Atrial flutter ablation and risk of right coronary artery injury.

Radiofrequency ablation (RFA) of atrial flutter (AFL) is a commonly performed procedure with low risk of complications. Several case reports and animal studies cautioned about the risk of right coronary artery (RCA) injury following AFL ablation. This risk is due to the anatomic proximity of the RCA to the cavo-tricuspid isthmus where ablation is performed. We present a case report that demonstrates postmortem evidence of RCA injury following RFA of AFL.

"Head-to-toe" kissing balloon angioplasty during PCI of right coronary artery chronic total occlusion.

New techniques involving the use of retrograde channels have enabled successful revascularization of chronically occluded arteries previously not amenable to standard strategies. We describe the use of a simultaneous antegrade and retrograde approach to perform bifurcation kissing balloon angioplasty which was not possible using a standard antegrade approach. As the balloons are oriented in opposite rather than identical directions, we have named this technique "Head-to-Toe Kissing."

Utility of nuclear stress imaging for detecting coronary artery bypass graft disease.

BACKGROUND: The value of single photon emission computed tomography stress myocardial perfusion imaging (SPECT-MPI) for detecting graft disease after coronary artery bypass surgery (CABG) has not been studied prospectively in an unselected cohort. METHODS: Radial Artery Versus Saphenous Vein Graft Study is a Veterans Affairs Cooperative Study to determine graft patency rates after CABG surgery. Seventy-nine participants agreed to SPECT-MPI within 24 hours of their coronary angiogram, one-year after CABG. The choice of the stress protocol was made at the discretion of the nuclear radiologist and was either a symptom-limited exercise test (n = 68) or an adenosine infusion (n = 11). The SPECT-MPI results were interpreted independent of the angiographic results and estimates of sensitivity, specificity and accuracy were based on the prediction of a graft stenosis of ≥70% on coronary angiogram. RESULTS: A significant stenosis was present in 38 (48%) of 79 patients and 56 (22%) of 251 grafts. In those stress tests with an optimal exercise heart rate response (>80% maximum predicted heart rate) (n = 26) sensitivity, specificity and accuracy of SPECT-MPI for predicting the graft stenosis was 77%, 69% and 73% respectively. With adenosine (n = 11) it was 75%, 57% and 64%, respectively. Among participants with a suboptimal exercise heart rate response, the sensitivity of SPECT-MPI for predicting a graft stenosis was <50%. The accuracy of SPECT-MPI for detecting graft disease did not vary significantly with ischemic territory. CONCLUSIONS: Under optimal stress conditions, SPECT-MPI has a good sensitivity and accuracy for detecting graft disease in an unselected patient population 1 year post-CABG.

Proximity of right coronary artery to cavotricuspid isthmus as determined by computed tomography.

BACKGROUND: Radiofrequency ablation of atrial flutter is a commonly performed procedure. Ablation success depends upon complete transmural atrial tissue injury to achieve bidirectional cavotricuspid isthmus (CTI) block. Transmural ablation increases risk of injury to the adjacent right coronary artery (RCA). Distance between the RCA and the endocardium within the CTI area is not well described. We aimed to perform in vivo measurements of the distance between the CTI area and adjacent RCA. METHODS: Thirty-three consecutive patients underwent electrocardiogram-gated contrast-enhanced computed tomography. CTI area was divided into nine segments based on three common catheter locations (paraseptal, central, and lateral or 5, 6, and 7 o'clock) and ventricular to atrial ablation line. RESULTS: Mean age was 64 ± 11 years and 97% of the participants were male. Paraseptal, central, and lateral measurements at the tricuspid annulus ridge showed endocardial to RCA distance 9 ± 3, 6 ± 2, and 5 ± 3 mm, respectively (range 2-17 mm). Corresponding measurements for the ventricular side were 5 ± 3, 4 ± 2, and 4 ± 2 mm and atrial side measurements were 3 ± 2, 3 ± 2, and 3 ± 3 mm. Distance was ≤2 mm in 14% of segments on the ventricular side and 39% of segments on the atrial side. Paired t-test showed significant difference (P < 0.001) between tricuspid annulus ridge measurements and adjacent atrial or ventricular measurements. CONCLUSIONS: Distance between endocardium and RCA lumen is reduced in areas adjacent to the tricuspid annulus ridge.

Electrocardiographic markers of cardioversion success in patients with atrial fibrillation.

BACKGROUND: In patients with atrial fibrillation (AF) and atrial flutter (AFL), the value of the 12-lead surface electrocardiogram (ECG) in predicting direct current cardioversion (DCCV) outcomes has not been thoroughly investigated. We sought to determine whether the type of atrial arrhythmia (AF versus AFL) and the characteristics of the atrial fibrillatory waves (fine versus coarse) on the surface ECG would help predict post DCCV outcomes. METHODS: A total of 76 consecutive patients undergoing elective DCCV for persistent AF or AFL at the Minneapolis Veterans Affairs Medical Center were included in this retrospective cohort study. All patients had ECGs immediately and one month after DCCV. RESULTS: Mean age was 67+/-8 years and 97% of the participants were male. DCCV was immediately successful in 64 (84%) patients. Of these, 35 (46%) remained in sinus rhythm at one month. DCCV was immediately successful in all patients (N 13) with fine AF versus 34/45 of those with coarse AF (P 0.05). Patients with fine AF were also more likely to remain in sinus rhythm at one-month follow up compared to those with coarse AF (8/13 versus 13/45; P 0.03). Also, at one-month follow up, the patients with AFL were more likely to maintain sinus rhythm than those with AF (14/18 of AFL versus 21/58 of AF; P 0.003). CONCLUSION: The characteristics of the fibrillatory waves on surface ECG should be utilized to determine the success after DCCV in patients with AF and AFL.

Efficacy of gemfibrozil in the primary prevention of atrial fibrillation in a large randomized controlled trial.

BACKGROUND: Peroxisome proliferator-activated receptor alpha (PPARalpha) activators reduce inflammation and oxidative stress. Inflammation plays an important role in the initiation and maintenance of atrial fibrillation (AF). It has been suggested that PPARalpha activators may have antiarrhythmic properties, but no clinical data exist. The objective of this study was to investigate whether the PPARalpha activator gemfibrozil prevents or delays the development of AF in patients with coronary heart disease. METHODS: We retrospectively analyzed the electrocardiograms (ECGs) performed in the Veterans Affairs High-Density Lipoprotein Cholesterol Intervention Trial, a multicenter, randomized, double-blinded, secondary prevention trial of gemfibrozil and matching placebo. The ECGs were performed annually or biannually and when clinically indicated. Participants who were in AF on baseline ECG were excluded from the present analysis. Relative risk for AF was calculated from Cox regression with death as a competing risk factor. RESULTS: A total of 12,605 ECGs from 2,130 participants were interpreted (5.9 +/- 2.1 ECGs per participant, range 2-20). At baseline, the gemfibrozil (n = 1,070) and placebo (n = 1,060) groups were well matched. Mean age was 64.1 +/- 7.1 years. Over 4.4 +/- 1.5 years of follow-up, 123 (5.8%) participants developed new AF. There was no difference in AF incidence between the gemfibrozil and placebo groups (64/1,070 vs 59/1,060, respectively; P = .33). In Cox regression, the risk of AF was similar between the 2 study groups (hazard ratio 1.04, 95% CI 0.73-1.49, P = .82). CONCLUSIONS: In this post hoc analysis of a multicenter, double-blinded, randomized controlled trial, the PPARalpha activator gemfibrozil did not reduce the 4-year incidence of AF among men with coronary heart disease.

Arrhythmias associated with electroconvulsive therapy in hypertrophic cardiomyopathy.

Patients with hypertrophic cardiomyopathy (HCM) are inherently prone to arrhythmias. Electroconvulsive therapy (ECT), a well-known treatment in psychiatry, leads to a catecholamine surge and may cause arrhythmias in patients with severe coronary and valvular heart diseases and heart failure. Whether ECT is safe in HCM is unknown. We systematically investigated the effects of ECT on the arrhythmia profile and left ventricular outflow obstruction of a HCM patient by serial ambulatory Holter electrocardiograms and echocardiograms before and after ECT. Our observations provide insight into the evaluation and management of a HCM patient undergoing ECT.

Medical residents' self-reported adherence to guidelines during placement of central venous catheters .

In teaching hospitals, the majority of central venous catheters are placed by medical residents. No studies have examined residents' adherence to safe practices during these procedures. We conducted a survey to gather self-reported data on the techniques that internal medicine residents use when placing a central venous catheter to minimize their own risk of infection and their patients' risk of bleeding-related complications.

Brugada pattern electrocardiogram associated with supratherapeutic phenytoin levels and the risk of sudden death.

The emergence of Brugada pattern on electrocardiogram in response to class IA or IC antiarrhythmic agents is widely utilized to diagnose concealed Brugada syndrome and recognized as a risk factor for sudden death. Phenytoin, a class IB antiarrhythmic agent, has not been reported to induce Brugada pattern. We report a patient who presented with Brugada electrocardiogram at supratherapeutic phenytoin level. Considering that patients with syncope may falsely be labeled to have seizures and some epilepsy patients are at increased risk of sudden death, all patients with supratherapeutic phenytoin level should be evaluated with an electrocardiogram for emergence of Brugada pattern.

Atrial fibrillation associated with hypokalemia due to primary hyperaldosteronism (Conn's syndrome).

Aldosterone is a major regulator of the body potassium stores through its role in potassium excretion by the kidney. However, it is unclear whether aldosterone affects transcellular distribution of potassium in atrial myocytes, and whether hypokalemia associated with primary hyperaldosteronism increases susceptibility to atrial fibrillation (AF). We report a case of a 58-year-old male with Conn's syndrome in whom symptomatic AF was related to hypokalemia.