About
Zaid Aziz, MD, is an Assistant Professor of Medicine in the Department of Medicine at The University of Chicago. His clinical interests include arrhythmias, atrial fibrillation, catheter ablation of cardiac arrhythmias, heart failure, lead management, pacemakers and defibrillators, supraventricular tachyarrhythmias, and ventricular tachycardia. His research focuses on electrophysiological predictors of susceptible atrial substrate for the onset and recurrence of atrial fibrillation, clinical outcomes of conduction system pacing compared to biventricular pacing in patients with mid-range ejection fraction, and outcomes after pulmonary vein isolation in patients with systolic and diastolic heart failure. Dr. Aziz has contributed to understanding vasovagal responses in ventricular tachycardia, the demarcation of ventricular tachycardia circuits, and the impact of guidelines on patient selection and outcomes after cardiac resynchronization therapy. His work also includes studying atrial asynchrony during persistent atrial fibrillation and the efficacy of empiric ablation strategies for polymorphic ventricular tachycardia and fibrillation.
Research topics
- Medicine
- Internal medicine
- Cardiology
Selected publications
Heart Rhythm · 2026-04-01
articleHeart Rhythm · 2026-04-01
articleHeart Rhythm · 2026-04-01
articleHeart Rhythm · 2026-04-01
articleHeart Rhythm · 2026-04-01
articleHeart Rhythm · 2025-04-01
articleOpen accessWomen Trainees in Electrophysiology and the Effect of Role Models
Circulation Arrhythmia and Electrophysiology · 2024-05-28 · 2 citations
letterOpen accessA Revised Definition of Left Bundle Branch Block Using Time to Notch in Lead I
JAMA Cardiology · 2024 · 10 citations
- Medicine
- Cardiology
- Internal medicine
Importance: Current left bundle branch block (LBBB) criteria are based on animal experiments or mathematical models of cardiac tissue conduction and may misclassify patients. Improved criteria would impact referral decisions and device type for cardiac resynchronization therapy. Objective: To develop a simple new criterion for LBBB based on electrophysiological studies of human patients, and then to validate this criterion in an independent population. Design, Setting, and Participants: In this diagnostic study, the derivation cohort was from a single-center, prospective study of patients undergoing electrophysiological study from March 2016 through November 2019. The validation cohort was assembled by retrospectively reviewing medical records for patients from the same center who underwent transcatheter aortic valve replacement (TAVR) from October 2015 through May 2022. Exposures: Patients were classified as having LBBB or intraventricular conduction delay (IVCD) as assessed by intracardiac recording. Main Outcomes and Measures: Sensitivity and specificity of the electrocardiography (ECG) criteria assessed in patients with LBBB or IVCD. Results: A total of 75 patients (median [IQR] age, 63 [53-70.5] years; 21 [28.0%] female) with baseline LBBB on 12-lead ECG underwent intracardiac recording of the left ventricular septum: 48 demonstrated complete conduction block (CCB) and 27 demonstrated intact Purkinje activation (IPA). Analysis of surface ECGs revealed that late notches in the QRS complexes of lateral leads were associated with CCB (40 of 48 patients [83.3%] with CCB vs 13 of 27 patients [48.1%] with IPA had a notch or slur in lead I; P = .003). Receiver operating characteristic curves for all septal and lateral leads were constructed, and lead I displayed the best performance with a time to notch longer than 75 milliseconds. Used in conjunction with the criteria for LBBB from the American College of Cardiology/American Heart Association/Heart Rhythm Society, this criterion had a sensitivity of 71% (95% CI, 56%-83%) and specificity of 74% (95% CI, 54%-89%) in the derivation population, contrasting with a sensitivity of 96% (95% CI, 86%-99%) and specificity of 33% (95% CI, 17%-54%) for the Strauss criteria. In an independent validation cohort of 46 patients (median [IQR] age, 78.5 [70-84] years; 21 [45.7%] female) undergoing TAVR with interval development of new LBBB, the time-to-notch criterion demonstrated a sensitivity of 87% (95% CI, 74%-95%). In the subset of 10 patients with preprocedural IVCD, the criterion correctly distinguished IVCD from LBBB in all cases. Application of the Strauss criteria performed similarly in the validation cohort. Conclusions and Relevance: The findings suggest that time to notch longer than 75 milliseconds in lead I is a simple ECG criterion that, when used in conjunction with standard LBBB criteria, may improve specificity for identifying patients with LBBB from conduction block. This may help inform patient selection for cardiac resynchronization or conduction system pacing.
Circulation · 2024
- Medicine
- Cardiology
- Internal medicine
Background: While conduction system pacing (CSP) has shown promise in mitigating the risk of pacemaker-induced cardiomyopathy compared to traditional right ventricular pacing, some patients undergoing CSP may experience declines in left ventricular ejection fraction (LVEF). We aimed to identify ECG predictors of LVEF decline after left bundle branch area pacing (LBBAP) or deep septal pacing (DSP). Methods: Consecutive patients undergoing LBBAP or DSP at a single center who had baseline LVEF >35%, follow-up echocardiogram at least 90 days post-implant, >20% ventricular pacing, and no coronary intervention during follow-up were retrospectively studied. Post-implant ECGs were analyzed for LBBAP capture (delayed RV activation with RSR’ pattern in V 1 or QRS duration <120 msec) or DSP (all others), V6 R wave peak time (<75 msec if narrow QRS or RBBB, <85 msec if LBBB), lead I time to notch >75 msec, and RS/rS pattern in V6. Primary outcome was absolute LVEF decline ≥15%. Results: A total of 67 patients met inclusion criteria with mean age 73 years, 45% female, 63% African American, 34% CAD, 18% cardiomyopathy, and 60% median LVEF (IQR 52-68%) at baseline. LBBAP was achieved in 39 (58%) and DSP in 28 (42%). Median pacing at follow-up was 99% over median follow-up of 15.6 (IQR 8-23) months. No differences were noted with respect to demographics, clinical comorbidities, or LBBAP vs DSP among patients with and without LVEF decline ≥15% (Table). Among ECG predictors, notch time in Lead I >75 msec was significant on univariate logistic regression analysis (OR 4.431, 95% CI 1.11-17.72, p=0.035, Figure) and with multivariate adjustment for age, baseline LVEF, history of cardiomyopathy or CAD. Conclusion: Lead I notch time >75 msec on post-implant paced ECG was associated with LVEF decline at follow up, albeit with broad confidence intervals. These findings suggest utility in evaluating paced QRS patterns after CSP to identify patients at risk for pacemaker-induced cardiomyopathy.
Journal of Interventional Cardiac Electrophysiology · 2024-08-17 · 3 citations
article
Frequent coauthors
- 49 shared
Roderick Tung
- 40 shared
Andrew D. Beaser
University of Chicago
- 39 shared
Hemal M. Nayak
The University of Texas Health Science Center at San Antonio
- 36 shared
Gaurav A. Upadhyay
University of Chicago
- 18 shared
Cevher Özcan
University of Chicago
- 17 shared
Dalise Y. Shatz
Banner - University Medical Center Phoenix
- 11 shared
Takuro Nishimura
Tokyo Medical and Dental University Hospital
- 9 shared
Michael Broman
University of Chicago Medical Center
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