracture required repeated surgery. Appropriate therapy (shocks or antitachycardia pacing) was delivered by 64 of 106 (60.4%) devices in 44 of 81 (54.3%) patients. Nine of 81 (11.1%) patients died; mean time from implantation to death was 771.3 days. LIMITATIONS: This is a retrospective report of a single-center experience with a modest number of patients and devices. Follow-up data were missing for 6 patients. No records were kept of the number of devices obtained through postmortem versus antemortem explantation or whether explantation was due to infection or upgrade. Complete data were not available on exact battery voltage at the time of reimplantation, left ventricular ejection fraction, or number of inappropriate shocks. A control group was not possible. CONCLUSION: Explanted ICDs with 3 or more years of estimated remaining battery life can be reused after they are cleaned and resterilized. These devices functioned normally and delivered life-saving therapies, without an increased risk for complications. These preliminary data deserve further validation and, if confirmed, could have important societal and economic implications. PRIMARY FUNDING SOURCE: None.

Nodal and infranodal atrioventricular conduction block: electrophysiological basis to correlate the ECG findings.

A 68-year-old woman with a history of dilated non-ischemic cardiomyopathy presented with syncope. The index ECG showed sinus rhythm with left bundle branch block. On telemetry episodes of sinus rhythm with narrower QRS complexes conduced in 2:1 pattern were noted. Invasive electrophysiological study was performed to determine cause of syncope. Normal conduction up to the AV node with an AH interval of 79 ms (normal = 55-125 ms) was observed. However, every alternate sinus beat was blocked after the inscription of His deflection (infra-Hisian block). The narrow beats conducted through the His bundle with HV intervals of 54 ms (normal = 35-55 ms). When 1:1 conduction resumed further abnormality of the His-Purkinje conduction system became evident with a QRS morphology that of an LBBB and prolongation of HV interval (HV = 96 ms). Criteria to differentiate nodal versus infranodal block based on electrophysiological properties of the nodal and infranodal system are discussed.

Kinase Inhibitors and Atrial Fibrillation: Mechanisms of Action and Clinical Implications.

Recent advances have significantly expanded the options of available therapeutics for cancer treatment, including novel targeted cancer therapies. Within this broad category of targeted therapies is the class of kinase inhibitors (KIs), which target kinases that have undergone aberrant activation in cancerous cells. Although KIs have shown a benefit in treating various forms of malignancy, they have also been shown to cause a wide array of cardiovascular toxicities, with cardiac arrhythmias, in particular atrial fibrillation (AF), being 1 of the predominant side effects. The occurrence of AF in patients undergoing cancer treatment can complicate the treatment approach and poses unique clinical challenges. The association of KIs and AF has led to new research aimed at trying to elucidate the underlying mechanisms. Furthermore, there are unique considerations to treating KI-induced AF because of the anticoagulant properties of some KIs as well as drug-drug interactions with KIs and some cardiovascular medications. Here, we review the current literature pertaining to KI-induced AF.

Outpatient initiation of dofetilide: insights from the complexities of atrial fibrillation management during the COVID-19 lockdown.

BACKGROUND: At peak COVID-19 lockdown, patients with symptomatic atrial fibrillation (AF) were faced with an equipoise between a palliative rate-control versus cautious rhythm-control strategy, including hospitalization for initiation of antiarrhythmic drug/s (AADs) and cardiac procedures which was impossible due to hospitalization restrictions. OBJECTIVES: We aimed to evaluate the efficacy and safety of outpatient initiation of dofetilide in patients with AF using cardiac implantable electronic devices (CIEDs) for rhythm and QTc interval monitoring. METHODS: Adult patients with symptomatic AF with prior failure or intolerance to other AADs were enrolled if they were willing to in-office insertion of implantable loop recorders or already implanted with pacemakers or defibrillators capable of remote monitoring. Exclusion criteria were known medical contraindications of dofetilide and unable to provide consent. After making a shared management decision, dofetilide was initiated in a physician office, and rhythm and QTc intervals were monitored by ECGs and CIEDs. Patients were followed to assess the efficacy and safety of the treatment. RESULTS: The study cohort comprised of 30 patients, age 76 ± 7 years (mean ± standard deviation), 10 female (33%), CHA2DS2-VASc score 3.25 ± 1.3, ejection fraction 63.45% ± 8.52, and QTc interval 431.68 ± 45.09 ms. From 22 (73%) patients in AF at presentation, SR was restored in 14 (64%) patients after 4 doses of dofetilide. At 46 ± 59 days of follow-up, maintenance of SR in total 22 (73%) patients without cardiac adverse effects was accomplished. CONCLUSION: Effective and safe outpatient initiation of dofetilide during the extenuating circumstance of COVID-19 lockdown was possible in patients with AF who had CIEDs.