In 490 cases of sudden cardiac death identified over a 3-year period (annual incidence of 1.3 per 100,000), causes were found in 60% through conventional autopsy, and a clinically relevant cardiac ...gene mutation was found in 27% of the remaining cases in which genetic testing was performed.
Sudden cardiac death among children and young adults is a devastating event for the family and wider community. Coronary artery disease is the predominant cause of sudden cardiac death in older persons,
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whereas among persons 1 to 35 years of age, sudden cardiac death is more often caused by structural heart disease, including hypertrophic cardiomyopathy, dilated cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, myocarditis, and primary arrhythmogenic disorders (such as the congenital long-QT syndrome, the Brugada syndrome, and catecholaminergic polymorphic ventricular tachycardia).
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Many of these cardiac causes of sudden cardiac death among children and young adults have an underlying genetic basis. . . .
Mitral valve prolapse (MVP) is commonly observed as a benign finding. However, the literature suggests that it may be associated with sudden cardiac death (SCD). We performed a meta-analysis and ...systematic review to determine the: (1) prevalence of MVP in the general population; (2) prevalence of MVP in all SCD and unexplained SCD; (3) incidence of SCD in MVP and (4) risk factors for SCD.
The English medical literature was searched for: (1) MVP community prevalence; (2) MVP prevalence in SCD cohorts; (3) incidence SCD in MVP and (4) SCD risk factors in MVP. Thirty-four studies were identified for inclusion. This study was registered with PROSPERO (CRD42018089502).
The prevalence of MVP was 1.2% (95% CI 0.5 to 2.0) in community populations. Among SCD victims, the cause of death remained undetermined in 22.1% (95% CI 13.4 to 30.7); of these, MVP was observed in 11.7% (95% CI 5.8 to 19.1). The incidence of SCD in the MVP population was 0.14% (95% CI 0.1 to 0.3) per year. Potential risk factors for SCD include bileaflet prolapse, ventricular fibrosis complex ventricular ectopy and ST-T wave abnormalities.
The high prevalence of MVP in cohorts of unexplained SCD despite low population prevalence provides indirect evidence of an association of MVP with SCD. The absolute number of people exposed to the risk of SCD is significant, although the incidence of life-threatening arrhythmic events in the general MVP population remains low. High-risk features include bileaflet prolapse, ventricular fibrosis, ST-T wave abnormalities and frequent complex ventricular ectopy.
PROSPERO (CRD42018089502).
Chronic kidney disease (CKD) patients undergoing hemodialysis (HD) have a high risk of sudden cardiac death (SCD). A unique risk factor may be a longer interval between HD sessions (interdialytic ...period). Inherent in conventional HD (thrice-weekly) are two 48-hour short breaks (SIDP) and one 72-hour long break (LIDP) between HD sessions.
We used an implantable cardiac monitor (ICM) to define the incidence and timing of significant arrhythmias in an HD population.
Fifty CKD patients undergoing HD with left ventricular ejection fraction >35% had an ICM inserted, with intensive follow-up to record SCD events and predefined bradyarrhythmias and tachyarrhythmias.
Mean age of the patients was 67 ± 11 years; 72% were male, and the mean follow-up was 18 ± 4 months. There were 8 unexpected SCDs (16%), all during the LIDP. The terminal event was severe bradycardia with asystole in each recorded case. No episodes of polymorphic ventricular tachycardia (VT) occurred. A total of 7686 arrhythmia events were recorded in 43 patients (86%), including bradycardia in 15 patients (30%), sinus arrest in 14 (28%), second-degree atrioventricular block in 4 (8%), nonsustained VT in 10 (20%), and new-onset paroxysmal atrial fibrillation in 14 (28%). The LIDP was the highest-risk period for all arrhythmias (P < .001). The arrhythmia event rate per hour was greatest during the first pre-HD period of the week compared with any other peri-HD period (P < .001).
Risk of SCD and significant arrhythmias is greatest during the LIDP. SCD was attributable to severe bradycardia and asystole. Interventions to prevent this type of SCD or shorten the LIDP deserve further evaluation.
URL: https://www.anzctr.org.au (Unique identifier: ACTRN12613001326785).
The purpose of this study was to perform a detailed analysis of the P-wave morphology (PWM) in focal atrial tachycardia (AT) and construct and prospectively evaluate an algorithm for identification ...of the anatomic site of origin.
Although smaller studies have described the PWM from particular anatomic locations, a detailed algorithm characterizing the likely location of a tachycardia associated with a P-wave of unknown origin has been lacking.
The PWMs for 126 consecutive patients undergoing successful radiofrequency ablation of 130 ATs are reported. P waves were included only when the onset was preceded by a discernible isoelectric segment. P waves were classified as positive (+), negative (-), isoelectric, or biphasic. Sensitivity, specificity, and predictive values were calculated. On the basis of these results, an algorithm was constructed and prospectively evaluated in 30 new consecutive ATs.
The distribution of ATs was right atrial (RA) in 82 of 130 (63%) and left atrial (LA) in 48 of 130 (37%). Right atrial sites included crista (n = 28), tricuspid annulus (n = 29), coronary sinus (CS) ostium (n = 14), perinodal (n = 7), right septum (n = 1), and RA appendage (n= 3). Left atrial sites included pulmonary veins (n = 32), mitral annulus (n = 8), CS body (n= 3), left septum (n = 3), and LA appendage (n = 2). In electrocardiographic lead V1, a negative or +/- P-wave demonstrated a specificity of 100% for a RA focus, and a + or -/+ P-wave demonstrated a sensitivity of 100% for a LA focus. A characteristic PWM was associated with high sensitivity and specificity at common atrial sites for tachycardia foci. A P-wave algorithm correctly identified the focus in 93%.
Characteristic PWMs corresponding to known anatomic sites for focal AT are associated with high specificity and sensitivity. A P-wave algorithm correctly identified the site of tachycardia origin in 93%.
Abstract Background Mutations in LMNA are variably expressed and may cause cardiomyopathy, atrioventricular block (AVB), or atrial arrhythmias (AAs) and ventricular arrhythmias (VA). Detailed natural ...history studies of LMNA -associated arrhythmic and nonarrhythmic outcomes are limited, and the prognostic significance of the index cardiac phenotype remains uncertain. Objectives This study sought to describe the arrhythmic and nonarrhythmic outcomes of LMNA mutation carriers and to assess the prognostic significance of the index cardiac phenotype. Methods The incidence of AVB, AA, sustained VA, left ventricular systolic dysfunction (LVD) (= left ventricular ejection fraction ≤50%), and end-stage heart failure (HF) was retrospectively determined in 122 consecutive LMNA mutation carriers followed at 5 referral centers for a median of 7 years from first clinical contact. Predictors of VA and end-stage HF or death were determined. Results The prevalence of clinical manifestations increased broadly from index evaluation to median follow-up: AVB, 46% to 57%; AA, 39% to 63%; VA, 16% to 34%; and LVD, 44% to 57%. Implantable cardioverter-defibrillators were placed in 59% of patients for new LVD or AVB. End-stage HF developed in 19% of patients, and 13% died. In patients without LVD at presentation, 24% developed new LVD, and 7% developed end-stage HF. Male sex (p = 0.01), nonmissense mutations (p = 0.03), and LVD at index evaluation (p = 0.004) were associated with development of VA, whereas LVD was associated with end-stage HF or death (p < 0.001). Mode of presentation (with isolated or combination of clinical features) did not predict sustained VA or end-stage HF or death. Conclusions LMNA -related heart disease was associated with a high incidence of phenotypic progression and adverse arrhythmic and nonarrhythmic events over long-term follow-up. The index cardiac phenotype did not predict adverse events. Genetic diagnosis and subsequent follow-up, including anticipatory planning for therapies to prevent sudden death and manage HF, is warranted.
Patients with chronic kidney disease (CKD) undergoing hemodialysis experience a high annual mortality rate (7% per year) with 25% of all deaths due to sudden cardiac death (SCD) (1). Exclusion ...criteria included severe LV dysfunction (LV ejection fraction <35%), New York Heart Association class IV symptoms, pre-existing pacemaker or implantable cardioverter-defibrillator in situ, and a previous history of clinical ventricular tachyarrhythmias or syncope.
It has been reported that cardiological screening and genetic evaluation in relatives of families with sudden unexplained death syndrome and unexplained cardiac arrest (UCA) may uncover a heritable ...etiology in a significant proportion of families.
To evaluate the yield of a comprehensive evaluation protocol of a large unselected cohort of consecutive families with autopsy-negative sudden unexplained death syndrome (termed sudden arrhythmic death syndrome SADS) and UCA.
We studied (1) 109 consecutive families (411 relatives) referred with 1 or more sudden deaths in the family and (2) 52 consecutive probands with UCA (91 relatives) referred by cardiologists between January 2007 and December 2012. A comprehensive cardiological screening was performed followed by targeted genetic evaluation if a clinical phenotype was proven or suspected. Diagnosis was made by a multidisciplinary team using published clinical criteria.
A diagnosis was made in 19 of 109 families with SADS (yield 18%), with the majority having long QT syndrome (LQTS). Diagnosis varied according to proband age, with LQTS most common in the very young (≤20 years) and Brugada syndrome in the older age probands (≥40 years) (P = .03). In contrast, a diagnosis was made in 32 of 52 families with UCA (yield 62%), the majority of which had LQTS and Brugada syndrome. No clinical or circumstantial factors increased the likelihood of diagnosis in families with either SADS or UCA.
In contrast to previously published series, a comprehensive strategy of cardiological evaluation and targeted genetic testing in more than 100 families with SADS was found to have a lower diagnostic yield (18%). Diagnostic yield in families with UCA was approximately 4 times higher (62%), which is consistent with the published literature.
This study aimed to characterize the incidence, clinical and electrophysiologic features, and long-term outcomes of patients with tachycardia-mediated cardiomyopathy (TCM) secondary to focal atrial ...tachycardia (AT).
TCM is known to complicate atrial tachyarrhythmias. Little is known of the patient and tachycardia characteristics associated with the development of left ventricular (LV) dysfunction and the long-term outcomes after cure of tachycardia.
A total of 345 patients with focal AT underwent radiofrequency ablation between January 1997 and July 2008. A retrospective analysis was performed to identify patients with LV dysfunction, defined as an ejection fraction <50% on echocardiography. Patients with pre-existing structural heart disease (n = 14) were excluded. Patients with TCM (n = 30) and without TCM (n = 301) were compared. Recovery of LV function was also assessed.
The incidence of TCM was 10%. Incessant or very frequent paroxysmal tachycardia was strongly associated with TCM, compared to patients without TCM (100% vs. 20%, p < 0.001). Patients in the TCM group were younger (mean age 39 +/- 22 years vs. 51 +/- 17 years, p = 0.0006) and more frequently male (60% vs. 38%, p < 0.001). Patients with TCM had a longer mean tachycardia cycle length (502 +/- 131 ms vs. 402 +/- 105 ms, p < 0.0001) and slower ventricular rate (117 +/- 21 beats/min vs. 141 +/- 33 beats/min, p = 0.0007) during tachycardia compared with patients who did not have TCM. Appendage sites are associated with a high incidence of incessant tachycardia (84%) and LV dysfunction (42%). After successful ablation, LV function was restored in 97% of patients at a mean of 3 months.
Cardiomyopathy occurs in 10% of patients with focal AT. A slower incessant tachycardia is more frequently complicated by cardiomyopathy. Long-term restoration of LV function can be achieved after successful catheter ablation of the tachycardia focus.
Background The association between mitral valve prolapse (MVP) and sudden death remains controversial. We aimed to describe histopathological changes in individuals with autopsy-determined isolated ...MVP (iMVP) and sudden death and document cardiac arrest rhythm. Methods and Results The Australian National Coronial Information System database was used to identify cases of iMVP between 2000 and 2018. Histopathological changes in iMVP and sudden death were compared with 2 control cohorts matched for age, sex, height, and weight (1 group with noncardiac death and 1 group with cardiac death). Data linkage with ambulance services provided cardiac arrest rhythm for iMVP cases. From 77 221 cardiovascular deaths in the National Coronial Information System database, there were 376 cases with MVP. Individual case review yielded 71 cases of iMVP. Mean age was 49±18 years, and 51% were women. Individuals with iMVP had higher cardiac mass (447 g versus 355 g;
<0.001) compared with noncardiac death, but similar cardiac mass (447 g versus 438 g;
=0.64) compared with cardiac death. Individuals with iMVP had larger mitral valve annulus compared with noncardiac death (121 versus 108 mm;
<0.001) and cardiac death (121 versus 110 mm;
=0.002), and more left ventricular fibrosis (79% versus 38%;
<0.001) compared with noncardiac death controls. In those with iMVP and witnessed cardiac arrest, 94% had ventricular fibrillation. Conclusions Individuals with iMVP and sudden death have increased cardiac mass, mitral annulus size, and left ventricular fibrosis compared with a matched cohort, with cardiac arrest caused by ventricular fibrillation. The histopathological changes in iMVP may provide the substrate necessary for development of malignant ventricular arrhythmias.
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