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Third-degree block [keywords]
- Effects of Different Ventricular Pacing Modes on Ventricular Repolarisation in Patients Undergoing Cardiac Resynchronisation Therapy: A single-centre study. [JOURNAL ARTICLE]
- Heart Lung Circ 2014 Feb 22.
The aims of this study were to compare ventricular repolarisation parameters in patients who underwent cardiac resynchronisation therapy (CRT) at Sun Yat-sen University Memorial Hospital under different ventricular pacing modes and to understand effects of epicardial pacing on ventricular repolarisation.The study included 55 patients who underwent CRT. During follow-up outpatient visits three months after CRT implantation, the CRT devices were programmed to deliver no pacing (with the exception of patients with third-degree atrioventricular block), biventricular pacing (BivP), right ventricular endocardial pacing (RV-EndoP), and left ventricular epicardial pacing (LV-EpiP). Signals from the standard 12-lead ECG were recorded simultaneously to measure the QT interval, JT interval, and Tp-e interval, from which the heart rate-corrected QTc interval, JTc interval, and Tp-ec interval were determined.The JTc interval and Tp-ec interval were prolonged during LV-EpiP and BivP compared with those during spontaneous cardiac rhythm and RV-EndoP. The JTc dispersion and Tp-ec dispersion were not significantly different among the four pacing modes.Epicardial pacing prolongs myocardial repolarisation time and increases transmural dispersion of repolarisation. Epicardial pacing has no significant effect on the dispersion of regional ventricular repolarisation.
- Reduction of unnecessary right ventricular pacing by managed ventricular pacing and search AV+ algorithms in pacemaker patients: 12-month follow-up results of a randomized study. [JOURNAL ARTICLE]
- Europace 2014 Apr 4.
The present study was to assess the reduction of right ventricular pacing (RVP) by pacemaker algorithms of Managed Ventricular Pacing (MVP) and Search AV+ (SAV+) interval over a period of 12 months.METHODS AND RESULTS: A total of 385 patients indicated for a dual-chamber pacemaker (DC-PM) were enrolled in the prospective, randomized COMPARE study at 29 centres in China between June 2009 and April 2011. Patients implanted with DC-PMs were randomized in a 1 : 1 ratio to the MVP group or the SAV+ group. The percentage of VP (%VP) was obtained from the device diagnostic data at 1-, 6-, and 12-month follow-ups and was expressed as the median %VP over all beats in patients with sinus node dysfunction (SND) and atrioventricular block (AVB) excluding persistent third-degree AVB.Of 385 enrolled patients, 253 had SND and 72 had AVB. The %VP in the MVP group was significantly lower than that in the SAV+ group at 1-, 6-, and 12-month follow-ups, respectively. At 12-month follow-up, the median %VP in SND patients was 0.20% in the MVP group and 1.4% in the SAV+ group (P < 0.0001) and the median %VP in AVB patients was 11.8% in the MVP group and 98.1% in the SAV+ group (P < 0.001). There was no statistical difference in %VP from 1- to 12-month follow-up. A trend in the correlation between %VP and AT/AF burden was observed.CONCLUSION: Over 12-month follow-up, the %VP was lower for MVP than SAV+ in patients with either SND or AVB. The sustainable %VP reduction has potential implications in reducing the development of heart failure and/or atrial arrhythmia morbidity.
- Common questions about pacemakers. [Journal Article]
- Am Fam Physician 2014 Feb 15; 89(4):279-82.
Pacemakers are indicated in patients with certain symptomatic bradyarrhythmias caused by sinus node dysfunction, and in those with frequent, prolonged sinus pauses. Patients with third-degree or complete atrioventricular (AV) block benefit from pacemaker placement, as do those with type II second-degree AV block because of the risk of progression to complete AV block. The use of pacemakers in patients with type I second-degree AV block is controversial. Patients with first-degree AV block generally should not receive a pacemaker except when the PR interval is significantly prolonged and the patient is symptomatic. Although some guidelines recommend pacemaker implantation for patients with hypersensitive carotid sinus syndrome, recent evidence has not shown benefit. Some older patients with severe neurocardiogenic syncope may benefit from pacemakers, but most patients with this disorder do not. Cardiac resynchronization therapy improves mortality rates and some other disease-specific measures in patients who have a QRS duration of 150 milliseconds or greater and New York Heart Association class III or IV heart failure. Patients with class II heart failure and a QRS of 150 milliseconds or greater also appear to benefit, but there is insufficient evidence to support the use of cardiac resynchronization therapy in patients with class I heart failure. Cardiac resynchronization therapy in patients with a QRS of 120 to 150 milliseconds does not reduce rates of hospitalization or death.
- When Should We Consider the Diagnosis of Giant Cell Myocarditis? Revisiting "Classic" Echocardiographic and Clinical Features of This Rare Pathology. [JOURNAL ARTICLE]
- Exp Clin Transplant 2014 Mar 19.
Giant cell myocarditis is a rare and often fatal disorder. According to the American Heart Association, the American College of Cardiology Foundation, and the European Society of Cardiology scientific statements, an endomyocardial biopsy should be done to exclude giant cell myocarditis in unexplained new-onset heart failure of 2 weeks to 3 months duration associated with dilated left ventricle and new ventricular arrhythmias, or Mobitz type II second-degree, or third-degree atrioventricular heart block.Two hundred thirty-five heart transplants were performed since May 1993 at the Institut universitaire de cardiologie et de pneumologie de Quebec, Canada. Giant cell myocarditis was found in the explanted hearts of 5 patients. The preoperative diagnosis of giant cell myocarditis was done by endomyocardial biopsy or at the installation of a left ventricular-assisted device. Patients had symptoms of progressive heart failure of subacute onset. Patients consulted at a mean 32 days after the onset of symptoms. Two patients neither had ventricular arrhythmia nor heart block. Two patients had ventricular arrhythmias and heart block; the other patient had symptomatic heart block. All patients had at least 2 echocardiographies. Two patients had an increase in left ventricular size, enough to reach the criteria of left ventricular dilatation according to the American Society of Echocardiography. During this time, left ventricular ejection fraction showed a rapid decline (mean 37% to 16%).Ventricular arrhythmia, heart block, and left ventricular dilatation initially can be absent in many patients having giant cell myocarditis with symptoms of progressive heart failure. Endomyocardial biopsy should be quickly considered in patients with a rapid and dramatic decline of left ventricular ejection fraction, even in the absence of classic clinical and echocardiographic features of giant cell myocarditis to rapidly obtain the diagnosis of this rare but lethal disease.
- Antenatal diagnosis of left atrial isomerism and heterotaxy syndrome in fetus with Meckel-Gruber syndrome. [Journal Article]
- Turk Kardiyol Dern Ars 2014 Mar; 42(2):182-5.
We aimed to present a fetus with Meckel-Gruber syndrome (MKS) who had left atrial isomerism, heterotaxy syndrome and complete heart block. A 26-year-old healthy female was referred to our clinic in the 23rd week of her pregnancy. The fetus had multiple systemic anomalies including fetal heart. Fetal echocardiography revealed a horizontal liver, left-sided stomach and vena cava interruption with azygos continuation. There was also an apical trabecular ventricular septal defect, aorta and pulmonary artery arising from the left ventricle, pulmonary artery hypoplasia, pulmonary valve stenosis and left atrial isomerism. The heart rate was 46/min, consistent with third-degree atrioventricular block. Multiple anomalies including occipital encephalocele, bilateral polycystic kidneys, cleft lip, cleft palate, and polydactyly were also detected in the obstetric ultrasonography. The pregnancy was terminated in the 23rd gestational week based on the consensus of perinatology council. The autopsy examination confirmed the diagnosis of MKS, left atrial isomerism and heterotaxy syndrome. Although some cardiac defects have been reported previously in MKS fetuses, here we expand the cardiac spectrum of anomalies associated with MKS to include left atrial isomerism and heterotaxy syndrome.
- Prognostic implications of atrio-ventricular block in patients undergoing primary coronary angioplasty in the stent era. [Journal Article]
- Acute Card Care 2014 Mar; 16(1):1-8.
Conduction disorders in patients with ST-segment elevation myocardial infarction (STEMI) are associated with high mortality. Previous studies have analyzed the implications of AVB in acute coronary syndrome treated with fibrinolysis. However, the implications of AVB in patients with STEMI treated with primary angioplasty have not been sufficiently studied.913 patients with STEMI treated with primary angioplasty. All clinical, electrocardiographic and angiographic variables were collected.AVB was documented in 115 patients (12.6%). On admission, AVB was present in 70 (7.7%), and persistent at hospital discharge in 36 (3.9 %). Within these, first-degree AVB was present in 29 (3.2%), second-degree in 27 (3%) and third-degree in 73 (8%). AVB was more frequent in women, elderly, hypertensive, diabetic, with worse functional class (Killip class > 2) and with higher incidence at inferior infarctions (P < 0.05). AVB in general and, more specifically, third-degree AVB was associated with a higher mortality (20.5% versus 5.7%; P < 0.001), re-infarction (8.2% versus 3.6%; P = 0.06) and a greater incidence of cardiogenic shock (33.3% versus 14%; P < 0.001). Interestingly, these events were more common in patients who had persistent AVB at hospital discharge than in those with transitory AVB or present at admission AVB. In the multivariate analysis, persistent AVB at hospital discharge proved to be an independent predictor of cardiovascular events (death and recurrent infarction), not the rest of AVB.AVB in patients who underwent primary angioplasty is associated with a worse prognosis while is in-hospital. This risk is particularly high in patients who had persistent AVB at hospital discharge.
- [Interatrial block as anatomical-electrical substrate for supraventricular arrhythmias: Bayeś syndrome]. [English Abstract, Journal Article]
- Arch Cardiol Mex 2014 Jan-Mar; 84(1):32-40.
In this article we aimed to establish that interatrial block exists as an anatomical-electrical entity, which should be considered a true block. Interatrial block presents with different degrees as other blocks in the conduction system. It shows a correlation with the left atrium size, however, it can be seen in patients with normal atrial size too. Interatrial block is strongly associated with atrial arrhythmias and it could be considered a predictor of cardioembolic stroke. Interatrial block is an expression of atrial electrical remodeling and dysfunction. IAB can be transient and in certain clinical circumstances, may be reversible. The contribution of endocardial mapping has increased our knowledge of the anatomy and pathophysiology of interatrial block. Magnetocardiography could be a possible non-invasive procedure to further investigate this entity. The interatrial block classification should include first, second and third degree or alternatively, in order to simplify the terminology: partial or advanced. The P wave morphology should always be taking into consideration when diagnosing this condition. Finally, without the initial description of interatrial block made by Dr. Bayés de Luna, it would be impossible to understand interatrial block as an anatomical and electrical substrate for atrial arrhythmias. It is our opinion that this represents a major contribution to the knowledge of electrocardiography and electrophysiology, and makes commendable that this arrhythmic syndrome should be called «Bayés' syndrome»
- Automated functıonal ımagıng ın atrıoventrıcular delay tıme optımızatıon ın patıents wıth dual chamber pacemakers. [JOURNAL ARTICLE]
- Kardiol Pol 2014 Mar 27.
Optimization of atrioventricular (AV) delay time has positive effects on left ventricular functions in patients with DDD pacemaker. However, the method used for optimization is still debated. In our study, we aimed to evaluate the effect of different AV delay times on variation of left ventricular systolic performance by using automated functional imaging (AFI) in patients with DDD pacemaker and preserved left ventricular systolic function.The study population consisted of 40 patients with DDD pacemaker implanted for third degree AV block and preserved left ventricular systolic function (19 men; mean age 64,3 ± 10,9 years). During each pacing period, blood samples were taken for measurement of brain natriuretic peptide (BNP) levels, telemetric and echocardiographic evaluations were performed to all patients. Also peak systolic global longitudinal strain (PSGLS) was calculated by using AFI method.No significant differences except for left ventricular outflow tract-velocity time integral (LVOT-VTI) were observed in pulse wave Doppler parameters with different AV delay times. PSGLS were better at 150 and 200 ms AV delay times when compared to 100 ms (p<0,001 for 100-150 ms and 100-200 ms). Similarly LVOT-VTI values were significantly higher at 150 and 200 ms AV delay times when compared to 100 ms (for 100-150 ms p=0,017 and for 100-200 ms p=0,013). Also there was a significant reduction in BNP levels at 150 ms and 200 ms compared with 100 ms AV delay time (for 100-150 ms p=0,001, and for 100-200 ms p<0,001).In patients with implanted DDD pacemaker and preserved left ventricular systolic function, increasing AV delay time has beneficial effects on left ventricular systolic performance in acute phase, as shown by AFI method in our study.
- Complete atrioventricular septal defect: comparison of modified single-patch technique with two-patch technique in infants. [Journal Article]
- J Card Surg 2014 Mar; 29(2):251-5.
The purpose of this study was to compare the modified single-patch technique with the two-patch technique for infants with complete atrioventricular septal defects (AVSDs).Between December 2001 and October 2011, 98 infants underwent complete AVSD primary repair. Forty-six patients had a modified single-patch technique; 59 patients had a two-patch technique. Eighty-seven patients had follow-up by echocardiography to measure the degree of valve regurgitation.There were two deaths (one in modified single-patch group and one in two-patch group). Cross-clamp times and cardiopulmonary bypass times were shorter in the modified single-patch group (70.56 ± 21.05 vs. 83.76 ± 22.74 minutes, p=0.004; 95.02 ± 19.73 vs. 109.9 ± 34.07, p=0.011). There was no patient with third-degree atrioventricular (AV) block in the modified single-patch group, while two patients in the two-patch group required a pacemaker (3.85%, p=NS). During follow-up, one death occurred in the single-patch group and three deaths in the two-patch group. At last follow-up, ten patients had more than moderate left AV valve regurgitation (four in single-patch group vs. six in two-patch group, p=0.886) and eight patients required reoperation (three in single-patch group vs. five in two-patch group, p=0.841). One patient in the single-patch group required reoperation for a residual ventricular septal defect and none in the two-patch group.Modified single-patch repair in infants with complete AVSD is a safe and reproducible technique. The results are as good as the two-patch technique. Among long-term survivors, most have very good clinical and functional results and minimal or no regurgitation of either AV valve.
- Reevaluation of the indications for permanent pacemaker implantation after transcatheter aortic valve implantation. [Journal Article]
- J Invasive Cardiol 2014 Feb; 26(2):94-9.
Conduction abnormalities (CA) requiring permanent pacemaker (PPM) are a well-known complication after transcatheter aortic valve implantation (TAVI). This study aimed to determine the incidence of TAVI-related PPM and reevaluate the indications for PPM after the periprocedural period.A total of 258 consecutive patients underwent TAVI with the Medtronic CoreValve (MCV), whereas 24 patients were excluded from the study. TAVI-related PPM was defined as PPM implantation ≤30 days after the procedure and due to atrioventricular block (AVB). Third-degree AVB, second-degree type-II, or advanced second-degree AVB were considered as absolute indications for PPM. The incidence of TAVI-related PPM implantation was 27.4%. Forty-six patients (19.7%) had an absolute indication for PPM, but CA had resolved in 50% beyond the periprocedural period. Electrocardiographic analysis of the patients who did not have a TAVI-related PPM implantation showed that the PR and QRS intervals increased following TAVI, reaching a peak on days 4-6 and 7-9, respectively, before decreasing to near baseline levels.Although the incidence of periprocedural PPM implantation following TAVI was high, most CAs following TAVI tend to resolve after the periprocedural period. This suggests that delaying the decision for PPM implantation after TAVI may reduce the PPM rate.