Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0018799 (heart disease)
 34,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The aim of this clinical crossover study was to elucidate the effects of atrioventricular (AV) synchronous pacing on cardiac function in patients with sick sinus syndrome (SSS). Thirty SSS patients, each with dual chamber pacemaker (DDD), were enrolled and divided into two groups based on echocardiographic findings. Group A (n = 16) had hypertensive heart disease (wall thickness 11 approximately 12 mm) or mitral or aortic regurgitation (Grade I or II). Group B (n = 14) had no organic heart disease. Three successive 3-month pacing periods were tested. For the first 3 months, long AV delay that achieved > 80% ventricular sensing was chosen. For the next 3 months, AV delay was abbreviated to achieve > 80% ventricular pacing at an optimal AV interval. For the final 3 months, the first setting was resumed. At the end of each period, M mode echocardiography, pulsed-Doppler study, and measurement of plasma brain natriuretic peptide (BNP) level were conducted. In both groups, echocardiographic parameters were not significantly changed during the evaluation. In group A, plasma BNP level was significantly higher at the end of the short AV delay period than at the long AV delay period (P = 0.009), while in group B it did not differ during each period. AV synchronous pacing (> 80% ventricular pacing) in the SSS patients with a DDD pacemaker implanted could increase the ventricular load, and it is better to preserve the spontaneous QRS with the DDD mode with prolonged AV delay in patients with mild hypertensive or valvular disease.
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PMID:Clinical significance of preserving spontaneous QRS wave in the therapy of DDD pacing for sick sinus syndrome. 1546 10

Marked first-degree AV block (PR> or =0.30 s) can produce a clinical condition similar to that of the pacemaker syndrome. Clinical evaluation often requires a treadmill stress test because patients are more likely to become symptomatic with mild or moderate exercise when the PR interval cannot adapt appropriately. Uncontrolled studies have shown that many such symptomatic patients with normal left ventricular (LV) function improve with conventional dual chamber pacing (Class IIa indication). In contrast, marked first-degree AV block with LV systolic dysfunction and heart failure is still a Class IIb indication, a recommendation that is now questionable because a conventional DDD(R) pacemaker would be committed to right ventricular pacing (and its attendant risks) virtually 100% of the time. It would seem prudent at this juncture to consider a biventricular DDD device in this situation. Patients with suboptimally programmed pacemakers may develop functional atrial undersensing because the P wave tends to migrate easily into the postventricular atrial refractory period (PVARP). Retrograde vetriculoatrial conduction block is uncommon in marked first-degree AV block so a relatively short PVARP can often be used at rest with little risk of endless loop tachycardia. The usefulness of a short PVARP may be negated by special PVARP functions in some pulse generators designed to time out a long PVARP at rest and a gradually shorter one with activity. First-degree AV block during cardiac resynchronization therapy (CRT) predisposes to loss of ventricular resynchronization during biventricular pacing because it favors the initiation of electrical "desynchronization" especially in association with a relatively fast atrial rate and a relatively slow programmed upper rate. Patients with first-degree AV block have a poorer outcome with CRT than patients with a normal PR interval, a response that may involve several mechanisms. (1) The long PR interval may be a marker of more advanced heart disease. (2) Patients with first-degree AV block may experience more episodes of undetected "electrical desynchronization". (3) "Concealed resynchronization" whereupon ventricular activation in patients with a normal PR interval may result from fusion of electrical wavefronts coming from the right bundle branch and the impulse from the LV electrode. The resultant hemodynamic response may be superior because the detrimental effects of right ventricular stimulation (required in the setting of a longer PR interval) are avoided.
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PMID:First-degree atrioventricular block. Clinical manifestations, indications for pacing, pacemaker management & consequences during cardiac resynchronization. 1733 13

The EVADEF registry enrolled 2296 patients implanted with a defibrillator between june 2001 and june 2003 and followed up 24 months. Their main characteristics were the following: their mean age was 60+/-15S years, they were male in 86 %. Their left ventricular ejection fraction was 38.9 +/- 15.9 %. They were in NYHA class I or II for 83.8% of them, in class Ill for 14.7% and in class IV for only 1.5%. Secondary prevention indications concerned 82.1%, primary prevention 18.3%. Underlying cardiopathies were coronary artery disease in 61.3%, dilated cardiomyopathies in 15.9%. In a group of 7.1% there was no underlying heart disease. The implanted devices were VVI in 48.3%, DDD in 42.9%, biventricular pacemaker with defibrillator in 8.3% and dual defibrillator in 0.5%. Periprocedure complications concerned 13.8%. The most frequently reported was the presence of an haematoma. Periprocedure mortality concerned 8 patients, i.e. 0.3% of the total cohort. Mortality was 7.2% at 1 year and 11.3% at 2 years. Among the 274 deaths, a majority was due to heart failure (42%), arrhythmic storms represented only 6.2% of deaths. Hopefully it is likely that in the future association of cardiac resynchronization therapy to defibrillator will be able to decrease this death rate due to heart failure.
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PMID:[EVADEF registry, main data]. 1747 83

Ventricular dyssynchrony induced by ventricular pacing (VP) may predispose patients to congestive heart failure. The detrimental effects of VP are directly related to the cumulative percentage of VP (Cum%VP). Managed VP (MVP) is a novel pacing algorithm developed to minimize unnecessary VP by uncoupling atrial pacing from VP. This retrospective analysis assessed the feasibility of using MVP in pediatric patients and patients with congenital heart disease (CHD). A multicenter review evaluated all pediatric patients <22 years old and older patients with CHD that had an implanted device using a MVP algorithm. Primary outcome variables were Cum%VP and adverse events. A subgroup analysis evaluated patients that had a DDD(R) pacemaker before a MVP device and compared Cum%VP before and after initiation of MVP. From 6 centers 62 patients (mean age 21.5 +/- 9.6 years) were included; 64% had CHD. With a MVP device, mean Cum%VP was 4.3 +/- 14.6% (range 0 to 83.7): Eleven patients were eligible for subgroup analysis. Compared with DDD(R), Cum%VP significantly decreased with MVP (67.1 +/- 29.4% vs 9.2 +/- 24.8%, p = 0.002). One MVP-related adverse event occurred; a patient with intermittent atrioventricular block had symptoms with frequent nonconducted atrial depolarizations and was reprogrammed to DDD. In conclusion, MVP can be used safely and can significantly reduce unnecessary VP in pediatric patients and patients with CHD.
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PMID:Managed ventricular pacing in pediatric patients and patients with congenital heart disease. 1880 14

Hypertrophic cardiomyopathy (HCM) is classified as a primary cardiomyopathy. HCM is a clinically heterogeneous but relatively common autosomal dominant genetic heart disease that probably is the most frequently occurring cardiomyopathy. HCM is characterized morphologically and defined by a hypertrophied, nondilated left ventriculum (LV) in the absence of another systemic or cardiac disease that is capable of producing the magnitude of wall thickening evident (e.g., systemic hypertension, aortic valve stenosis). Most HCM patients have the propensity to develop dynamic obstruction to LV outflow under resting or physiologically provocable conditions, produced by systolic anterior motion of the mitral valve with ventricular septal contact. The phenotypic features of HCM may develop at any age from infancy to adulthood, and are characterized by a great heterogeneity in the extent, magnitude, and distribution of left ventricular hypertrophy. Hypertrophic obstructive cardiomyopathy (HOCM) often leads to heart failure, severe ischemia, severe symptoms and death. Determination of the exact site of the hypertrophy and of the obstruction of the left ventricular outflow tract, in asymmetric septal hypertrophy, establishes which is the best treatment strategy. In the treatment of HOCM, drug therapy with negatively inotropic drugs, percutaneous transluminal septal myocardial ablation by alcohol-induced septal branch occlusion, surgical myectomy and DDD pacemaker therapy are considered the therapeutical options. We present a case of an obstructive hypertrophic cardiomyopathy in an 84-year-old Italian woman with a left ventricular outflow tract (LVOT) peak gradient with the Valsalva maneuver of 188 mm Hg and with a history of first episode of syncope.
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PMID:Revelation of an obstructive hypertrophic cardiomyopathy in an elderly patient. 1918 3

The atrial switch (Mustard, Senning procedures) was one of the treatments of choice for repair of transposition of the great arteries from the early 1960s to the mid-1980s. A significant proportion of patients with atrial switch develops systemic (right) ventricular failure. A series of surgical therapeutic options exists to manage cardiac failure in this setting, and, more recently proposed, cardiac resynchronization therapy. We describe case report of a 30-year-old woman with congenital heart disease (CHD) and previous Mustard procedure who underwent upgrading from single chamber to dual-chamber pacemaker. The narrower native QRS did not correlate with a better synchrony status nor with a better cardiac output. Functional evaluation confirmed a better performance in DDD mode with short atrioventricular delay and broad QRS. Some echocardiographic and electrocardiographic parameters, such as ejection fraction and QRS duration, well established in adults' heart for selection of candidates to cardiac resynchronization therapy, are much less studied in CHD. Postoperative CHD may provide unique patterns of asynchrony with poorly predictable hemodynamic outcome.
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PMID:Cardiac resynchronization therapy or sequential pacing in failing Mustard? 2135 69

Isolated severe tricuspid valve stenosis due to an endocardial pacemaker lead is extremely rare, and is usually caused by either fibrosis of a perforated or lacerated leaflet, or fibrotic adherence between the lead and the valvular apparatus. Reported cases typically include clinical manifestations of both systemic venous stasis and low cardiac output. The case is presented of a 20-year-old female with a surgically repaired congenital heart disease who developed severe tricuspid stenosis at six years after the implantation of a DDD pacemaker. Unexpectedly, the patient had no signs of venous stasis and suffered only from exercise intolerance. Right heart catheterization under fluoroscopic guidance revealed an atrial lead forming a loop at the level of the tricuspid valve. A paradoxical inspiratory decrease in the transvalvular diastolic gradient, caused by the caudal heart motion and straightening of the loop during inspiration, was noted. Such a dynamic nature with a temporary inspiratory relief of the obstruction may explain the partial clinical presentation of tricuspid stenosis in this case. The lead was removed and the tricuspid valve repaired surgically, after which the patient's recovery was uneventful with normalization of exercise tolerance.
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PMID:Dynamic tricuspid valve stenosis induced with a pacemaker lead: a case report. 2477 42


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