Cannon A wave validation as a diagnostic tool in paroxysmal supraventricular tachycardias

OBJECTIVE

The presence of cannon A waves, the so called "frog sign", has traditionally been considered diagnostic of atrioventricular nodal re-entrant tachycardia (AVNRT). Nevertheless, it has never been systematically evaluated. The aim of this study is to assess the independent diagnostic utility of cannon A waves in the differential diagnosis of supraventricular tachycardias (SVTs).

METHODS

We prospectively included 100 patients who underwent an electrophysiology (EP) study for SVT. The right jugular venous pulse was recorded during the study. In 61 patients, invasive central venous pressure (CVP) was registered as well. CVP increase is thought to be related with the timing between atria and ventricle depolarization; two groups were prespecified, the short VA interval tachycardias (including typical AVNRT and atrioventricular reciprocating tachycardia (AVRT) mediated by a septal accessory pathway) and the long VA interval tachycardias (including atypical AVNRT and AVRT mediated by a left free wall accessory pathway).

RESULTS

The relationship between cannon A waves and AVNRT did not reach the statistical significance (OR: 3.01; p = .058); On the other hand, it was clearly associated with the final diagnosis of a short VA interval tachycardia (OR: 10.21; p < .001). CVP increase showed an inversely proportional relationship with the VA interval during tachycardia (b = -.020; p < .001). CVP increase was larger in cases of AVNRT (4.0 mmHg vs. 1.2 mmHg; p < .001) and short VA interval tachycardias (3.9 mmHg vs. 1.2 mmHg; p < .001).

CONCLUSION

The presence of cannon A waves is associated with the final diagnosis of short VA interval tachycardias.

Demonstration of differential ventricular overdrive pacing during long RP' supraventricular tachycardia

We described the differential ventricular overdrive pacing during long RP' supraventricular tachycardia and discussed about its response leading to the dianosis.

Rediscover the predictive capacity of B-type natriuretic peptide applied to neonatal supraventricular tachycardia

BACKGROUND

Supraventricular tachycardia (SVT) is one of the most common non-benign arrhythmias in neonates, potentially leading to cardiac decompensation. This study investigated the early risk factors of acute heart failure (AHF) secondary to SVT in neonates, and explored their value in guiding the selection of effective anti-arrhythmic treatment.

METHODS

A total of 43 newborns diagnosed with and treated for SVT between January 2017 and December 2022 were analyzed. According to the presence of AHF after restoring sinus rhythm in newborns with SVT, they were divided into SVT with AHF group and SVT without AHF group. Clinical data and anti-arrhythmic therapies were analyzed. Risk factors of AHF secondary to SVT in neonates were determined using logistic regression. The cut-off value for predictors of AHF secondary to SVT and demanding of a second-line anti-arrhythmic treatment was determined through receiver operating characteristic (ROC) analysis.

RESULTS

Time to initial control of tachycardia > 24 h, hyperkalemia, anemia, and plasma B-type natriuretic peptide (BNP) were identified as risk factors of AHF secondary to SVT in neonates. BNP exhibited AUC of 0.80 in predicting AHF, and BNP > 2460.5pg/ml (OR 2.28, 95% CI 1.27 ~ 45.39, P = 0.03) was an independent predictor, yielding sensitivity of 70.6% and specificity of 84.6%. Neonates with BNP > 2460.5pg/ml (37.5% versus 7.4%, P = 0.04) had a higher demand for a second line anti-arrhythmic treatment to terminate SVT, with sensitivity and specificity for BNP in predicting at 75.0%, 71.4%, respectively.

CONCLUSIONS

BNP could be used to predict an incident of AHF secondary to SVT and a demand of second-line anti-arrhythmic treatment to promptly terminate SVT and prevent decompensation in neonates.

Anteroseptal accessory pathways: Killing one bird with two stones

BACKGROUND AND AIMS

Ablation of anteroseptal accessory pathways (AS-AP) is challenging, with lower success and more complications compared to other APs. AS-APs can be successfully ablated from the right atrium (RA) or the aortic valve's noncoronary cusp (NCC). We report two patients who required a hybrid ablation approach to achieve successful abolition of both anterograde and retrograde AS-AP conduction.

METHODS AND RESULTS

A 21-year-old female with supraventricular tachycardia (SVT) and pre-excitation on electrocardiogram (ECG) underwent electrophysiology study (EPS) confirming an AS-AP with anterograde and retrograde conduction. Ablation in the NCC achieved immediate and persistent anterograde conduction block. Electrophysiological maneuvers showed persistent retrograde AP conduction and orthodromic reciprocating tachycardia (ORT) remained easily inducible. Additional ablation in the NCC did not eliminate retrograde conduction. Further ablation in the RA opposite the NCC at the site of earliest retrograde atrial activation during ORT restored sinus and eliminated retrograde AP conduction. A 52-year-old male with SVT and ECG with pre-excitation underwent EPS that confirmed an AS-AP with anterograde and retrograde conduction. Ablation was performed in the NCC resulting in immediate elimination of pre-excitation. Retrograde conduction was still present and confirmed by repeating electrophysiological maneuvers. Ablation was performed in the RA opposite the successful ablation site in the NCC, eliminating retrograde AP conduction.

CONCLUSION

Two cases of AS-AP with anterograde and retrograde conduction and successful elimination of pathway conduction required a hybrid ablation approach from the NCC and RA. This approach may be helpful in other cases to improve success rates without using excessive ablation near the normal conduction system.

Etripamil Nasal Spray for Conversion of Repeated Spontaneous Episodes of Paroxysmal Supraventricular Tachycardia During Long-Term Follow-Up: Results From the NODE-302 Study

Background Self-administration of investigational intranasal L-type calcium channel blocker etripamil during paroxysmal supraventricular tachycardia (PSVT) appeared safe and well-tolerated in the phase 3 NODE-301 (Multi-Centre, Randomized, Double-Blind, Placebo-Controlled, Efficacy, and Safety Study of Etripamil Nasal Spray for the Termination of Spontaneous Episodes of Paroxysmal Supraventricular Tachycardia) trial of adults with sustained atrioventricular nodal-dependent PSVT. The NODE-302 open-label extension further characterized etripamil safety and efficacy. Methods and Results Eligible patients were monitored via self-applied cardiac monitoring system for 5 hours after etripamil self-administration. The primary end point was time-to-conversion of positively adjudicated PSVT to sinus rhythm after etripamil treatment. Probability of conversion to sinus rhythm was reported via Kaplan-Meier plot. Adverse events were based on self-reported symptoms and clinical evaluations. Among 169 patients enrolled, 105 self-administered etripamil ≥1 time for perceived PSVT (median [range], 232 [8-584] days' follow-up). Probability of conversion within 30 minutes of etripamil was 60.2% (median time to conversion, 15.5 minutes) among 188 PSVT episodes (92 patients) positively adjudicated as atrioventricular nodal dependent by independent ECG analysis. Among 40 patients who self-treated 2 episodes, 75% had a significantly consistent response by 30 minutes; 9 did not convert on either episode, and 21 converted on both episodes (χ2=8.09; P=0.0045). Forty-five of 105 patients (42.9%) had ≥1 treatment-emergent adverse event, generally transient and mild-to-moderate, including nasal congestion (14.3%), nasal discomfort (14.3%), or rhinorrhea (12.4%). No serious cardiac safety events were observed within 24 hours of etripamil. Conclusions In this extension study, investigational etripamil nasal spray was well tolerated for self-treating recurrent episodes of PSVT without medical supervision. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT03635996.

Perioperative management of a patient with haemophilia B and PSVT undergoing radiofrequency ablation: A case report

Haemophilia B is a rare inherited bleeding disorder in which patients have impaired coagulation. This study describes a patient with Haemophilia B and paroxysmal supraventricular tachycardia (PSVT) who underwent radio frequency catheter ablation (RFCA). The perioperative replacement therapy with coagulation factor IX (FIX) was agreed upon after an interdisciplinary consultation involving a team of specialists in haematology, cardiovascular medicine and cardiothoracic surgery. There were no obvious bleeding points or complications during the perioperative period following the treatment, nor recurrence of PSVT within a three-year follow-up period. In summary, RFCA can be performed safely in patients with haemophilia B on the premise of developing an individualized perioperative exogenous coagulation factor supplementation regimen based upon an adequate preoperative evaluation and clinical monitoring and management by an interdisciplinary team.

Diagnostic utility of early premature ventricular complexes in differentiating atrioventricular reentrant and atrioventricular nodal reentrant tachycardias

BACKGROUND

His-refractory premature ventricular complexes perturbing a supraventricular tachycardia (SVT) establish the presence of an accessory pathway (AP). Earlier premature ventricular complexes (ErPVCs) may perturb SVTs but are considered nondiagnostic.

OBJECTIVE

The purpose of this study was to test the hypothesis that an ErPVC will always show a difference >35 ms in its advancement of the next atrial activation during atrioventricular nodal reentrant tachycardia (AVNRT). During atrioventricular reentrant tachycardia (AVRT), a PVC delivered close to the circuit can result in greater advancement of atrial activation due to retrograde conduction via an AP. Thus, an AP response, defined as ErPVC (H1S2) advancing the subsequent atrial activation (A1-A2) more than this minimum difference (A1A2 ≤ H1S2+35 ms), establishes the presence of an AP.

METHODS

Sixty-five consecutive patients with SVT were retrospectively evaluated. ErPVCs were defined when the ventricular pacing stimulus was >35 ms ahead of the His during tachycardia.

RESULTS

Among the 65 cases, 43 were AVNRT and 22 AVRT. Fourteen AVRT cases had an AP response with a mean H1S2+35 ms of 336 ± 58 ms and A1A2 of 309 ± 51ms. No AVNRT cases had an AP response. The specificity of an AP response to ErPVC in predicting AVRT was 100%.

CONCLUSION

An AP response to PVCs (A1A2 ≤ H1S2+35 ms) is 100% specific for the presence of an AP.

Chiari network diagnosis intraoperative based on echocardiography

We report a case of a Chiari network as a possible cause of intraoperative supraventricular tachycardia with potential cardiac flow obstruction and hemodynamic collapse. The intraoperative diagnostic analysis considered detects cardiac abnormalities associated to this congenital remnant and discard common intraoperative causes of hemodynamic alterations.

A natural history of a child with monosomy 5p syndrome (Cat-cry/Cri-du-chat syndrome) during the 18 years of follow-up

A record of a natural history of a long-term case study devoted to monosomy 5p (Cat-cry/Cri-du-chat) syndrome has been described rarely. Knowledge on the range of the changes in phenotype attributable to advancing age can be useful in clinical diagnosis of monosomy 5p at the different developmental stages, including adolescence, as well in prognosis for genetic counseling. In this case a detailed analysis of the morphologic phenotype in a girl with del(5)(p13.3) observed from 4 months to 18 years of age is reported. The comparative analysis of the girl's phenotype in different developmental stages has revealed that microcephaly, flat occipital region, face asymmetry, wide spaced palpebral fissures, epicanthic folds, small mouth fissure, thin mucous lip, small and low set ears and short IV metacarpals has not changed with advancing age. However, facial asymmetry was more evident, frontal tubers were less prominent, nasal root and back became prominent nasal back became elongated, the subnasal region was shorter and marked malocclusion appeared.

Progressive Nature of Paroxysmal Atrial Fibrillation-Observations From a 14-Year Follow-up Study-

BACKGROUND

Atrial fibrillation (AF) is believed to occur first as paroxysmal, then be gradually perpetuated, and finally become chronic as the end result. However, this presumed clinical course has not been well confirmed.

METHODS AND RESULTS

The clinical course of recurrent paroxysmal AF (PAF) from its onset was examined in 171 patients (mean follow-up period: 14.1+/-8.1 years). This study population consisted of patients with no structural heart disease (n=88), ischemic heart disease (n=28), dilated or hypertrophic cardiomyopathy (n=17), valvular heart disease (n=35) or other cardiac diseases. The mean age at the onset of AF was 58.3 +/-11.8 years old. During the mean follow-up period of 14.1 years, PAF eventually developed into its chronic form in 132 patients under conventional antiarrhythmic therapy (77.2%, 5.5% of patients per year). The independent factors for early development into chronic AF were aging (hazard ratio (HR) 1.27 per 10 years, 95% confidence interval (CI) 1.06-1.47)), dilated left atrium (HR 1.39 per 10 mm, 95% CI 1.11-1.69), myocardial infarction (HR 2.33, 95% CI 1.13-4.81), and valvular diseases (HR 2.29, 95% CI 1.22-4.30).

CONCLUSIONS

The present long-term observations definitely and quantitatively revealed the progressive nature of PAF.

[A case of oligodendroglioma with temporal lobe epilepsy initially suspected as having paroxymal tachycardia]

A 4-year-old girl had repetitive attacks of chest pain, palpitation and loss of consciousness, which lasted for a few minutes and occurred several times a day. Interictal and ictal EEGs revealed that these episodes were complex partial seizures with autonomic symptoms originating from the right antero-temporal area. Brain MRI depicted a tumor in the right temporal lobe, the suspected etiology of the seizures. The tumor and its surrounding area were carefully resected using electrocorticogram. Pathologically, the tumor was diagnosed as an oligodendroglioma. MR spectrometry demonstrated a definite reduction of NAA/creatine ratio in the tumor. It is reported that a probability of developing seizures in cases of oligodendroglioma is about 80-90%. The occurrence rate of seizures in oligodendroglioma is much higher than that in other brain tumors. The cause of the epileptogenesis in oligodendroglioma might be due to the pathological tissue of satellitosis and secondary degeneration of neurons.

Neurophysiological investigations in patients with primary writing tremor

The pathophysiology of primary writing tremor (PWT) is still unknown: it has been classified as a focal form of essential tremor and as a tremulous form of writer's cramp. We studied cortical and spinal excitability in patients with PWT and compared the results with published data of patients with essential tremor, and writer's cramp. We used electrical stimulation of median and radial nerve to study reciprocal inhibition of forearm antagonist muscles and paired transcranial magnetic stimulation at short and long interstimulus intervals (ISIs) to assess intracortical excitability. Both studies were conducted on patients with PWT and on control subjects. The early (presynaptic) and late (disynaptic) phases of reciprocal inhibition were normal as was intracortical excitability at short and long ISIs. Our study suggests that the pathophysiology of PWT is different from that of writer's cramp and partially also from that of essential tremor.

Polyuria in paroxysmal tachycardia and paroxysmal atrial flutter and fibrillation

When Paul Wood spoke about this to the British Cardiac Society in 1961, we were impressed by the originality of his work on a subject that so many had noticed but failed to investigate. A few months before his death in July 1962, when I asked him if his paper was ready for the journal, he said that he had not yet been able to get all the evidence he hoped for to establish the full explanation. Unfortunately, he had not the time to complete this. I have, therefore, tried to set out as clearly as possible the stage that he had reached. Maurice Campbell

PAROXYSMAL ATRIAL TACHYCARDIA WITH BLOCK AROUND THE ECTOPIC PACEMAKER. REPORT OF A CASE

A case is presented in which an ectopic atrial pacemaker manifested "pacemaker block," a phenomenon analogous to sinoatrial block in the sinoatrial node. This is believed to be the first recorded instance of such a phenomenon.

ARRHYTHMIAS RELATED TO CARDIOVERSION

DC countershock abolished 92 of 101 episodes of atrial fibrillation in 86 patients, an incidence of 91 per cent. Supraventricular arrhythmias were not infrequent immediately after countershock. These were transient and did not complicate the procedure nor were they hazardous to the patient. On two occasions a slow atrioventricular nodal rhythm appeared followed by recurrence of atrial fibrillation a few hours later. Sinus node activity did not return in these patients. Ventricular tachycardia, fibrillation, or standstill did not occur in this series.

The following arrhythmias were observed immediately after countershock but prior to the establishment of a regular sinus rhythm: atrioventricular dissociation, 12 times; passive atrioventricular nodal rhythm, five times; atrioventricular nodal tachycardia, five times; atrial flutter or tachycardia, four times.

The conversion of fibrillation to flutter by countershock implies that the effect of the electric current was merely to shorten the length of the circulating wave, a phenomenon that can also be observed in the treatment of atrial fibrillation with quinidine.

Disorders of rhythm, probably having a different mechanism, were also observed after countershock had established a regular sinus pacemaker. In the group not treated with quinidine prior to countershock (74 episodes) atrial extrasystoles were seen 26 times (35 per cent); atrioventricular nodal extrasystoles or escapes, 18 times (24.3 per cent); atrial flutter or tachycardia, six times (8.1 per cent); atrial fibrillation, eight times (18 per cent); atrioventricular nodal tachycardias, twice (2.6 per cent); and a bizarre, multifocal atrial arrhythmia, once (1.3 per cent). The arrhythmias considered to be responsible for the recurrence of atrial fibrillation and also the possible mechanisms involved were discussed.

Pretreatment with quinidine was effective in reducing the incidence of arrhythmias occurring after conversion (27 episodes), atrial extrasystoles six times (22 per cent), atrioventricular nodal extrasystoles or escapes six times (22 per cent); atrial flutter or tachycardia three times (11 per cent); atrial fibrillation once (3.7 per cent); and atrioventricular nodal tachycardia once (3.7 per cent).