A case of atrial fibrillation complicated by complete atrioventricular block

Atrial fibrillation and complete atrioventricular block are two well-established arrhythmias that can share common aetiologies and risk factors. Although the two arrhythmias can co-exist, only a limited number of cases of atrial fibrillation complicated by complete atrioventricular block have been reported. Correct recognition is essential due to the risk of sudden cardiac death. A 78-year-old female with known atrial fibrillation presented with a 1-week history of shortness of breath, chest tightness and dizziness. On assessment, she was bradycardic with a heart rate of 38 bpm, despite the absence of any rate-limiting medication. Electrocardiography revealed an absence of P waves with a regular ventricular rhythm, consistent with a diagnosis of atrial fibrillation complicated by complete atrioventricular block. This case highlights the diagnostic electrocardiography features of co-existing atrial fibrillation with complete atrioventricular block that are often misinterpreted, leading to a delay in correct diagnosis and initiation of definitive management. Upon diagnosis, it is essential to exclude the reversible causes of complete atrioventricular block before considering permanent pacing. In particular, this includes rate-limiting medications in patients with pre-existing arrhythmias such as atrial fibrillation and electrolyte disturbances.

A 60-Year-Old Woman with a 6-Week History of Shortness of Breath and Intermittent Chest Pain Due to Chronic Thromboembolic Pulmonary Disease Undetected by Computed Tomography Pulmonary Angiography (CTPA) and Diagnosed by Ventilation-Perfusion Imaging

BACKGROUND Chronic thromboembolic pulmonary disease (CTEPD) is the persistent occlusion of pulmonary arteries resulting from 1 or more thrombo-emboli. Its presentation is often non-specific, with exertional dyspnea and fatigue, yet if left undiagnosed risks of chronic thromboembolic pulmonary hypertension and right-sided cardiac failure can ensue. Computed tomography pulmonary angiography (CTPA) and ventilation/perfusion (V/Q) imaging are most commonly utilized for investigating CTEPD. This report is of a 60-year-old woman with a 6-week history of breathlessness and intermittent chest pain due to CTEPD, undetected by CTPA and diagnosed by V/Q imaging. CASE REPORT A 60-year-old woman presented with a 6-week history of breathlessness, intermittent chest pain, and reduced mobility. Her past medical history included chronic obstructive pulmonary disease, pulmonary sarcoidosis, and obesity. Screening tests for infective and ischemic cardiac etiologies were unremarkable. A calculated Wells score was 6, making CTEPD the main differential diagnosis, and she was commenced on therapeutic dose anticoagulation. A CTPA performed on day 2 of admission showed no evidence of acute thromboembolic pulmonary disease or CTEPD. Instead, V/Q scintigraphy on day 6 revealed a perfusion mismatch in the right lung apex, consistent with CTEPD. The patient improved clinically and was discharged on long-term apixaban. CONCLUSIONS A negative CTPA does not necessarily exclude CTEPD. The sensitivity of CTPA for CTEPD is lower than that of V/Q imaging, and can hence lead to false-negative results, as this case highlights. When there is a high clinical suspicion for CTEPD but a negative CTPA study, V/Q imaging should always be undertaken.

The prevalence and course of COVID-19 and the Cardiovascular Diseases

Corona pandemic has infected over 277 million people and has claimed more than 5.4 million lives with recovery of 249 million globally by early 2022. The global case fatality rate ranged from 6-7% in United States, Switzerland, Ireland, 12-14% in Sweden, Spain, Netherlands, United Kingdom, Italy, and 15-16% in France and Belgium among hospitalized and non-hospitalized COVID-19 patients, the prevalence of underlying cardiovascular diseases was 9%. The prevalence of cardiovascular diseases among hospitalized COVID-19 patients and those requiring intensive care unit admission were 23% and 29% respectively. The virus continues to evolve into new formats latest being Delta and Omicron variants. In a multicenter study of 8910 COVID-19 patients from 169 hospitals in Asia, Europe and North America, presence of pre-existing coronary artery disease, chronic heart failure and cardiac arrhythmia was associated with increased mortality of 10.2%, 15.3% and 11.5% respectively, compared with 5-6% mortality in those without the above co-morbidities. The systemic inflammation caused by SARS-CoV-2 could lead to a wide spectrum of cardiovascular complications including acute cardiac injury, acute coronary syndrome, coronary artery dissection, acute myocarditis, cardiomyopathy, chronic heart failure, cardiac arrhythmia, pulmonary embolism, cardiogenic shock, circulatory failure or even cardiac arrest.

UBLED AF (Uninterrupted BLackpool EDoxaban vs Warfarin vs Rivaroxaban in Atrial Fibrillation/Flutter ablation) Study

Aim

Catheter ablation in patients with atrial fibrillation (AF)/atrial flutter carries a risk of thromboembolism and major bleeding. In light of recent prospective trial data on the safety and efficacy of uninterrupted edoxaban in patients undergoing AF/flutter ablation, real-world Data was aimed for validation.

Methods

A total of 228 patients who underwent AF/atrial flutter ablation over 14 months at our centre were retrospectively analyzed. All patients received uninterrupted oral anticoagulation for at least 4 weeks prior to ablation and 3 months post-ablation. Both bleeding and thromboembolic events were assessed at 24 hours comparing patients on warfarin, rivaroxaban and edoxaban.

Results

Mean age of patients were 68.5 +/- 8 years in the warfarin group ( N =86), 63.4 +/- 10.6 years; in the edoxaban group ( N =63) and 62.3 +/- 11.6 years in the rivaroxaban group ( N =79). CHADSVASc scores were 2.43 +/- 1.34, 1.68 +/- 1.34 and 1.64 +/- 1.38 respectively. The mean left atrial sizes were 42.7 +/- 6.8 mm, 42.0 +/- 6 mm and 41.1 +/- 6.5 mm respectively. The study endpoint was death, acute thromboembolism or major bleeding. There was 1 pericardial effusion (1.2%) in the warfarin group, 1 pericardial effusion and 1 transient ischaemic attack (2.5%) in the rivaroxaban group and 1 pericardial effusion needing drainage (1.6%) in the edoxaban group. There were no significant differences in the study endpoints between groups.

Conclusion

This real-world study demonstrated no significant difference in safety and efficacy between uninterrupted edoxaban, warfarin and rivaroxaban in patients undergoing AF/flutter ablation.

His Bundle Pacing – Stand-alone or adjunctive physiological pacing: a systematic review

His-bundle pacing (HBP) appears to be a viable stand-alone or adjunctive physiological pacing therapy in pacemaker dependent patients. It could also serve as an effective adjunct or alternative pacing therapy for heart failure patients who require cardiac resynchronization therapy or pacemaker upgrade. His-bundle pacing has demonstrated improvement of His-Purkinje conduction, left ventricular electrical / mechanical synchronization, and left ventricular ejection fraction (LVEF) compared with right ventricle pacing. Patients who have high pacing dependence and/or LVEF impairment would benefit most from HBP in terms of heart failure hospitalization and LVEF improvement. Mortality benefit has not been consistently demonstrated in latest meta-analysis. The long-term clinical benefit and safety profile of HBP remains to be explored in future studies.  Key words: His bundle pacing, physiologic pacing, upgrade pacing

Adenosine Testing After Atrial Fibrillation Ablation: Systematic Review and Meta-Analysis

BACKGROUND

Adenosine can be used to reveal dormant pulmonary vein (PV) conduction after pulmonary vein isolation (PVI) for the treatment of atrial fibrillation (AF). We performed a systematic review and meta-analysis to assess the impact of adenosine administration in patients undergoing PVI for AF.

METHODS

Meta-analysis of 22 studies was performed to assess the rates of freedom from AF in 1) patients with dormant PV conduction versus patients without dormant PV conduction, and 2) patients given routine adenosine post PVI versus patients not given adenosine. Relative-risks (RR) were calculated using random effects modelling.

RESULTS

In 18 studies, 3038 patients received adenosine and freedom from AF in those patients with dormant PV reconnection was significantly lower (62.9%) compared to patients without PV reconnection (67.2%) (RR 0.87; 95% CI: 0.78-0.98). In seven studies with 3049 patients, the freedom from AF was significantly higher in patients who received adenosine (67%) versus those patients who did not receive adenosine (63%) (RR: 1.11; 95% CI: 1.01-1.22).

CONCLUSIONS

The present study showed clear benefits of adenosine testing for freedom from AF recurrence. Adenosine-guided dormant conduction is associated with higher AF recurrence despite further ablation. Future studies should investigate the optimal methodology, including dosage and waiting time between PVI and adenosine administration.

We Know What the Cardiac Surgeon Did During Last Hybrid Arrhythmia Procedure

Superior vena cava (SVC) is an important source of origin of atrial fibrillation (AF) triggers other than a pulmonary vein. Because of the proximity of SVC-aorta ganglionic plexi to the SVC and the extension of myocardium in the SVC from the right atrium, SVC frequently becomes an important source of ectopic beats initiating AF. The potential complications of SVC isolation may include sinus node injury. Sinus node isolation was observed in a patient who had undergone previous surgical isolation of SVC for AF, while attempting to ablate endocardially, near the superior part of interatrial septum for an atrial tachycardia.

A New 35-mm Short Intra-aortic Balloon Catheter: A Suitable Option Also for Non-Small-Sized Patients?

OBJECTIVE

Visceral ischemia can be a potentially life-threatening complication of intra-aortic balloon pump (IABP) support. A shorter IABP catheter might lead to a reduction of visceral complications. In this animal study, we evaluate the effects of a 35-mL short catheter in comparison with a 40-mL standard-sized catheter.

METHODS

Eighteen healthy swine underwent 120-minute ligation of the left anterior descending coronary artery followed by 6 hours of reperfusion being supported by either a short IABP catheter (short group) (n = 6) or a long IABP catheter (long group) (n = 6) or with no assistance (controls) (n = 6). Hemodynamics, visceral and coronary flows, as well as biochemical markers were evaluated throughout the different phases of the protocol.

RESULTS

Mesenteric flows increased significantly at reperfusion (P < 0.001 both) remaining constant afterward (all, P > 0.05) in the short group, while remaining significantly lower in the long group at the start of reperfusion, remaining constantly lower than the short group and controls (P < 0.001 vs short, P < 0.003 vs controls). In both long and short groups, catheters improved renal flows at reperfusion (P < 0.001 both) without any further variation (P > 0.05). In the short group, the flows were higher during the whole of reperfusion (all, P < 0.05). Intra-aortic balloon pump support improved hemodynamic indices and coronary blood flows during reperfusion to a similar extent in both the small and the long group (P > 0.05).

CONCLUSIONS

The short IABP catheter proved to be as effective as the standard-sized catheter in supporting hemodynamics and coronary circulation. Furthermore, it even improves visceral flows in comparison with conventional IABP catheters.

Surgical ablation in patients undergoing mitral valve surgery: impact of lesion set and surgical techniques on long-term success

AIMS

To assess the results and impact of lesion set and surgical technique on long-term success of surgical ablation during mitral surgery.

METHODS AND RESULTS

The patient population consisted of 685 subjects with persistent and long-standing persistent atrial fibrillation (AF) undergoing cardiac surgery for mitral valve disease as the primary indication and concomitant ablation between January 2003 and January 2012 at three institutions. One hundred and sixty-six underwent unipolar (24.2%), 371 (54.2%) bipolar, and 148 (21.6%) had combined ablation. Median follow-up was 58.4 months (interquartile range 43.3-67.9). To appropriately account for death, a competing risk model was employed to identify predictors of cumulative incidence of recurrent AF among lesion set and surgical techniques. Eight-year freedom from recurrent arrhythmia without antiarrhythmic drugs was 0.60 ± 0.02. Success rate was higher using bipolar radiofrequency (RF) (P < 0.001), after performing mitral isthmus line (P = 0.003) and following the biatrial technique (P < 0.001). Competing risk regression revealed that use of unipolar RF [sub-hazard ratio (SHR) 2.41 (1.52-3.43), P < 0.001], combined unipolar/bipolar ablation [SHR 1.93 (0.89-2.57), P = 0.003] and the absence of right atrial ablation [SHR 2.79 (1.27-3.48), P < 0.001] were predictors of cumulative incidence of long-term recurrence.

CONCLUSIONS

Our experience suggests that the use of bipolar clamp improves long-term results in surgical treatment of AF and that right-sided ablation should be routinely added. Randomized studies are necessary to confirm our findings.

Does sinus rhythm conversion after cardiac surgery affect postoperative health- related quality of life?

Background

We investigated the impact and the predictive value of sinus rhythm at 12 months (SR₁₂) on subscales of three different HrQoL questionnaires: SF-36., EuroQoL and MFI 20.

Methods

Data of 125 cardiac surgery patients with pre-operative AF from our previous randomized trial were used. Based on their rhythm outcome patients were divided in two groups: SR₁₂ or AF at 12 months follow up (non-SR₁₂). All questionnaires were self-administered pre-operatively and at 3 months, 6 months and 12 months after surgery.

Results

Synus rhytm at 12 months was predictive of improvement of SF36- mental score (MS, p = 0.021), Euro-QoL-MS (p = 0.009), VAS (p = 0.006), and MFI 20-MS (p = 0.009). We failed to find any significant interactions between SR₁₂ and any of the other significant risk factors: age <65 years, paroxysmal type of AF and preoperative AF duration <12 months. In contrast, SR₁₂ was not significant in predicting physical score (PS) subscales of any of the questionnaires (all, p > 0.05) which were predicted by age <65 years (SF36-PS, p = 0.029) by paroxysmal type of AF and age <65 years (Euro-QoL-PS, p = 0.017 and p = 0.04, respectively) and by AF duration <12 months, paroxysmal type of AF and age < 65 years (MFI 20-PS, p = 0.019, p = 0.020 and p = 0.015, respectively).

Conclusions

Specific mental-related HrQoL scales are much more sensitive to sinus rhythm conversion. Sinus rithm mantainance shows significant effects on mental scores independently of other cofactors. Successful conversion to sinus rhythm after surgical ablation during cardiac surgery does not significantly affect phisical health related quality of life during 1 year follow up.

The ABLA-BOX: An in Vitro Module of Hybrid Atrial Fibrillation Ablation

Objective

We present the first testing study on the ABLA-BOX, a new in vitro module of hybrid atrial fibrillation ablation.

Methods

ABLA-BOX consists of two chambers that mimic the epicardial and endocardial sides of the heart. The septum between chambers provides catheter access on both sites of the cardiac tissue. A circuit, filled with freshly obtained porcine blood, including a pump, an oxygenator, and a heating device, circulate the blood inside the system. Left atrial fresh tissue is mounted on a tissue holder and magnetically fixed. Epicardial and endocardial catheters are fixed on the catheter holders and blocked with the locker knob. The system allows control of ablation force, flow rate, temperature, and flow pattern.

Results

Epicardial contact force of 100 g and endocardial force of 30 g resulted in larger lesion volumes (P < 0.001), areas (P < 0.001), and lesion diameters (P = 0.03 and P = 0.008), than the combination of 100/20 g. In addition, with a flow rate of 5 L/min, lesion volumes (P = 0.02), areas (P < 0.001), and diameters (both, P < 0.001) were significantly larger in comparison with those of 3 L/min. Furthermore, dimensions (both, P < 0.001), volume (P < 0.001), and area (P < 0.001) of the lesions at a circulating blood temperature of 38.0°C were larger than with a lower blood temperature (36.0°C). Finally, ablations made under stable flow pattern resulted in greater lesion diameters P = 0.04 and P = 0.03) as well as larger volumes (P = 0.02) and areas (P = 0.03) than under turbulent-like flow reproduced with the system rotor set to 400 rpm.

Conclusions

The ABLA-BOX allowed easy hybrid ablation with different setups, which can provide cardiologists and cardiac surgeons with reliable and more valuable insights.

Contact forces during hybrid atrial fibrillation ablation: an in vitro evaluation

PURPOSE

Data on epicardial contact force efficacy in dual epicardial-endocardial atrial fibrillation ablation procedures are lacking. We present an in vitro study on the importance of epicardial and endocardial contact forces during this procedure.

METHODS

The in vitro setup consists of two separate chambers, mimicking the endocardial and epicardial sides of the heart. A circuit, including a pump and a heat exchanger, circulates porcine blood through the endocardial chamber. A septum, with a cut out, allows the placement of a magnetically fixed tissue holder, securing porcine atrial tissue, in the middle of both chambers. Two trocars provide access to the epicardium and endocardium. Force transducers mounted on both catheter holders allow real-time contact force monitoring, while a railing system allows controlled contact force adjustment. We histologically assessed different combinations of epi-endocardial radiofrequency ablation contact forces using porcine atria, evaluating the ablation's diameters, area, and volume.

RESULTS

An epicardial ablation with forces of 100 or 300 g, followed by an endocardial ablation with a force of 20 g did not achieve transmurality. Increasing endocardial forces to 30 and 40 g combined with an epicardial force ranging from 100 to 300 and 500 g led to transmurality with significant increases in lesion's diameters, area, and volumes.

CONCLUSIONS

Increased endocardial contact forces led to larger ablation lesions regardless of standard epicardial pressure forces. In order to gain transmurality in a model of a combined epicardial-endocardial procedure, a minimal endocardial force of 30 g combined with an epicardial force of 100 g is necessary.

The symbiosis of contact force catheter use for hybrid ablation for atrial fibrillation

Objective

Reconduction across an ablation line is a common reason for arrhythmia recurrence over time. The hybrid procedure combines epicardial ablation of the pulmonary vein (PV) and creation of a box lesion with endocardial touch-ups for any electrical gaps. A high contact force (CF) between the ablation tip and cardiac tissue may increase the risk of thrombus formation, catheter tip charring, steam pop formation, and even cardiac perforation. CF monitoring is a significant new parameter for titration of the CF for creating an adequate lesion.

Methods

Thirty-eight consecutive patients underwent epicardial ablation using bipolar radiofrequency devices. After checking electrical bidirectional block of the ablation lines, an endocardial CF catheter was used for further ablation (if needed) to complete the isolation of PVs, box lesion, cavotricuspid isthmus (CTI), and complex fractionated atrial electrograms (CFAE).

Results

Endocardial touch-up was needed for 2 PVs (1.3 %) and 10 (26.3 %) box lesions. It was also used for the CTI line in 7 (18.4 %) patients, atrial tachycardia in 3 (7.9 %) patients, and additional CFAE ablation in 17 (44.7 %) patients. All 5 patients with arrhythmia recurrence had a mean CF < 10 g (p = 0.03). Procedure duration was significantly shorter in the CF group (223 ± 57 vs. 256 ± 60 min, p = 0.03) compared with control group.

Conclusion

Use of CF catheters is safe, feasible, and complementary to a hybrid procedure setup for atrial fibrillation ablation. Its real-time monitoring may predict future arrhythmia recurrence, and decrease procedure time.

Catheter ablation for atrial fibrillation in hypertrophic cardiomyopathy patients: a systematic review

PURPOSE

The primary aim of this systematic review was to assess the efficacy of catheter ablation of atrial fibrillation (AF) in patients with hypertrophic cardiomyopathy (HCM). Differentiation based off catheter ablation modalities was not considered due to the limited scope of the current field. Studies that employed alcohol septal ablation for the treatment of AF in HCM patients were excluded as were abstracts, case reports, conference presentations, editorials, reviews, and expert opinions

METHODS

Electronic searches were performed in six databases from their inception until January 2014. Relevant studies regarding catheter ablation for AF in HCM populations were identified. Data was extracted and analyzed according to pre-defined clinical endpoints

RESULTS

A review was undertaken of eight studies in which 241 HCM patients underwent catheter ablation for AF. Overall AF-free survival at last follow-up ranged from 47 to 77% (64-67%). Sinus rhythm was maintained at last follow-up in 47-82% (median 64-67%). AF recurrence ranged from 0 to 66% (median 35-40%).

CONCLUSION

A review of the current evidence suggests that catheter ablation of AF in HCM patients is effective with suitable efficacy and is justified in select patients. Future adequately powered randomized studies should be undertaken aimed at addressing long-term efficacy and complications associated with procedural outcomes.

Adenosine testing after second-generation cryoballoon ablation (ATSCA) study improves clinical success rate for atrial fibrillation

AIMS

Adenosine administration after pulmonary vein (PV) isolation using radiofrequency, laser, and cryoablation can cause acute recovery of conduction to the PVs and predict atrial fibrillation (AF) recurrence. This study evaluates whether ablation of dormant potentials post-adenosine administration following second-generation cryoballoon (CB-2G) ablation may improve the success rate for AF.

METHODS AND RESULTS

In 45 of 90 patients after a waiting period of 30 min, a bolus 15-21 mg of adenosine was administered followed by rapid saline flush. The response was assessed for each PV using a circular octapolar catheter. If needed, further ablation using a cryoballoon and/or cryocatheter was performed until no reconduction was observed after repeat adenosine administration. The remaining 45 patients did not receive adenosine after the procedure. Acute PV isolation was achieved in 352 of 358 PVs (98.3%) of 86 of 90 patients (95.6%) using CB-2G. The adenosine group showed dormant reconduction in 5 of 45 patients (11%), 8 of 179 PVs (4.5%), including 1 left superior pulmonary vein, 3 left inferior pulmonary vein, 1 right superior pulmonary vein, and 3 right inferior pulmonary vein. The success rate for adenosine and without adenosine group was 84 and 79%, respectively, after a mean follow-up of 397 ± 47 and 349 ± 66 days, without any AF recurrence in patients in whom adenosine-induced dormant conduction was ablated.

CONCLUSION

Adenosine testing after second-generation cryoballoon ablation study showed that reablation of initially isolated PVs increases the clinical success rate for AF.

Headache during cryoballoon ablation for atrial fibrillation

AIMS

Headache has been reported to occur during cryoballoon ablation for atrial fibrillation (AF). No study has systematically analysed this phenomenon.

METHODS AND RESULTS

Twenty consecutive patients with symptomatic AF underwent cryoballoon ablation without sedation. Headache was evaluated before, during, and after the first cryoapplication in every pulmonary vein (PV) using a visual representation of a head for location of the headache, a numerical rating scale (NRS) for measuring pain intensity and the short-form McGill pain questionnaire (MPQ) for qualitative analysis of pain. The order in which the PVs were ablated was randomized. Sixteen (80%) patients perceived mainly frontal headache during cryoablation. The overall NRS scores were significantly higher during (5.1 ± 1.7), compared with before (2.7 ± 1.4), and after (3.5 ± 2.2) a cryoapplication (P < 0.05). The NRS score was significantly higher during ablation of the first PV. The intensity of the perceived headache was not related to the temperature reached 150 s after initiation of a cryoapplication (P = 0.81). Of the MPQ, three sensory adjectives and one affective adjective averaged between scores 1 and 2, representing mild-to-moderate severity of pain.

CONCLUSION

The majority of patients treated by balloon cryoablation experienced headache during a cryoapplication. There was no correlation between the temperature reached during a cryoballoon freeze and the intensity of the headache. Cryoballoon ablation of the first PV was significantly more painful than the remaining PVs.